Hardware watchdog for BBB

[kb2...@gmail.com]

HI, I have been working for a wile on safe power supply for BBB with backup power provided by supercapacitors. In case of power failure there is  just enough  time to safely and nicely shut down BBB. For some reason BBB does not always wake up fully. I need hardware dogwatch. Did anybody design such a thing? I was able to find some design for ardunio: http://www.playwitharduino.com/?p=291.
Anybody has any experience with hardware dogwatch for BBB??
Thanks in advance
Robert

[John Syn]

From: <kb2...@gmail.com>
Reply-To: <beagl...@googlegroups.com>
Date: Saturday, March 22, 2014 at 10:08 AM
To: <beagl...@googlegroups.com>
Subject: [beagleboard] Hardware watchdog for BBB

Hi Robert,

Developing a power supply that ensures a reliable shutdown down in the event of a power failure isn’t a simple design. You really need to monitor the input power supply and the state of the kernel to determine when to remove and reapply power to the BBB. You have to consider the corner cases such as:

1. power failure could occur during the boot up sequence
2. power failure occurred, triggering a shutdown sequence and then power is restored during the shutdown sequence.

With Linux, you cannot arbitrarily remove power during the boot up sequence and you cannot simply reapply power during the power down sequence. In the first case, when would it be safe to simply remove power to the BBB and in the second case, when would it be safe to recycle the power to the BBB. Currently there is no external info to determine the state of the kernel so you would have to add a kernel driver which will control a GPIO to signal when the kernel is in a safe mode (all volatile info written to non-volatile memory) and also monitor a GPIO used to interrupt the kernel when a power failure occurs. 

So now, you need an external state machine which tracks the input power supply, state-of-kernel and charge state of super caps. Timers are also required to ensure a proper power recycle. 

I hope I have covered everything you need to consider in your design, but perhaps others has some insights I haven’t considered. 

Regards,

John

  --
For more options, visit http://beagleboard.org/discuss
---
You received this message because you are subscribed to the Google Groups "BeagleBoard" group.
To unsubscribe from this group and stop receiving emails from it, send an email to beagleboard...@googlegroups.com.
For more options, visit https://groups.google.com/d/optout.

[William Hermans]

I am still not sure why anyone would need / want all this complexity.

Living offgrid, powered by solar panels which charge a battery bank, which then powers our home via an Inverter . . .  I am not sure why the same concept can not be used on the BBB.

1) Power the BBB via a small rechargeable ~5V power source.

2) charge this ~5V power source via AC mains, solar power, whatever.

3) Monitor power on the charge input, and when absent send a message to the kernel to shutdown / hybernate.

Then, all you need is to make sure your power source can work a few minutes with no input power applied. Perhaps even double this value for "safety".

The way I see things, there is nothing to complex about all this at all.

[John Syn]

From: William Hermans <yyr...@gmail.com>
Reply-To: <beagl...@googlegroups.com>
Date: Tuesday, March 25, 2014 at 12:04 AM
To: <beagl...@googlegroups.com>
Subject: Re: [beagleboard] Hardware watchdog for BBB

I am still not sure why anyone would need / want all this complexity.

Living offgrid, powered by solar panels which charge a battery bank, which then powers our home via an Inverter . . .  I am not sure why the same concept can not be used on the BBB.

1) Power the BBB via a small rechargeable ~5V power source.

2) charge this ~5V power source via AC mains, solar power, whatever.

3) Monitor power on the charge input, and when absent send a message to the kernel to shutdown / hybernate.

Then, all you need is to make sure your power source can work a few minutes with no input power applied. Perhaps even double this value for "safety".

The way I see things, there is nothing to complex about all this at all.

Not a problem when you are there to push the on button or reset your BBB when it locks up. What happens when there is no human intervention and the BBB is in some remote location? What happens during brown outs, power surges, power fluctuations, auto reclosure operations, power bypass, etc? What happens when you have 10K, 100K or even 1 Million devices running. Even a 0.1% failure rate will be a disaster. 

Cost is a primary factor so you cannot spend 10x on the power supply (batteries, solar panels; really?). Batteries are expensive and have a limited number of charge cycles, typically less than 1,000 cycles (less than 3 years). Actually, the circuit is even more complex because supercaps have a max voltage of 2.5 or 2.7 volts, so you have to stack them. Now you need an energy balance circuit to make sure all caps in series maintain an equal charge. During power fail, the voltage across these supercaps decrease, but you need to maintain a constant voltage, so you need a boost switching supply. The switcher cannot start until the supercaps have a minimum charge. I could go on, but yes the complexity is necessary to ensure a reliable supply. 

Your solution may be perfect for your requirements, but I think we are talking about a different operating environment. 

Regards,

John  

[Timbo]

What happens when you have 10K, 100K or even 1 Million devices running.

Now we know where all the BBBs went!

For home use I've rigged two BBBs together so that each can monitor and reset the other.  Every 5 minutes each board tries to send itself a message via an ssh connection to the other board.  If it fails to receive that message, it assumes the other board has crashed somehow and sends a reset.  If it still fails to get a response it carries out a power cycle.

In conjunction with a simple UPS such as the OP describes, this would probably be enough for normal use.

[John Syn]

From: Timbo <tim...@gmail.com>
Reply-To: <beagl...@googlegroups.com>
Date: Tuesday, March 25, 2014 at 6:12 AM

To: <beagl...@googlegroups.com>
Subject: Re: [beagleboard] Hardware watchdog for BBB

What happens when you have 10K, 100K or even 1 Million devices running.

Now we know where all the BBBs went!

Very funny. BBB wouldn’t work for my application but I do draw from Gerald’s brilliance ;-)

For home use I've rigged two BBBs together so that each can monitor and reset the other.  Every 5 minutes each board tries to send itself a message via an ssh connection to the other board.  If it fails to receive that message, it assumes the other board has crashed somehow and sends a reset.  If it still fails to get a response it carries out a power cycle.

In conjunction with a simple UPS such as the OP describes, this would probably be enough for normal use.

[William Hermans]

Yeah after I thought about it, after making my post I realized I did not include a way to bring the BBB back up.

For bringing the BBB back up after input power is back up I suppose I would use an MSP430 to monitor the input power, and a "keep alive" signal from the BBB to the MSP430. A Value line MSP430 such as the MSP430G2553 is low cost ( ~$2.5 in quantities of 1 ) can run off a single button cell for years. the MSP430G2553 also has SPI, I2C, GPIO's, and UART, as well as a few other niceties( hardware WDT, and Timer(s).)

So perhaps more complex than I originally led on, but perfectly doable, and not really all that complex. Just off the top of my head, I would use either a regular timer, or perhaps even use the hardware watchdog timer to cycle a reset on the BBB through a GPIO. With the keep alive signal being sent out over either SPI or UART.

Is this on track with what you had in mind, or are you thinking of something else, or is this too complex for your application ?

[John Syn]

From: William Hermans <yyr...@gmail.com>
Reply-To: <beagl...@googlegroups.com>
Date: Tuesday, March 25, 2014 at 3:41 PM

To: <beagl...@googlegroups.com>
Subject: Re: [beagleboard] Hardware watchdog for BBB

Yeah after I thought about it, after making my post I realized I did not include a way to bring the BBB back up.

For bringing the BBB back up after input power is back up I suppose I would use an MSP430 to monitor the input power, and a "keep alive" signal from the BBB to the MSP430. A Value line MSP430 such as the MSP430G2553 is low cost ( ~$2.5 in quantities of 1 ) can run off a single button cell for years. the MSP430G2553 also has SPI, I2C, GPIO's, and UART, as well as a few other niceties( hardware WDT, and Timer(s).)

So perhaps more complex than I originally led on, but perfectly doable, and not really all that complex. Just off the top of my head, I would use either a regular timer, or perhaps even use the hardware watchdog timer to cycle a reset on the BBB through a GPIO. With the keep alive signal being sent out over either SPI or UART.

Is this on track with what you had in mind, or are you thinking of something else, or is this too complex for your application ?

Hi William,

I like your solution. I used a GreenPak from http://www.silego.com/ which are really low cost $0.35 in small quantities. They are tiny (about 2mm square) and very robust; no need for WDT. Also, they work down to 1.8V, which is required when working with supercaps. 

Regards,

John

[William Hermans]

Hi John,

Yeah, the MSP430G2553 can go down to at least 1.8v, and I am thinking a good bit lower. I am thinking perhaps 1.2V at minimal clock / periph's( I'd have to read the datasheet again ) Now just because I am relatively new to embedded devices, and I know the MSP430's fairly well, I would choose these for myself. The MSP430 value line products can not beat or even meet that price by a long shot in small quantities. I think the lowest my buddy got a tube of 10 for ~$1.35 each a bit over a year ago. One or two off, personally I think this price is fair enough.

I haven't heard of the devices you're linking to, and the link doesn't work for me. So i can not even look to see exactly what it is. I would assume the MSP430G2553 would be overkill by comparison, feature wise.

So, I am not much of an EE, but my buddy is. Perhaps I could get him to design something up while I'll tie things together in software. This is something I personally have interest in as well.

[John Syn]

From: William Hermans <yyr...@gmail.com>
Reply-To: <beagl...@googlegroups.com>

Date: Tuesday, March 25, 2014 at 10:02 PM

To: <beagl...@googlegroups.com>
Subject: Re: [beagleboard] Hardware watchdog for BBB

Hi John,

Yeah, the MSP430G2553 can go down to at least 1.8v, and I am thinking a good bit lower. I am thinking perhaps 1.2V at minimal clock / periph's( I'd have to read the datasheet again ) Now just because I am relatively new to embedded devices, and I know the MSP430's fairly well, I would choose these for myself. The MSP430 value line products can not beat or even meet that price by a long shot in small quantities. I think the lowest my buddy got a tube of 10 for ~$1.35 each a bit over a year ago. One or two off, personally I think this price is fair enough.

I haven't heard of the devices you're linking to, and the link doesn't work for me. So i can not even look to see exactly what it is. I would assume the MSP430G2553 would be overkill by comparison, feature wise.

So, I am not much of an EE, but my buddy is. Perhaps I could get him to design something up while I'll tie things together in software. This is something I personally have interest in as well.

Hi William,

Strange, I just clicked on the link below and it works for me. Search Google for silego and greenpak. It’s really like a miniature mixed signal FPGA. They have a really nice software tool/simulator and dev board. I use these all the time instead of using discrete logic. They are really good for small state machines with inputs from timers, counters, analog comparators, lookup tables, macrocells, etc. 

[Super Twang]

I've just come across this conversation in my own search for a rock-solid, embeddable configuration for the BeagleBone Black.  I’m trying to develop an embedded controller device that needs to live behind walls, in ceilings and in other inaccessible places. ( It is for the automation of art & other electronic installations.)

From what I gather here, the BBB is not quite up to the task, without an external watchdog circuit (please correct me if I’m misreading this thread).

@John3909: Your suggestion of the GreenPak prompted my own discovery of that tech — it looks great, esp the ecosystem of tools around the platform. 

In looking around, I found some Silego application notes that implement a hardware watchdog for MCUs.  http://www.silego.com/products/352/312/AN-1058.html  This might be a useful starting point for anyone using GreenPak for a hardware watchdog.

@John3909: Does this design look like it might be a good fit for the BBB? (Not knowing how to read GreenPak internals, it is not obvious to me)

Alternately, I'm wondering in the two years that have passed since this thread started, if anyone has developed a hardware watchdog design for the BBB they'd be willing to share.  An open-source hardware watchdog for the BBB would go a long way towards ameliorating the hardware issues with the PMIC on RevC, and allow it to prosper as a base for applications where long-term reliability matters.

Although I’m first and foremost a software engineer, I've got some electronics chops (albeit mostly digital), but (sadly) very limited hardware design equipment (oscilloscope, etc).  [That said, I have iron, and will solder!]  I’d be happy to develop & contribute the software components for such a system (I’d envision a library + device tree overlay) if someone(s) else would like to partner up to design the hardware side.

Best,

ST

[evilwulfie]

We use an external msp430 for our intelligent watchdog

--
For more options, visit http://beagleboard.org/discuss
---
You received this message because you are subscribed to the Google Groups "BeagleBoard" group.
To unsubscribe from this group and stop receiving emails from it, send an email to beagleboard...@googlegroups.com.

To view this discussion on the web visit https://groups.google.com/d/msgid/beagleboard/c7fb39d8-84ef-4127-9db8-cd65a6965e31%40googlegroups.com.

[John Syne]

I haven’t worked on this in a while, but the circuitry I proposed was for a voltage monitoring and safe shutdown and startup. The AM3358 already has a watchdog timer and will reset the board if the watchdog is not serviced in a predefined period. My proposed circuit included supercaps to power the board during power failure so that the board can shutdown safely. You need a state machine to deal with all the corner cases, such as 

1) what happens if you have a power fail, you trigger a shutdown and then the power is back on before the shutdown completes. In that case, you have to power off the BBB, wait for the supercaps to charge and then reapply the power to the BBB. 

2) what happens if the power is on and the board begins to boot, but then the power fails before the board has completed it’s bootup. 

There are several more corner cases when you think through all the scenarios.

Also, you need a supercap charging circuit since supercaps are normally rated at 2.7V so you have to put them in series but one supercap may have lower impedance than the other so one supercap may exceed it’s max voltage and may in fact go negative during discharge. Your charge circuit must prevent both conditions. 

You will also need a boost regulator to keep the voltage on the processor constant as the supercaps discharge.

Lithium batteries would be easier, but then you are faced with the limited number of charge cycles and the limit life expectancy of these batteries. 

Just some ideas to think about. 

Regards,

John

--
For more options, visit http://beagleboard.org/discuss
---
You received this message because you are subscribed to the Google Groups "BeagleBoard" group.
To unsubscribe from this group and stop receiving emails from it, send an email to beagleboard...@googlegroups.com.

To view this discussion on the web visit https://groups.google.com/d/msgid/beagleboard/c7fb39d8-84ef-4127-9db8-cd65a6965e31%40googlegroups.com.

[John Syne]

On May 15, 2016, at 3:14 PM, evilwulfie <evilw...@gmail.com> wrote:

We use an external msp430 for our intelligent watchdog

So who or what monitors the MSP430? Since it is a micro-controller, it is easy to get it into a lock situation. All you need is a programable power supply which will ramp up and down the voltage into the micro-controller at predefined times and it will lock and become completely unresponsive. Granted this will rarely happen, but in our applications where 100K or more devices are installed, we cannot accept some devices locking up because of a power failure. 

Regards,

John

To view this discussion on the web visit https://groups.google.com/d/msgid/beagleboard/976bd440-2729-5157-8692-3357a8d607a0%40gmail.com.

[evilwulfie]

msp430 has an internal watchdog

To view this discussion on the web visit https://groups.google.com/d/msgid/beagleboard/E00049D5-E39B-42CB-8A5E-A19F4E51199F%40gmail.com.

[Super Twang]

Sorry guys.  I might be confusing my terms here, or misusing the phrase 'watchdog timer'.  Would 'hardware watchdog circuit' fit?  "Intelligent power switch?"  I'm not quite sure what to search for!

The circuit I'm looking for is what John3909 is describing; something to address the corner-cases around power and ensure graceful, and hands-off, system recovery amidst all of the corner cases (brownouts, drop+restart (incl at 'inconvenient' times, ie during shutdown, etc)).  

Fwiw, my application is already kicking the onboard watchdog, and relying on its reboot if the software system fails.  I need to make sure that that reboot ALWAYS happens, no matter what the power throws at it, as the system will be installed in walls, ceilings and such.

Does anyone know of a good public-domain/open-source external circuit design that might work around the BBB (or something close -- a good starting point)?  Or, even better, would anyone be able & willing to share their circuit design?  I realize that this kind of circuit requires some solid engineering to get right.  The EE part is a stretch for me, capability-wise, but I can offer software services in trade for hardware help. 

I'm personally blocked by this issue, and just trying to work out the best path forward, but I'd love to see this problem definitively solved for everyone using the BBB.  It is such a great platform. I'd love to ensure it'll always be online and ready for what we all throw at it.

Best,

ST

[Harvey White]

On Sun, 15 May 2016 17:08:40 -0700 (PDT), you wrote:

>
>Sorry guys. I might be confusing my terms here, or misusing the phrase
>'watchdog timer'. Would 'hardware watchdog circuit' fit? "Intelligent
>power switch?" I'm not quite sure what to search for!

I generally call a watchdog timer (and it can be external if desired)
as a timer that must be continually refreshed, if it times out, it
resets the microprocessor. However, the processor remembers that it
has been reset by a watchdog (most of them ought to), and then your
bootup routine will know that the program hung somewhere and didn't
reset the watchdog timer in time.

What the BBB needs is not so much a watchdog timer, but an intelligent
power monitor. If that processor (and it could be very simple) does
*not* have an operating system but simply runs embedded firmware, then
it will not suffer from shutdown problems as does the BBB.

It could have an operating system, but should not depend on file
systems being set up properly (a la windows or linux, I think).

You could use something as simple as an Arduino.

Harvey

[William Hermans]

What the BBB needs is not so much a watchdog timer, but an intelligent
power monitor.  If that processor (and it could be very simple) does
*not* have an operating system but simply runs embedded firmware, then
it will not suffer from shutdown problems as does the BBB.

It could have an operating system, but should not depend on file
systems being set up properly (a la windows or linux, I think).

You could use something as simple as an Arduino.

Harvey

I would probably never use an Arduino for this purpose. The cost is too high for starters.

An MSP430G2553 is perfect for this usage because it is an extremely low power MCU, that has hardware SPI, UART, I2C, WDT, ADC, PWM . . . and at least 14-16s pin available for use after the bare minimum are used for power, gnd, reset, etc. This MCU is also well supported in CCS, as well as through gcc, and the MCP430 MCUs are well known, and proven.

So, the G2553 has it's own WDT in case it ever get's stuck. It has it's own hardware ADC so it can monitor input power it's self. Then it has GPIO's which can be used to power down a BBB though toggling the power button, or reset the board by disconnecting power from input as needed. Plus it has it's own POR, and BOR features built in. As well as being an MCU with internal flash for storage it is for all intents and purposes immune to power loss.

Trust me though. My buddy and I have discussed this a lot over the coarse of the last 3 or so years, and even more lately as we've realized that reset on the BBB is essentially broken since it's only a soft reset. That requires the input power to be completely disconnected for a short amount of time.

Anyway, if I knew PIC, or NXP MCU's as well as the value line MSP430's, I might consider one of those too. But seriously, beating the power usage of a valueline MSP430 would be really hard. They can operate on a single button cell for over 10 years.

--
For more options, visit http://beagleboard.org/discuss
---
You received this message because you are subscribed to the Google Groups "BeagleBoard" group.
To unsubscribe from this group and stop receiving emails from it, send an email to beagleboard...@googlegroups.com.

To view this discussion on the web visit https://groups.google.com/d/msgid/beagleboard/pg6ijb17s4ie0fs5rv13vi67hdcd1fsf10%404ax.com.

[William Hermans]

ooops, I forgot the main concern. The MSP430 could also be use as an external smart watchdog. Just by poking a GPIO pin once in a while from a beagelbone. In code  this would be very easy, and not processor intensive at all.

• BBB twiddles GPIO pin
• Pin interrupt fires on MSP430, and toggles a bit flag.
• timer period ends, and sees bit toggled, or not.
• if toggled, repeat cycle.
• if not toggled disconnect / reconnect power to the Beaglebone, and then toggle the reset switch.

Another nicety of the G2553 MCU is that it has an on die temp sensor. Then since the MCU will spend 90% + of it's time in sleep mode, core temperature will not be above ambient temperature by very much, if at all. So you get a temperature sensor for free, if you care to hook up UART, SPI, or I2C back to the beaglebone.

I think that honestly, the MSP430G2553 is even too much hardware for the particular use case. But it's the only MCU I know of that uses so little power, costs so little, nd has all the required features for an external smart watchdog that can "physically" interact with an SBC, as well as monitor power on it's own.

[arsi]

Hi,

I use this:





PIC 10F200 source code:

/*
   File:   main.c
   Author: arsi

   Created on May 22, 2015, 10:32 AM
 */
#include <xc.h>
#include <stdbool.h>
#include <stdint.h>
#define _XTAL_FREQ 4000000
#pragma config WDTE = ON        // Watchdog Timer (WDT enabled)
#pragma config CP = OFF         // Code Protect (Code protection off)
#pragma config MCLRE = OFF      // Master Clear Enable (GP3/MCLR pin fuction is digital I/O, MCLR internally tied to VDD)

void delay1() {
    __delay_ms(1000);
}
bool flag = false;
int counter = 0;

void main(void) {
#asm
    CLRWDT
    CLRF TMR0
    CLRWDT
    MOVLW 0b00001111
            OPTION
#endasm
            CLRWDT();
    TRIS = 0b1110;
    CLRWDT();
    GP0 = 0;
    __delay_ms(500);
    CLRWDT();
    TRIS = 0b1111;
    CLRWDT();
    //pause for BBB boot up 
    for (int i = 0; i < 120; i++) {
        delay1();
        CLRWDT();
    }
    counter = 0;
    while (true) {
        delay1();
        if (counter < 120) {
            CLRWDT();
        }
        if (flag != GP1) {
            counter = 0;
            flag = GP1;
        } else {
            counter++;
        }

    }
}

*******************************************************************************************
wd script on BBB:

#!/bin/bash
sleep 10
echo 60 > /sys/class/gpio/export
echo "out" > /sys/class/gpio/gpio60/direction
while :
do
echo "0" > /sys/class/gpio/gpio60/value
sleep 1
echo "1" > /sys/class/gpio/gpio60/value
sleep 1

done

***********************************************************************************************

Arsi

---

--
For more options, visit http://beagleboard.org/discuss
---
You received this message because you are subscribed to the Google Groups "BeagleBoard" group.
To unsubscribe from this group and stop receiving emails from it, send an email to beagleboard...@googlegroups.com.

[Micka]

You dont need an external microcontroller....  Some watchdog from Texas do a good job like the uccx946. 

To view this discussion on the web visit https://groups.google.com/d/msgid/beagleboard/57397009.2000005%40chello.sk.

[Micka]

The UCCx946 is designed to provide accurate microprocessor supervision, including reset and watchdog functions. During power up, the device asserts a reset signal RES with VDD as low as 1 V. The reset signal remains asserted until the VDD voltage rises and remains above the reset threshold for the reset period. Both reset threshold and reset period are programmable by the user.

The UCCx946 is also resistant to glitches on the VDD line. Once RES has been deasserted, any drops below the threshold voltage need to be of certain time duration and voltage magnitude to generate a reset signal. These values are shown in Figure 1. An I/O line of the microprocessor may be tied to the watchdog input (WDI) for watchdog functions. If the I/O line is not toggled within a set watchdog period, programmable by the user, WDO is asserted. The watchdog function is disabled during reset condition

[arsi]

Hi,

The difference is  in the price UCC2946 3.35 EUR and PIC10F200T-I/OT 0.462 EUR

And microprocessor can be programmed just like I need..

---

From: Micka
Sent: Monday, May 16, 2016 9:50AM
To: Beagleboard, Gerald Coley
Subject: Re: [beagleboard] Hardware watchdog for BBB

[William Hermans]

Last time we bought MSP430G2553's we paid $1.35 USD each for 10. Right now, it lots of 1ku they sell for around $1 USD each. So I would imagine $2 USD each for lots less than 100 would not be unreasonable.

So, I do not know what the UCCx946 is capable of. But we looked into using an external watch dog, and it was not good enough.

#1 a watch dog can not tell if input power is 5V or not.

#2 You need to completely disconnect power, especially when having a battery hooked up. To get the beaglebone to "hard reset". A watch dog can not do this.

#3 perhaps a watch dog can toggle reset, but either way this is required.

--
For more options, visit http://beagleboard.org/discuss
---
You received this message because you are subscribed to the Google Groups "BeagleBoard" group.
To unsubscribe from this group and stop receiving emails from it, send an email to beagleboard...@googlegroups.com.

To view this discussion on the web visit https://groups.google.com/d/msgid/beagleboard/57397F2C.80609%40chello.sk.

[Mark Lazarewicz]

Exactly.  These cheap external chips have a rc time constant and are pulsed by a GPIO . Output can generate an Interrupt back to Bbb to save important data. 

Sent from Yahoo Mail on Android

To view this discussion on the web visit https://groups.google.com/d/msgid/beagleboard/CAF%2BMRtmfNSrCXk-egMpz-gGqzjt%3D8qRgsrzv2FbrQUqrLAw0Lw%40mail.gmail.com.

[evilwulfie]

not enough time for a clean shutdown

To view this discussion on the web visit https://groups.google.com/d/msgid/beagleboard/587089779.3315783.1463416888133.JavaMail.yahoo%40mail.yahoo.com.

[William Hermans]

The thing is: The PMIC already sends an interrupt when input voltage drops under 5V.  Same as when the power button is pressed. Aside from losing USB until you reboot, this is not the problem. Then problem is when you have power connected, and issue a shutdown now -h( or halt ). The board will be stuck until it is hard reset. This also occasionally happen when issuing shutdown now -r( reboot ). There is no pin out for the hard reset line on the processor. So we're forced to make due by completely disconnecting power.

In cases where power goes away all together, this again is not a problem. But when one uses a battery, the board will have power for hours. So a bullet proof solution needs a GPIO + power relay to completely disconnect power good for a few seconds. Otherwise you'll be stuck for up to several hours without a running system.

So again, the smart move is to use a low cost, low power MCU to handle all of this automatically. For remote applications. If the board is sitting on your desk, then the application is no big deal anyway, as well as giving you the ability to physically remove power yourself. At a remote site however . . .

Anyway, you all can debate all this until you're blue in the face. I know what the issues are because we've discussed, and have tested for all these situations. So do as you please.

To view this discussion on the web visit https://groups.google.com/d/msgid/beagleboard/8c341d52-63ca-04b3-a13a-1db3720e371a%40gmail.com.

[John Syne]

On May 15, 2016, at 4:25 PM, evilwulfie <evilw...@gmail.com> wrote:

msp430 has an internal watchdog

And so does the AM3358, so I’m not sure whats your point? If it is a micro-controller, it is not guaranteed to boot up successfully every time, given an unstable power supply. To start with, you need to make the power supply more predictable so that brown outs, dips and sags are not seen by the micro-controller and that power down only occurs if the input power fails for more than a specified time. Also, if you do start a shutdown, then a full power cycle is needed in a controlled manner. When input power returns, don’t boot until the input power looks reliable. 

This is where you need an understanding of how the power utility network operates, which includes understanding how protection operates, what an ARC (Automatic Reclosure Relays) do, etc. For example, when a large breaker trips due to a protective signal, the ARC will attempt to reclose that breaker, sometimes more than once. At night, in a storm, you will see your lights dim for a second or two; that is an ARC operation. When a transformer has water in the oil or when a insulator is arching, or a power line is arching on the ground, these all result in very strange power behavior. In summary, power failure isn’t just an on or off problem, but a multitude of more problematic cases. 

Regards,

John

To view this discussion on the web visit https://groups.google.com/d/msgid/beagleboard/300489a5-a027-8f30-a598-89be5b17b4a4%40gmail.com.

[evilwulfie]

spend 50 bux on a power supply to solve a 5 dollar problem  yeah right.

To view this discussion on the web visit https://groups.google.com/d/msgid/beagleboard/7BFABDDC-D4D0-4E6F-863C-1015E9794658%40gmail.com.

[Micka]

Gerald what is your opinion on this subject ? 

To view this discussion on the web visit https://groups.google.com/d/msgid/beagleboard/4b8c4f6e-abae-446c-d964-26d37b92d4b3%40gmail.com.

[John Syne]

I guess it is all about prospective. Perhaps for your application you are right. However, if you have 10K or 100K or more devices installed, and now you have to recall them all because they keep on going offline, then it isn’t a $5 problem.

Regards,

John

To view this discussion on the web visit https://groups.google.com/d/msgid/beagleboard/4b8c4f6e-abae-446c-d964-26d37b92d4b3%40gmail.com.

[Gerald Coley]

Add a a battery or super CAP. When the DC voltage goes away, the processor gets and interrupt. When SW get interrupt unmount the Flash and power down.

Invest in a real 5V power supply.

Gerlad

--

Gerald

 

ger...@beagleboard.org

http://beagleboard.org/

gco...@emprodesign.com

[evilwulfie]

yes correct. but as for powering the BBB back on you need a bit more there than a user pressing the power button
a nice external micro works great. Remember if you have a LIPO battery the BBB will not repower on after power is reapplied.

To view this discussion on the web visit https://groups.google.com/d/msgid/beagleboard/CAHK_S%2Bc4Y%3DCzkntAm-Upc7pQmp70_2d5FLb%3D70TtLxtE%3DxObqA%40mail.gmail.com.

[William Hermans]

Add a a battery or super CAP. When the DC voltage goes away, the processor gets and interrupt. When SW get interrupt unmount the Flash and power down.

When a battery is connected to the battery test points, this is exactly what happens now when you have the debian package acpid installed( sudo apt-get install acpid )

Invest in a real 5V power supply.

Would you mind elaborating further on what you mean by that Gerald ?

Gerlad

To view this discussion on the web visit https://groups.google.com/d/msgid/beagleboard/CAHK_S%2Bc4Y%3DCzkntAm-Upc7pQmp70_2d5FLb%3D70TtLxtE%3DxObqA%40mail.gmail.com.

[Gerald Coley]

There are a lot of cheap power supplies out there that do not like any drops on the mains, not very well filtered or robust. These can play havoc on the HW.

The BBB is a low cost board, with people trying to make it cheaper all the time. To make it cheap something had to go. What you are talking about here, is one of the things that went. An Atmel Tiny would be perfect as a power monitor. It can shut it down and wake it up once the power comes back. Even if it goes down for a moment, you can play it safe and shut it down and wait a while. Your call

All you have to do is add it to the board.

Gerald

To view this discussion on the web visit https://groups.google.com/d/msgid/beagleboard/CALHSORrT-JNkt-7M%2Ba%3DBND%3DFZjGS7Hspowj9bNigfE74zhMSPw%40mail.gmail.com.

For more options, visit https://groups.google.com/d/optout.

[lachlan]

This what you need is this, A small micro (stm8 is cheap and do just fine) ..   which talks to the BBB over the serial port, so you can send/receive commands/status..(pick your test)   load info.. etc..
this small micro is always power cyclical s once every 2 mints lets say..   you can never prevent the small micro from being power cycled.
It save's what is was doing..  and wake's up on the next power up..  check to see what test it was running..  lets say CPU load  on the BBB, if outside of allowed..  time.. load..  etc...
your reset's the BBB, or power cycle,  you can also check for correct power up of the BBB, and switch it too a diff-ant boot source etc..
so..  if the small micro git hit my a cosmic ray.. for example if will always power cycle.. of and on.. clear the error.. and recover.
you can also setup long path check's.. so a token is send to the BBB which has to come back in some time frame etc..    if out side the test range... your BBB task is frozen and needs a reset.. etc..
Pick you test... 

Lachlan.

[William Hermans]

There are a lot of cheap power supplies out there that do not like any drops on the mains, not very well filtered or robust. These can play havoc on the HW.

The BBB is a low cost board, with people trying to make it cheaper all the time. To make it cheap something had to go. What you are talking about here, is one of the things that went. An Atmel Tiny would be perfect as a power monitor. It can shut it down and wake it up once the power comes back. Even if it goes down for a moment, you can play it safe and shut it down and wait a while. Your call

All you have to do is add it to the board.

Gerald

Yeap, exactly our thoughts here. The Micro used is really inconsequential. So long as it does everything *you* want it to do.  I do not know Atmel parts well at all, but I do know several MSP430's. ST Micro MCU's would probably work too, as well as NXP's LPC800.

I picked the MSP430G2553, again, because I know the MCU better than most others. It also has hardware on chip ADC which I wanted to monitor input power. No other micro that I've looked at in the same price range had everything I wanted.

@other nay sayers.

Also as I stated before the MSP430G2* series has very robust PoR / BoR internal circuitry. It may lose power, but you're never( very unlikely ) going to stop it coming back up again exactly as planned. Unless power is removed gain . . .  this is not some embedded linux system that can have its disk corrupted. This is a very robust, bare metal MCU that is meant to be used in conditions like these.

--
For more options, visit http://beagleboard.org/discuss
---
You received this message because you are subscribed to the Google Groups "BeagleBoard" group.
To unsubscribe from this group and stop receiving emails from it, send an email to beagleboard...@googlegroups.com.

To view this discussion on the web visit https://groups.google.com/d/msgid/beagleboard/27b49949-a0f8-447c-a52e-9459da0d0bfe%40googlegroups.com.

[William Hermans]

Additionally. In our case we have ~1000ma 3.7v LiPO batteries hook up to a couple of our BBB's here. The board shuts down almost immediately( cleanly ). So the BBB will only probably run off this battery for a couple hours, but the MSP430G2* could run off that battery for years. Assuming te battery did not self discharge long before that. Which is probably exactly what it'd do.

[Super Twang]

Hey y'all (yes, I'm in Texas),

I have really appreciated all of the good ideas and thoughtful design ideas here.  There are some apples and oranges being discussed at times because the problem of BBB reliability is not single-fold.  In the hopes of providing a clearer "Big picture" of the issue, as well as to summarize some of my own research on the topic, I've attempted to capture the main points in this thread into an outline format.  If it is convenient, you can refer to specific problems/solutions/caveats by the outline number, ie ( III.A.1 ) in any subsequent discussions -- this kind of shorthand might clarify the issues that are being discussed, rather than having to spell this stuff out (or omit it) when talking about a point.

Is there a good spot on a WIKI for this somewhere?

Enjoy, and thank you!

ST

-------------------- DOCUMENT IS BELOW HERE

SUMMARY BBB RELIABILITY PROBLEMS & FIXES:

I. Problems:

A. System/Client Software Problems:

  1. Problem: Incomplete system/client sw startups ( why? -- can damage result with this? )

  2. Problem: Incomplete system/client sw shutdown

     a. Can cause system corruption

  3. Client or system software freeze-up (it can happen!)

     a. Can freeze device operation even in absence of power issues

B. Hardware Problems:

  1. Problem: BBB doesn't always restart without a hard-disconnect of power (known hardware issue)

     a. Always - when shutdown/halted (ie shutdown/halt)

     b. Sometimes - when hard cycled (ie power removed, reset button pushed)

C. Power problems

  2. Problem: Mains power can't be relied upon

     a. Power loss (ie blackouts)

     b. Partial power loss (ie brownouts)

II. Requirements:

  A. A "Reliability System" to address above problems.  

III. Needs:

  A. Backup power source for

     1. BBB until complete shutdown

     2. Additional components of reliability system

  B. Hard-Reset Circuit: to completely remove, and re-add power to the board (for I.B.1 above)

  C. Sensing: Need to detect

     1. Power off: both presence and duration (ie detect/differentiate I.C.2.a and I.C.2.b)

     2. System soft-freeze up (detect I.A.3)

     3. Power on: both present, and "Good" (ie good enough for full reboot + protected powerdown)

  D. State Machine to enforce guaranteed order, no matter what

     1. "Protected Shutdown": Complete shutdown after it has been initiated

        a. even if power up is specified during shutdown (in which case protected startup begins thereafter)

     2. "Protected startup": Complete startup once it has been initiated

        a. even if power is removed during startup (in which case protected shutdown follows)

 

     3. "Power Good" before Startup: Power remains detached until enough backup power for Protected Startup + Protected Shutdown

     4. "Complete" Power off after shutdown: Complete detachment of power from BBB to solve (I.B.1)

     5. Others?

IV. Solution Design Components/Approaches

   A. Backup power

      1. Li-po Battery backup

         a. Pros:

            i.   Long lasting

            ii.  Relatively simple circuitry to support

            iii. Greatest capacity

         b. Cons:

            i.  "Dangerous", thus travel/shipping restrictions

            ii. Limited recharge cycles

      2. Super capacitor-based Backup Power

         a. Pros:

            i.  No practical recharge cycle-limit

            ii. "Safe" enough for restrition-free transport/shipping

         b. Cons:

   i.   Increased circuit complexity, esp for 2-cell systems needed to produce 5v

      3. Coin-cell (to power Reliability System only)

         a. Pros:

            i.   Cheap

            ii.  Long-lasting (10+ years)

            iii. "Safe"

         b. Cons:

            i.   Only powers reliability system, need additional solution for BBB

    B. Hard Reset Circuit (Pretty well known problem with solutions out there)

       1. Relay (physical, or solid state)

       2. Some kind of transistor switch

    C. Sensing

       1. Mains Power off

          a. Voltage comparator of some sort

       2. System "Soft-freeze"

          a. BBB On-board software-controlled watchdog timer initiates reboot

       3. System initiated shutdown

          a. GPIO pin connected to Reliability System, change state on start

       4. System completed shutdown 

          a. heuristic delay after final GPIO pin state change on end (from IV.C.3.a just above)

       5. System initiated startup

          a. Implied action on "Power Good" (add'l sensing not needed)

       6. System completed startup

          a. GPIO pin connected to Reliability System changes state on "Startup complete"

       7. Mains Power On

          a. Voltage comparator of some sort   

       8. Mains Power "Good" (enough backup power available for Protected Startup + Protected Shutdown

    D. State Machine

       1. An MCU of some sort

          a. MSP430 series (William Herman/Wulfmans's recs)

             i. Pros: 

                * very low power + coin cell battery == >10 years backup life

                * onboard ADC for voltage measurement/sensing

                * inexpensive

          b. ST Micro series (ie STM8)

          c. NXP's LPC800 series

       2. Discrete logic state machine

          a. Pros

             i. More tolerant of brownouts(?) than unprotected MCU

          b. Cons

             i. Lots of soldering!    

       3. Hybrid Technology - Programmable Mixed Mode Circuits

          a. Silego GreenPak (John3909's rec)

             i. Pros

                * Nice dev kit ( < $60 )

                * Very inexpensive ( < $0.40 )

                * More tolerant of brownouts(?) than unprotected MCU (John can you comment on this?)

V. Commercially Available Solutions

   A. Andice Labs Power Cape (Available for BBB/RaspberryPi)

      http://andicelabs.com/beaglebone-powercape/

      Li-Po Battery Backup, with software readable battery voltage and current

      ~ $65 (with headers) 

   B. Juice4Halt (Built for RaspberryPi, not BBB, but could be repurposed, one would assume)

      http://juice4halt.com

      Dual Super-capacitor Backup, with State Machine implemented

      ~ $85 (5V, all told shipped to US)

   C. Others?

      

[William Hermans]

You can sum it all up into this; The problem is completely solved by using a battery and having acpid installed. Except you need a way to completely disconnect power, from the BBB's input, for a single, or perhaps two corner cases that would otherwise require a hard reset.

All these fancy high cost solutions are honestly ridiculous, and if you can just use an OTS UPS . . .

--
For more options, visit http://beagleboard.org/discuss
---
You received this message because you are subscribed to the Google Groups "BeagleBoard" group.
To unsubscribe from this group and stop receiving emails from it, send an email to beagleboard...@googlegroups.com.

To view this discussion on the web visit https://groups.google.com/d/msgid/beagleboard/a3163a27-66e2-4efd-af37-aa92414fb01e%40googlegroups.com.

[John Syne]

Most supercaps have similar travel restrictions as they contain hazardous material and can only be transported via ground. 

Correct. GreenPAK will always startup correctly. Micro-controllers, even those with brownout detections and power on reset can be shown to fail when the power does not startup cleanly.  

Cons

Small SMD package require PCB to use, but the GreenPAK development system can be used for prototyping. 

V. Commercially Available Solutions

   A. Andice Labs Power Cape (Available for BBB/RaspberryPi)

      http://andicelabs.com/beaglebone-powercape/

      Li-Po Battery Backup, with software readable battery voltage and current

      ~ $65 (with headers) 

   B. Juice4Halt (Built for RaspberryPi, not BBB, but could be repurposed, one would assume)

      http://juice4halt.com

      Dual Super-capacitor Backup, with State Machine implemented

      ~ $85 (5V, all told shipped to US)

This looks like a good solution.

   C. Others?

      

--
For more options, visit http://beagleboard.org/discuss
---
You received this message because you are subscribed to the Google Groups "BeagleBoard" group.
To unsubscribe from this group and stop receiving emails from it, send an email to beagleboard...@googlegroups.com.

To view this discussion on the web visit https://groups.google.com/d/msgid/beagleboard/a3163a27-66e2-4efd-af37-aa92414fb01e%40googlegroups.com.

[John Syne]

Batteries have a limit number of charge cycles. Now you are going to say the battery remains charged, so you don’t have an issue with number of charge cycles, but if you keep the battery charged to greater than 90%, the battery won’t last more than 2 to 3 years. You can extend the life of LiPO by limiting the charge to 60% of capacity, which is the charge percentage when you purchase a new battery. 

Regards,

John

To view this discussion on the web visit https://groups.google.com/d/msgid/beagleboard/CALHSORojJZp%3DwPr3nFRAiN9pf2MU-c4Cq2Ya96_CZ2oBvSWyOA%40mail.gmail.com.

[Dave Loomis]

> You can sum it all up into this; The problem is completely solved by using a battery and having acpid installed. Except you need a way to completely disconnect power, from the BBB's input, for a single, or perhaps two corner cases that would otherwise require a hard reset.

I love the no-nonsense mentality, and quality design behind this approach for most use cases. But, for some high-reliability use cases like mine -- a device permanently installed in a remote, client wall — batteries aren’t a great fit.

For long-term accessibility: Battery maintenance, even after years of initial functionality, is extremely inconvenient or impossible.
For insurance reasons: The potential liability of installing LiPo, which is known to have potential fire issues, into a client’s wall.
For shipping reasons: The added hassle of international shipping of LiPo-based systems.

> All these fancy high cost solutions are honestly ridiculous, and if you can just use an OTS UPS . . .

Hardware cost is relative. The “high” cost (<$100) of a system design is nothing, if it will potentially save me things like panicked client calls, last-minute international plane tickets and high-pressure field repairs. Those just aren’t fun. Obviously every project out there isn’t heading to a NASA rover, but in some lines of work this kind of service is expected when a high-end, mission-critical system goes down. In the end, if I do my job right, the price is just passed on to the client who is willing to pay a premium for a high reliability, maintenance-free product.

I’d like to be able to deploy those systems based on the BBB, because I know it, find the platform highly versatile, and a good match for the variety of projects I take on. I think the PRUs especially make this a very unique little SoC.

Best,
ST

[Gerald Coley]

Sounds good to me!

Gerald

--
For more options, visit http://beagleboard.org/discuss
---
You received this message because you are subscribed to the Google Groups "BeagleBoard" group.
To unsubscribe from this group and stop receiving emails from it, send an email to beagleboard...@googlegroups.com.

To view this discussion on the web visit https://groups.google.com/d/msgid/beagleboard/8A4F134B-E937-4958-8A25-E8BEDB02E6FC%40lumieria.com.

For more options, visit https://groups.google.com/d/optout.

[Super Twang]

@Gerald

I’m a bit new on this forum; forgive me if you’re not the right person to ask… (please, anyone else, respond if you are) Its just that I’ve heard other people request and defer to your opinion on things, and, well, you have a pretty official looking email address! :)  

I understand the goal of keeping the BBB cost low (part of what attracted me to it over the RPi in the first place).  I agree, it is good to keep it competitive and within the reach of hobbyists.  I realize it may not be as much of an issue to the use-cases of others, but it’d seem that an inability to keep a BBB reliably running without physically pressing its reset button is a bit of an Achilles Heel for the platform (speaking here not generally of UPS-style Mains protection, but specifically of the issue that sometimes prevents its restart without physically pressing the button.  IE you can’t simply use a OTS UPS, without some additional logic. )  It’d seem that anyone who wants to leave their device running for an extended period of time would be impacted by this.

Do you know folks at TI who are as invested as you are in the success of the BBB platform?  In my own research, I’ve come to understand that TI makes many of the components that might form the basis of a rock solid “Reliability System” (as discussed in this thread).  (Things like supercap chargers, buck-boost chips, etc)  It’d seem that this problem would be a natural fit for someone at TI to solve in the form of a TI Reference Design, or Application Notes for their product line on their end.  Such an effort would be a win-win.  TI would be able to sell more TI components, support the BBB user community and open the device to new use cases, and their resulting markets.  The BBB community would be able to implement (or purchase) the TI/BBB reliability circuit, and focus on their primary designs, without having to solve the same basic reliability issue over and over.

Is there someone at TI, I could present this idea to?  Is this the kind of thing that’d even get considered and resourced?  Is TI nimble enough to care, and responsive to the BBB user community?

Thanks for your thoughts,

ST

You received this message because you are subscribed to a topic in the Google Groups "BeagleBoard" group.
To unsubscribe from this topic, visit https://groups.google.com/d/topic/beagleboard/RaFm9AT7-2c/unsubscribe.
To unsubscribe from this group and all its topics, send an email to beagleboard...@googlegroups.com.
To view this discussion on the web visit https://groups.google.com/d/msgid/beagleboard/CAHK_S%2Bf%3Dk5zSYuJ95pf03BFrVxC5%3Dqm0YUguSZ%2B2_y1mwiSDkQ%40mail.gmail.com.

[Graham]

It all depends on what you are worried about.  

I have several BBBs that I use as servers, and I want them to be robust.

So while working through power backup and an external hardware watchdog per all the previous discussions, we have a thunderstorm roll through the area.

No close strikes, but the Ethernet network interface went catatonic, would not send or receive, but didn't throw any errors.  

I could not SSH into the command line.

But the local serial port/command line worked fine.  The kernel seemed to be happily running, and not worried about anything in particular.

The system logs looked like someone had disconnected the Ethernet cable during the storm, but the network was still physically connected, with the RJ-45 socket lights blinking.

A power cycle reestablished everything.

So, probably some kind of transient flipped a few configuration register bits and stopped the Ethernet interface. 

No physical damage.

This kind of thing can not be unique, because I note that there are Ethernet controlled power strips with "Auto-Ping."

Stated feature is “Auto-Ping” feature to intelligently reboot a locked-up AP, router, VoIP phone, server, camera. or other device automatically.

Web Power Switch 7.            http://www.digital-loggers.com/lpc.html

So either I can go buy a $115 smart AC power switch, or use an Ethernet-PIC instead of the MSP430.

--- Graham

==

[William Hermans]

This kind of thing can not be unique, because I note that there are Ethernet controlled power strips with "Auto-Ping."

Stated feature is “Auto-Ping” feature to intelligently reboot a locked-up AP, router, VoIP phone, server, camera. or other device automatically.

This isn't unique to the Beaglebones. We get close strikes here all the time during the summer, and in fact decapped a realtech ethernet bridge chip in a PoE switch last year . . . But my personal equipment gets reset all the time from static discharges from close strike several times a year. Mostly it's just a GbE switch I have in my bedroom, but other devices get messes up from time to time as well. Once or twice our PoE WDS routers have too . . .

--
For more options, visit http://beagleboard.org/discuss
---
You received this message because you are subscribed to the Google Groups "BeagleBoard" group.
To unsubscribe from this group and stop receiving emails from it, send an email to beagleboard...@googlegroups.com.

To view this discussion on the web visit https://groups.google.com/d/msgid/beagleboard/47e04409-af30-4c62-9b3b-445a82036380%40googlegroups.com.

[Gerald Coley]

I am no longer with TI. You would need to ask Jason as to the level of commitment that TI has toward doing something like this.

If there is a decently robust need for a platform based on the BBB, but with some more robust and desired features, I would be open to making that happen. 

Gerald

To view this discussion on the web visit https://groups.google.com/d/msgid/beagleboard/CALHSORqTdBG2XVL52pvECedfZvLEjtwv5KE0GovH4E6LP9z2mw%40mail.gmail.com.

For more options, visit https://groups.google.com/d/optout.

[William Hermans]

@Dave loomis

Fine, if something does not work for you then by all means don't use it. But the high cost rediculous stuff I was speaking to all uses batteries . . .so you're SoL there too.

Also, if LiPO is not good for you, think about switching to a different battery chemistry. Get crazy, think out side the box.

[Super Twang]

@Graham

Wow!  I hadn’t yet thought of Ethernet as a point of failure.  Apart from the (“It doesn’t always soft-reset" issue — see outline I.B.1.b) I’d guess you could solve this with the onboard watchdog timer.  Run some kind of daemon that periodically “Checks for good ethernet” (a bit vague, I know), if found, it tickles the watchdog, if not, it provokes a reboot.  But yes, the problem remains that the reboot doesn’t always complete.

Of course if your ethernet got fried, that’d turn into a reboot cycle without some logic to notify you of the problem, and stop after a number of cycles.

--
For more options, visit http://beagleboard.org/discuss
---

You received this message because you are subscribed to a topic in the Google Groups "BeagleBoard" group.
To unsubscribe from this topic, visit https://groups.google.com/d/topic/beagleboard/RaFm9AT7-2c/unsubscribe.
To unsubscribe from this group and all its topics, send an email to beagleboard...@googlegroups.com.
To view this discussion on the web visit https://groups.google.com/d/msgid/beagleboard/47e04409-af30-4c62-9b3b-445a82036380%40googlegroups.com.

[William Hermans]

Ethernet has always been a point of failure as much as Telephone lines have been in the past. Except for Ethernet it is usually less drastic as many networks are not physically accessible to the elements. Like ours, where we have two external WDS routers that are point to point 1/2 miles distance in between, with a power transformer connected to a house on one end that loves to be struck by lightning . . .;)

You received this message because you are subscribed to the Google Groups "BeagleBoard" group.

To unsubscribe from this group and stop receiving emails from it, send an email to beagleboard...@googlegroups.com.
To view this discussion on the web visit https://groups.google.com/d/msgid/beagleboard/AA5B0956-374D-45E8-9336-22899699F9E7%40gmail.com.

[Graham]

Twang:

Well, that is what the "Auto-Ping" is all about.

If I don't get a ping from you in the last two minutes, then you get power-cycled/rebooted.

There are IoT PICs that are ~$5 that can speak Ethernet and could be programmed to reset, or press the power button if 5V was present, and they had not heard from the BBB lately.

More appropriate monitoring for a server, than watching some GPIO wiggle.

--- Graham

[zamek42]

Hi All,

We have a power supply like this. We use it for a Wandboard.

Technical parameters:

input voltage:9-32VDC
output voltage: 5VDC/2500mA
there is a 25F supercapacity which can hold the power up to 30s after
the power broken.
There is an input GPIO for watchdog and an output GPIO to power ok signal.
We can make it for Beagleboard.

Please write me, if you interest.

--

thx
Zoltan (Zamek) Zidarics
programmer
email:zam...@gmail.com
Self Playing Pipe Organ Systems
http://replayorgan.eu

[Lachlan Audas]

Here is a example circuit.

It has WD CPU, with RTC with supper cap..  Batt, or low leakage cap,

 1: It will control the target system,  BBB, resberry PI,  etc.

 2: Power on the target system at preset time.

 3: WD processor is always power cycled, and save's it's current state to RTC or FRAM or flash.

 4: Allows alternate boot device on your target system if it supported on target. Can download image over Serial  or SPI..
    etc (In case of flash/SD fail on target), ram test... Diagnostics's.. etc

 5: Can check target system for correct startup,  can check target system for freeze etc.

     This are many options on how you check you target system, you can run shell commands on the target system for example

      to ping host's,  send check value's etc. It's up to you how smart you wont to be. Any thing you can do any serial port.. on linux

     for example.

6: supper reliable.

7: Back up power is up to you,... how to design for target requirements

8: And cheap !!

Lachlan,

PS: sorry about image size, as I can't get eagle to do a nice PDF !!

design can be in KiCad.. easy to convert.

Lachlan

--
For more options, visit http://beagleboard.org/discuss
--- You received this message because you are subscribed to the Google Groups "BeagleBoard" group.
To unsubscribe from this group and stop receiving emails from it, send an email to beagleboard...@googlegroups.com.

To view this discussion on the web visit https://groups.google.com/d/msgid/beagleboard/29065523-1e21-5cf4-0c8e-8f26b330ba18%40gmail.com.

[Super Twang]

@Graham

I’ll have to experiment with this. Thanks for the suggestion!  It is definitely a higher level approach that could be easier to piece together with low-cost OTS components.  

Do you have a specific PIC in mind?  If not, I can dig around for a good one.  Last time I used a PIC it was all assembly language, with no USB ICSP and a PC-only dev environment.  Has that changed? (I’m developing from a Mac)

Initially my thought was that it wouldn’t work for me because my device is designed to work while disconnected from a larger network (It is connected to a router broadcasting a private access point).  But, there is nothing preventing me from connecting a switch to the router, and then the device and an auto-ping power control to the switch.  My own little auto-ping network… Hmmm!  

ST

--
For more options, visit http://beagleboard.org/discuss
---
You received this message because you are subscribed to a topic in the Google Groups "BeagleBoard" group.
To unsubscribe from this topic, visit https://groups.google.com/d/topic/beagleboard/RaFm9AT7-2c/unsubscribe.
To unsubscribe from this group and all its topics, send an email to beagleboard...@googlegroups.com.

To view this discussion on the web visit https://groups.google.com/d/msgid/beagleboard/20debbaf-a5a3-48e3-95a1-2984b714daf4%40googlegroups.com.

[Super Twang]

@Lachlan
Thank you for sharing your design. I’m definitely learning from it and I’m sure others will too.
ST

[Lachlan Audas]

No problems,,    you can have the design files.. in eagle or kicad,

it's just a example..   but if you think about it,  it uses a old trick

from aircraft,   thou in this case it's a complete power cycle.
They would save what the CPU was doing in NV memory of some sort(I assume core memory)..
reset the CPU and reload the data..check it, and continue..
so there may have 5  reset a second.. etc..
remember airplanes can have many light  strikes..  etc.. 
and if your life is dependent's on  those chips getting it correct,
you wont to use every trick in the book!

I was on  a flight  (747-400)  bad day it was Sept 11, it was from

Australia to USA,  the pilot come on the PA and said there was some

problems with some on board systems and resetting it did not fix the problem.

So had to pull the circuit breakers.. for the part of the plain, and wait..

and reactivate them fix the problem,  so reset's don't always fix the problem..
even on a 747-400 power cycale was the only thing which work.

Lachlan.

Lachlan

--
For more options, visit http://beagleboard.org/discuss
---
You received this message because you are subscribed to the Google Groups "BeagleBoard" group.
To unsubscribe from this group and stop receiving emails from it, send an email to beagleboard...@googlegroups.com.

To view this discussion on the web visit https://groups.google.com/d/msgid/beagleboard/86973270-CDD1-4AC3-9AB5-F0A13951BBAB%40gmail.com.

[Super Twang]

Hi y’all,

Below is a snippet of an offline email exchange between myself and Gerald of Beagleboard.org… I’m reposting it here because I think it further clarifies some of the subtleties of what is being discussed here, specifically how brown-outs are what throw the wrench into a simple solution with existing hardware.  It also illustrates some real-world constraints Gerald et al are facing around a potential solution at the board level.  I hope this helps the bring anyone new to the discussion up to speed, as it helped me.

Best,

ST

As I understand it, the crux of the problem -- what prevents the use of existing off-the-shelf protection gear (like a stock UPS unit) — is the necessity to physically close the reset switch to reliably reboot the board.  To be honest, I’m not even sure if this is even a real “Issue" (although it is listed as such in the wiki), or just the upshot from a design decision you consciously made (say, to reduce costs).  I think there is broad agreement that this is a problem.  You’ve already built in some nice power management hooks (interrupts, watchdog and such) that ought to allow the system to be shut down gracefully when mains power is lost, it just can’t restart itself.

Sort of. If you close the rest switch, you can trash the file system. What you need is an interrupt to allow the processor to close the file system. That exists today. Having the super cap or battery gives enough power for the processor to complete that task and power down. When the DC is restored it powers back up. The issue is if it is a brown out, that is where things get messed up because it is not a clean shutdown and power up. 

Is the elimination of this particular physical switching requirement by itself, a tough problem to solve?  

No

 

Would it take a lot of (cost-increasing) new hardware?  

Yes. At least $3.

 

Would it need anything new in the kernel?  

No.

 

Any software support?  Wouldn’t it “Just work” as hardware outside of the OS?

It can if it is done right. 

The more complete, robust “Reliability system," such as is being discussed in the forum, is a whole different thing -- less issue, more feature --effectively designed to replace the UPS with a custom backup power system tailored for/integrated with the BBB, that also happens to mitigate the core switching issue.  You’re right, there there are a lot of opinions, and a lot of different use cases here.

Super Cap works fine.  It is just the corner cases that need to be handled.

If my reasoning is good, it would imply the overall “Reliability system" is a good match for external solutions, whereas eliminating the physical switching requirement would be a good thing to add to the mainline board.  

Yes as long as these additions are free or would actually reduce the cost.

[Graham]

Twang:

You could look at the PIC32MX5xx/6xx/7xx series or PIC32MZ series. 

The low end starts below $5, quantity one. They will need an external Ethernet phi chip.

32 bit MIPS core, program in C, full Ethernet stack available.

If you want to experiment, get a PIC32MX starter card.

Ti may have something equivalent on an ARM core.  I just happen to be more familiar with the PICs.

--- Graham

==

[William Hermans]

Super twang,

I honestly think you're over thinking the situation. It's good to try and cover all possibilities, but you're asking questions of people that have not answered specific questions that were answered by others already. There are several smart people on this group. Of which I'd like to count myself among them, but in my own case I know I do not think of everything. Which is why my buddy and I have talked at length on this subject trying to work everything out.

. . .And you know what, we missed something that thanks to Graham I'm thinking of now. A stale Ethernet connection is every bit as bad as a hung system.

@Graham,

What I propose is that you do not need an Ethernet Micro connected to the BBB. Instead, you have the BBB ping the outside world once every set time frame, and it a ping comes back unreachable after say 5-10 minutes. You just stop "kicking the dog". Which does present a potential problem that Your internet connection may just be down. But a remote system that reboots once every 5-10 minutes because the internet connection is down is not something I'd personally see as a bad thing. After all you're unable to connect to the system anyway.

You received this message because you are subscribed to the Google Groups "BeagleBoard" group.

To unsubscribe from this group and stop receiving emails from it, send an email to beagleboard...@googlegroups.com.
To view this discussion on the web visit https://groups.google.com/d/msgid/beagleboard/73c0f3ff-43b7-433c-8a9a-783162c7fef8%40googlegroups.com.

[Super Twang]

@William

You right I could be overthinking!  I’m juggling a lot of factors, and looking for both a quick, low-hanging-fruit, short term solution (ala off-the-shelf Ether-auto-ping, minimal hardware patch, or commercial product), as well as over the longer term a rock-solid well engineered long term solution (likely supercap-based).  I’m hoping what I contribute here might be as useful to others as all of the conversations on this topic (yours included!) that preceded me have been to me.  

It is admittedly hard to know when I’ve done “Enough,” esp. since I lack my own direct domain knowledge.  Part of the problem is being able to discern which design proposals in this and other threads are actually relevant to my own use case, and constraints.  You’ve had some great suggestions, and I like the way you approached your own design, but parts of it don’t work for me (LiPo-batteries, reasons stated prior).  Also, present in most everyone’s proposal is something small/cheap MCU-based.  Esp for the near term quick fix, the time investment required by learning a new MCU (or something like GreenPak), and its dev kit, (even though I’m quite interested), makes me feel admittedly a little desperate for alternatives.

In other news, you’re right, Graham’s dead-Ethernet scenario was something I hadn’t even considered!  Fortunately for my own case, most of the time my systems will be isolated from the greater network, with a 6 inch Ethernet run to a dedicated private access point.  So I won’t have as much potential exposure to lighting strikes on the Ethernet lines, etc, but also can’t ping control/watchdog from anywhere external.  Your own deployment — the “Lightning magnet” :) -- sounds like its dealing with a pretty gnarly environment!

My research on this is winding down so this channel will probably quiet down.  Again, thanks for the help.  

Best,

ST

To view this discussion on the web visit https://groups.google.com/d/msgid/beagleboard/CALHSORqPvrtMLD-QTgpKRoUyb0-QHjTwVVdeFFKNLJ%3DS2TGOwA%40mail.gmail.com.

[Graham Haddock]

William:

That would work.  

The only "edge case" I might see as a problem would be if your ping target went off line.  Then the BBB would reboot itself every ten minutes even though nothing was wrong with the BBB.  I guess you could ping several different targets in rotation and only reboot if they all disappeared.

This gets us back to a real cheap local watchdog.

As an aside: Does anyone know what test a computer runs to determine if it is connected to the internet?

Most desktop/laptop computers have a different network icon as to whether the network/WiFi you connected to has internet connectivity.   Is the Windows computer pinging some Microsoft location that is "guaranteed" to be up?

--- Graham

==

On Tue, May 17, 2016 at 2:30 PM, William Hermans <yyr...@gmail.com> wrote:

@Graham,

What I propose is that you do not need an Ethernet Micro connected to the BBB. Instead, you have the BBB ping the outside world once every set time frame, and it a ping comes back unreachable after say 5-10 minutes. You just stop "kicking the dog". Which does present a potential problem that Your internet connection may just be down. But a remote system that reboots once every 5-10 minutes because the internet connection is down is not something I'd personally see as a bad thing. After all you're unable to connect to the system anyway. 

 ==

[William Hermans]

William:

That would work.  

The only "edge case" I might see as a problem would be if your ping target went off line.  Then the BBB would reboot itself every ten minutes even though nothing was wrong with the BBB.  I guess you could ping several different targets in rotation and only reboot if they all disappeared.

This gets us back to a real cheap local watchdog.

You only need to ping one ip address. Your internet gateway IP. e.g. your first hop outside of your local network.

As an aside: Does anyone know what test a computer runs to determine if it is connected to the internet?

Most desktop/laptop computers have a different network icon as to whether the network/WiFi you connected to has internet connectivity.   Is the Windows computer pinging some Microsoft location that is "guaranteed" to be up?

--- Graham

I'm not 100% sure, but the test Windows does is not always correct. Sometimes the icon shows not connected, when in fact as soon as you try to surf something on the web, it goes to the working icon . . .

My guess is that it does some simple DNS tests, and then after a while it gives up checking.

--

For more options, visit http://beagleboard.org/discuss
---
You received this message because you are subscribed to the Google Groups "BeagleBoard" group.
To unsubscribe from this group and stop receiving emails from it, send an email to beagleboard...@googlegroups.com.

To view this discussion on the web visit https://groups.google.com/d/msgid/beagleboard/CANN_KV6MEtkBkkjA-xc3KKzeNRh6LDpoB1xrBnN%2BZo6gJgLX6w%40mail.gmail.com.

[Brian Anderson]

You might be interested in the Beaglebone Power Cape from Andice Labs (http://andicelabs.com). Ron recently posted a blog entry on using the Power Cape to address some of the issues you are raising. The Power Cape has an onboard microprocessor, battery charger, etc.

ba

[Mike]

On 05/17/2016 05:55 PM, William Hermans wrote:

William:

That would work.  

The only "edge case" I might see as a problem would be if your ping target went off line.  Then the BBB would reboot itself every ten minutes even though nothing was wrong with the BBB.  I guess you could ping several different targets in rotation and only reboot if they all disappeared.

This gets us back to a real cheap local watchdog.

You only need to ping one ip address. Your internet gateway IP. e.g. your first hop outside of your local network.

The need to ping an Internet host just adds to the requirements.  Pinging your local router IP would meet the requirement of whether the BBB interface is up.  Adding Internet connectivity just added more complexity.

To view this discussion on the web visit https://groups.google.com/d/msgid/beagleboard/CALHSORrk-KSfKb%3D%2By9tCHPNQSkvfC-K7YPr8cQsvmuwDXR6DCg%40mail.gmail.com.

[William Hermans]

The need to ping an Internet host just adds to the requirements.  Pinging your local router IP would meet the requirement of whether the BBB interface is up.  Adding Internet connectivity just added more complexity.

Come now do I really have to comment on something like this ? The solution is pretty obvious . . .

If your application does not require an internet connection, then don't ping an outside address. Ping your internal gateway . . .

To view this discussion on the web visit https://groups.google.com/d/msgid/beagleboard/ff9dc15c-5863-3d8a-ad54-f3800b5db277%40gmail.com.

[Lachlan Audas]

I think we need to look at the big picture,

many system's  have the same problem.    Power monitor, with task monitor... with reset and  power of/on

power back up..   be that battery or supper caps or standard caps etc.

While we are all thinking of meeting our current needs. Taking the bigger picture will  allow much better long term fix

for the problems.   But that requires  some effort and time by good designers, and programmer, with good doc's

to allow the average guy to make good use of it.  with out too much work or hart burn.

but this needs a real commitment, from the developers,   not just few mint's writing some good ideas

in some support group,  be that BBB,  or Raspberry PI  or pick your platform.

It would also nice to have all this in Open hardware and software.  KiCad, and GCC or SDCC,

Perhaps putting it all into a VM image, so any one can run it,  as long as host system supports a VM player of some

sort.    But who is willing to put the time and effort  to make this happen ?

Lachlan.

To view this discussion on the web visit https://groups.google.com/d/msgid/beagleboard/CALHSORpXxmBek%3DY21CNBNQCaCp7UgbBh0WnyRXSqUqrnsU7MWw%40mail.gmail.com.

[Mark Lazarewicz]

Be careful about taking hardware design info from computer science degree types.  John seems to understand hardware this other dude bill is a blow hard and a

Sent from Yahoo Mail on Android

On Mon, May 16, 2016 at 3:34 PM, John Syne

<john...@gmail.com> wrote:

On May 15, 2016, at 4:25 PM, evilwulfie <evilw...@gmail.com> wrote:

[William Hermans]

Be careful about taking hardware design info from computer science degree types.  John seems to understand hardware this other dude bill is a blow hard and a

That comment, and a nickle is worth about 5 cents. . .

--
For more options, visit http://beagleboard.org/discuss
---
You received this message because you are subscribed to the Google Groups "BeagleBoard" group.
To unsubscribe from this group and stop receiving emails from it, send an email to beagleboard...@googlegroups.com.

To view this discussion on the web visit https://groups.google.com/d/msgid/beagleboard/746532426.5197607.1463625501671.JavaMail.yahoo%40mail.yahoo.com.

[Micka]

He didn't finish his sentence. 

To view this discussion on the web visit https://groups.google.com/d/msgid/beagleboard/CALHSORqM8ewgB4SmnS%3DeD19i2ALwH%3D32LMMx7_VvnNdGXXwyew%40mail.gmail.com.

[William Hermans]

He didn't finish his sentence.

Still a useless comment. as well is this one, in the context of the desired discussion.

To view this discussion on the web visit https://groups.google.com/d/msgid/beagleboard/CAF%2BMRt%3DpV4Y%3Dcg2-BrDPXoCpzUCbasDYYZ%3DTUN8T6%2BSm_vQWvQ%40mail.gmail.com.

[Lachlan Audas]

Have a look at https://en.wikipedia.org/wiki/Lithium_iron_phosphate_battery

Depending on current/temperature  they have much better life,  up to 10,000 cycles

and much better fire safety than LiPo,  you may even be able to ship then on flights.

Supper caps,  don't have a good life time,  in fact they much worse then

Aluminum Capacitors

example the LGU1H103MELB 100,000uF has a life 3000 Hrs @ 105°C  and much more life at 25C

and it rated for -40C to +105C,   and 4.09 amps ripple ratting, and cost $2  in 5k

where as the BZ015A104ZSB 100mF (100,000uF) supper cat  has only  1000 Hrs @ 70°C and cost $6.000 in 5k

(Digikey prices)

So to get the Max life,  use the step up switching reg to say 40V  (remember that energy on capt is = 1/2CV^2 )

so double the voltage is 4 times the energy)  then user a switch to step down to you required voltage/current

So for max and life,  only switch to the backup Caps when power fail's, that way they remain cool,

give max life,  and will give you  good hold times.  And of course all under mic-controller control.

per my example circuit.. (example dose not have the control circuit, but can be easily added )

Lachlan

On Mon, May 16, 2016 at 4:52 PM, Dave Loomis <da...@lumieria.com> wrote:

> You can sum it all up into this; The problem is completely solved by using a battery and having acpid installed. Except you need a way to completely disconnect power, from the BBB's input, for a single, or perhaps two corner cases that would otherwise require a hard reset.

I love the no-nonsense mentality, and quality design behind this approach for most use cases.  But, for some high-reliability use cases like mine -- a device permanently installed in a remote, client wall — batteries aren’t a great fit.

        For long-term accessibility:    Battery maintenance, even after years of initial functionality, is extremely inconvenient or impossible.
        For insurance reasons:          The potential liability of installing LiPo, which is known to have potential fire issues, into a client’s wall.
        For shipping reasons:           The added hassle of international shipping of LiPo-based systems.

> All these fancy high cost solutions are honestly ridiculous, and if you can just use an OTS UPS . . .

         Hardware cost is relative.  The “high” cost (<$100) of a system design is nothing, if it will potentially save me things like panicked client calls, last-minute international plane tickets and high-pressure field repairs.  Those just aren’t fun.  Obviously every project out there isn’t heading to a NASA rover, but in some lines of work this kind of service is expected when a high-end, mission-critical system goes down.  In the end, if I do my job right, the price is just passed on to the client who is willing to pay a premium for a high reliability, maintenance-free product.

I’d like to be able to deploy those systems based on the BBB, because I know it, find the platform highly versatile, and a good match for the variety of projects I take on.  I think the PRUs especially make this a very unique little SoC.

Best,
ST

--
For more options, visit http://beagleboard.org/discuss
---
You received this message because you are subscribed to the Google Groups "BeagleBoard" group.
To unsubscribe from this group and stop receiving emails from it, send an email to beagleboard...@googlegroups.com.

To view this discussion on the web visit https://groups.google.com/d/msgid/beagleboard/8A4F134B-E937-4958-8A25-E8BEDB02E6FC%40lumieria.com.

[Super Twang]

@Lachlan
Thanks for the info Lachlan.

Re: Supercap reliability…
My basic understanding is that if you design with supercaps for a “Everyday” (ie not too hardcore) indoor use case, and keep them within some pretty obtainable operating conditions they effectively last forever. Obviously there’s some ambiguity (“everyday” “pretty obtainable”, “effectively”) in the prior assertion, but...

My particular use case — indoor temps but in a wall, 5v power — might see a temp range of 15° - 35°C max I’d guess. The 70°C - 105°C you’re talking about would have to be a pretty harsh/industrial environment, no?

Does anyone (who has done it, or knows how) have a sense of how straightforward it is to achieve a supercap-based system design that keeps the components in a range that’d keep them healthy for “Effectively forever?” ie 20k+ cycles? (better than bats) 100k+? (effectively forever) Or, do the requirements we’re looking at for a basic, indoor, power system really push the supercaps into the “Quickly-used-up” zone?

Best,
ST

[Lachlan Audas]

It may not be out door's.. the electronics/computer's may be inside near a heat source,

I having seen electronics covered up by the end user's many times. (how many routers have you seen under
a pile of books..  clothing ? ..etc ) then there is fan's breaking,  air ventilation hole's fill with dust, cat hair etc.

it's not just out door's  which may provide and nasty environment.

The second problem is super cap's have high internal resistance, which limit's how much current you can pull

from them.  Problem there is problem is how much of the capacity of the super cap are you using ?

a 5V super cap backing up power to a 5v to 3.3v  switching reg,  or liner reg may only give you 4.3 volts before

the reg start's dropping the 3.3v power rail.   So there may be only 0.7V of the super capacity you are using.

And to get around that, you need a SEPIC switching reg, and of course your drawing big currents once you start drooping to 1 or 2 volts of the super cap.  So the cost of having a Electro  running at 40 or 50V,  where you will

get almost all of it's capacity is not a bad trade off, when you see that you will have even bigger problem with supper caps and extracting there full capacity.   And you will be switch much higher currents to get your 3.3V's from it.

Lachlan

Best,
ST

--
For more options, visit http://beagleboard.org/discuss
---
You received this message because you are subscribed to the Google Groups "BeagleBoard" group.
To unsubscribe from this group and stop receiving emails from it, send an email to beagleboard...@googlegroups.com.

To view this discussion on the web visit https://groups.google.com/d/msgid/beagleboard/F2A9E16C-3FED-44BD-AE07-F928C1477305%40gmail.com.

[William Hermans]

@Super Twang,

Sure super caps are usable, there are a few on these groups who do use them in place of a battery. Last time I personally looked though, cost was very prohibitive. For instance:

http://www.ebay.com/itm/like/262291173781?lpid=82&chn=ps&ul_noapp=true

$16.50 + $5.50 shipping each ? How many farads do we need to keep the board up for 30-60 seconds ? But let's assume two of these in series( because 2.7v is not enough ).

versus something like this:

http://www.ebay.com/itm/Lipo-Battery-Replacement-battery-for-808-18-Car-Key-Camera-Mini-DVR-60-minutes-/251600381055?hash=item3a948d247f:g:vu4AAOSwRLZT1MJd

Anyway, I did not look too long, but lower capacity super caps did not sem to drop in price much. 120 farad caps seemed to be pretty close in price too.

So, for a one off solution maybe not too much of a big deal, but for many, many systems. That cost is going to be far too high.

On Thu, May 19, 2016 at 8:33 AM, Super Twang <super...@gmail.com> wrote:

Best,
ST

--
For more options, visit http://beagleboard.org/discuss
---
You received this message because you are subscribed to the Google Groups "BeagleBoard" group.
To unsubscribe from this group and stop receiving emails from it, send an email to beagleboard...@googlegroups.com.

To view this discussion on the web visit https://groups.google.com/d/msgid/beagleboard/F2A9E16C-3FED-44BD-AE07-F928C1477305%40gmail.com.

[William Hermans]

Oh and for those worried about the LiPO chemistry . . . http://www.all-battery.com/15pcsnicdsubc2200mahrechargeablebatteryflattop-90626.aspx?utm_source=GoogleShopping&utm_medium=GDF&gdftrk=gdfV26767_a_7c354_a_7c922_a_7c90626&gclid=CJuytLPW5swCFYaTfgod0bgHeg

Problem is, you need three, maybe four of these. But cost would be ~$6-$8. Additionally 2200mah is a bit much if all you're going ot do is shutdown right away. So perhaps the AA cell equivelent, and those would cost less. SubC is the cell type typically used in cordless drill packs . . .

To view this discussion on the web visit https://groups.google.com/d/msgid/beagleboard/CAMkt-MvJMz8Ab_xjC6uXnGWw6maqfEWMYFbJAzO73p0msAxCnQ%40mail.gmail.com.

[Lachlan Audas]

NiCad's are bad news..  They are extremely toxic, and nasty.

I would not use them,   Have a look at https://en.wikipedia.org/wiki/Lithium_iron_phosphate_battery

much better option.

Lachlan

To view this discussion on the web visit https://groups.google.com/d/msgid/beagleboard/CALHSORqK7yJ6yEtajxN97w_%3DY3u-fMie4DT%2B3apOqrizpzBpKg%40mail.gmail.com.

[William Hermans]

My point is, there are many different battery chemistry types. Then at some point if you want to "play" you're going to have to "bargin with the devil" one way or another.

To view this discussion on the web visit https://groups.google.com/d/msgid/beagleboard/CAMkt-MtqPhbiybN6a%3D9gnN8fjdfGiT%3DjteZe2pN6wAc5DWPaiw%40mail.gmail.com.

[William Hermans]

Two of these http://www.all-battery.com/LiFePo414500Button-topCylindrical3.2V400mAhRechargeableBattery30225.aspx?utm_source=GoogleShopping&utm_medium=GDF&gdftrk=gdfV26767_a_7c354_a_7c922_a_7c30225&gclid=CPP-mNDa5swCFU1gfgodSBUB1w

Would be good enough for around one hour up time maybe. But honestly I know nothing of lithium iron phosphate batteries. I'd be "worried" how many recharge cycles they last before turning to junk.

[Lachlan Audas]

Read and you will be supersized how good they are!

Lachlan

To view this discussion on the web visit https://groups.google.com/d/msgid/beagleboard/CALHSORqoR75J33g7%2BNoCm6K_bE%3DxM8ByVrNuPoiT6tVkvG6LYA%40mail.gmail.com.

[zamek42]

Hi All,

Yes we have some experience about supercaps.

We have an organ controller which is working two years ago,
approximately 3-4 on/off per day. Yes it is an indoor application.
Our second application is an industrial environment with Pandaboard
which is working since last september approximately 1 on/off per day. It
is a semi indoor environment.
Our third application is a timelapse camera system with Raspberry (
http://1nap1perc.hu/pecsi-magashaz-bontas/ ) which is started at early
of march. It is an outdoor application which is working 7/24.

In other point of view, if you checked the parameters of supercap for
example
http://www.newark.com/illinois-capacitor/506dcn2r7q/super-capacitor-aluminum-elect/dp/90R9922
you can see:

operating temperature: -40-+60C
Life cycles: 500000

A simple NiCd accumulator is much more weight, and its lifecycle is much
more less, the operating temperature is 0-45C and lifecycle is less than
10000.

So supercap seems to be ideal for power supply to an embedded system,
but it needs a little bit complicated controller electronic.
best regards,


--
Zoltan (Zamek) Zidarics
programmer
email:zam...@gmail.com
Self Playing Pipe Organ Systems
http://replayorgan.eu

[William Hermans]

Certainly there wil be use cases for all. But one thing you need to be aware of with recharge cycles on batteries. Is that a recharge cycle is only counted when the battery voltage falls below a certain percentage. I believe this percentage is difference for every chemistry type. But I can say that for lead acid batteries, the recharge cycle is two fold.

First of the battery discharge goes below 75% this is a normal recharge cycle.

Second, if the battery goes below 60% discharge is is akin to taking away 100 normal discharge depth cycles.

But again, other chemistries I know are going to be different as some stay fairly steady in voltage throughout their whole discharge cycle.

--
For more options, visit http://beagleboard.org/discuss
--- You received this message because you are subscribed to the Google Groups "BeagleBoard" group.
To unsubscribe from this group and stop receiving emails from it, send an email to beagleboard...@googlegroups.com.

To view this discussion on the web visit https://groups.google.com/d/msgid/beagleboard/36c43943-2e37-e473-1524-398120205a19%40gmail.com.

[William Hermans]

Oh, right, heh, so the main point I had for the above was that if you never discharge a battery below 90%, then cycles are very likely not counted. Which is another problem in of its self. Batteries do need to be "exercised".

Another thing I was considering just now is that these Lithium iron phosphate batteries are indead pretty cool. However, they would require external circuitry to use with this board. Which is not necessarily a bad thing, but if you're looking to keep costs at a minimum. Then they are not the most ideal solution.

[John Syne]

https://en.wikipedia.org/wiki/Supercapacitor

If you operate the supercap at lower than max voltage and keep the temperature at close to 25C, the supercap will last as much as 20 years. No battery comes even close. You also need to look at lifecycle cost, not just cost of components. If you have to switch out the battery every few years, then the lifecycle cost for a battery will be much higher than supercaps. 

Regards,

John

To view this discussion on the web visit https://groups.google.com/d/msgid/beagleboard/CAMkt-MtdXLKP3VUTav_d_uGew4OAQfWT0iVSO9Zd6%2B5a0pYxUA%40mail.gmail.com.

[Lachlan Audas]

All design is a trade of, if you can control your environment that is the best of all possible words,
no lighting strike's, no one using there cell phone's 2 cm away from you board,  clean air,
no toxic chemical attacking your connector's to deal with.
And of course if you can afford the very best Mil speck parts, that's even better.
But most designers are not in that boat, and need to do the max with the lowest cost.
that where the hard work is.

Lachlan

 

To view this discussion on the web visit https://groups.google.com/d/msgid/beagleboard/405D3ADC-57FB-49C2-BFFF-FA6597936E08%40gmail.com.

[William Hermans]

All design is a trade of, if you can control your environment that is the best of all possible words,
no lighting strike's, no one using there cell phone's 2 cm away from you board,  clean air,
no toxic chemical attacking your connector's to deal with.
And of course if you can afford the very best Mil speck parts, that's even better.
But most designers are not in that boat, and need to do the max with the lowest cost.
that where the hard work is.

Lachlan

Exactly. Plus many people would view having to replace a part every couple years as a potential source of income - From service calls. I can say though that for our own application. Where out boards would be deployed. Power outages may not be impossible, but usually are dealt with immediately. Also, backup generators are typically in place too. So a single LiPO battery is just a low cost added bit of insurance.

To view this discussion on the web visit https://groups.google.com/d/msgid/beagleboard/CAMkt-Mu7bxrQ7jgbvmQ02TCagEawss2QmhWF%3D3gaVLOYmRzEeA%40mail.gmail.com.

[Super Twang]

I’m currently looking for low-hanging fruit solutions to improve the BBB’s reliability at the moment and came across this.

This open source project aims to provide a generic API to many off-the-shelf UPS systems, usually via a serial/usb/ether connection. I haven’t investigated this in depth yet, but it would appear that it gives you the software hooks to at least shut the bbb down when the mains go off, potentially monitoring battery levels down to a certain point first. There’s still be some external logic needed to do a full solution (as described in the rest of this thread), but it could be an interesting component of a system.

http://networkupstools.org

They seem to support loads of OTS devices.

The debian metapackage name is ‘nut’ (for network ups tools), fwiw.

ST

[Lachlan Audas]

Yes.. it's been around some time,  I have used it on my UPS for desktop computers.

worked well in that application.

--
For more options, visit http://beagleboard.org/discuss
---
You received this message because you are subscribed to the Google Groups "BeagleBoard" group.
To unsubscribe from this group and stop receiving emails from it, send an email to beagleboard...@googlegroups.com.

To view this discussion on the web visit https://groups.google.com/d/msgid/beagleboard/B7E33771-0A0A-4BB1-925A-B3DA06A21EEF%40gmail.com.

[AVR]

Dear Harvey

Is it really means that absence of operating system on BBB eliminates shutdown problems from unpredictable power loss?