Arduino Based LED Clock

[Zachary Austin]

Hi all,

I am looking at a new project for myself and I stumbled across someone online who has made an LED clock but used a "circle" principle rather than a digital display. It's not my original Idea but its something I would like to have a go at.

Here is an image of roughly where I would like to end up.

I am stuck thinking of a way to drive 180 LED's! I have been drawing up a schematic with a bunch of TLC5940 IC''s, but I have encountered a problem when wiring them up. I would like to clock to be able to connect to an NTP server via ethernet. I want to base the clock on the Freetronics EtherTen. My problem is that all the schematics I've looked at all use the same pins as the ethernet module on the etherten. I would like to know if I could just move the TLC5940's to different pins or whether I have to find a different IC, I considered the 74HC595's.

Any other input or ideas are welcome!

Thanks,

Zac

[Tim]

Just use addressable leds?

You could run then all from one pin with no additional hardware that way.

Tim.

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[Zachary Austin]

To be honest, I have never heard of addressable LED's.

After doing a bit of quick internet research I have figured out what they are and they look pretty cool.

Where would I be able to purchase them? I had a look at retailers but I could only find the LED strip version.

Thanks Tim    :-)

Zac

[Madox]

I think I still have a "bunch" but you are probably better off using the strips unless you want to make custom pcbs.

Actually I have a bunch on small pcbs too... Let me know roughly how many you need?

[Zachary Austin]

I might have a PCB made with Freetronics, I am planning on having three circles of LED's one for seconds, minutes and hours. Each circle with 60 LED's (180 total). I am looking at a PCB because I would rather pay for a PCB than having to sit down with a soldering iron and wire up 180 LED's. I know thats a lot of LED's. Would I be able to get enough power for that many LED's from an Arduino?

Thanks,

Zac

[Andrew Larkin]

You can use the led strip. Just need to mount it edgewise so you can create the ring. Use a laser cut acrylic diffuser to redirect the light forward. 

-------- Original message --------

From: Zachary Austin <zac.au...@gmail.com>

Date:08/10/2015 7:38 PM (GMT+10:00)

To: Robots & Dinosaurs <sydney-h...@googlegroups.com>

Cc:

Subject: Re: [RnD] Arduino Based LED Clock

To be honest, I have never heard of addressable LED's.

After doing a bit of quick internet research I have figured out what they are and they look pretty cool.

Where would I be able to purchase them? I had a look at retailers but I could only find the LED strip version.

Thanks Tim    :-)

Zac

[kris]

no, you can't power that many led's through the arduino.

there is a roll of apa102c addressable led's at the space (they are probably spaced too wide for your application but feel free to wire them up and have a play.

adafruit calls them "dotstars" but they are actually apa102c and very simple to use, and doesn't require tight timings like the others.

https://learn.adafruit.com/adafruit-dotstar-leds

here is the page that tells you the power requirement:
https://learn.adafruit.com/adafruit-neopixel-uberguide/power
the power draw for both neopixels and dotstars (ws80.. and apa102c) are the same. they are RGB so can do many colours. essentially they are 3 (red, green and blue LED in one package) each colour takes 20mA at full brightness, then times 3 colours = 60mA.
But you won't want to run these at full brightness (unless you are trying to tell the time from the moon). so 20mA is good.
20mA * 180 leds = 3600mA or 3.6 Amps

so your going to need a fairly meaty power supply.
something like this

http://www.ebay.com.au/itm/Plugpack-5V-DC-4A-Switchmode-Power-Supply-with-Fixed-2-1mm-Tip-and-N-Tick-/111408939144?hash=item19f07d8088

however, if you are building your own board, you can do something interesting called mulitplexing with normal LED's (you might be able to do this with addressable; you'd need to ask someone more experienced than me).
multiplexing is where you turn each 'ring' of led's on one at a time, but you do this really fast so your eyes can't see it. the result is you will drop the power requirement by two thirds, but you'll also be much lower bightness.
...leds in general are very bright...so you should be fine

kris

--

[Tim]

Zach the WS2812 addressable LEDs have a 3.5-5v input, and a data line that connects to the Arduino. You can control all the lights in the strip from that one pin. Any color, any brightness. The strip is great to work with but you can only bend it the one way. That may or may not be the way you need :)

Have a look on aliexpress, there are all sorts of different configurations. Any old Arduino should be able to run 250+ lights with a good refresh rate using this method.

On paper, they look horrible to power but in practice they aren't that bad. Whilst they can consume 60ma each, they only do that when displaying white, any other color consumers 20ma. For your clock it sounds like you'll only ever have 3 on at once anyway, so power consumption will be tiny.

Tim.

[Peter Hardy]

I've been using these SparkFun WS2812 LEDs a fair bit. They're great to work with, but to be honest if you're talking about 180 of them the price is a bit scary. Maybe you'd consider using a single ring of 60, and just using a different colour for each hand? Combined with a digital display in the centre it shouldn't be hard to deduce what the colours mean.

Wiring up addressable LEDs isn't too bad. For this you could laser cut a clock face design and glue the LEDs in place. Connect all of the +5V legs together, then all of the ground legs together so they're all powered in parallel from a 5V supply. Then start at one end and connect DOUT from the first LED to DIN on the second, and so on. DIN on the first LED connects to the signal pin on your Arduino.

I did this recently for a grid of 24 LEDs to make an annunciator panel. The back doesn't look too scary. Red for positive voltage, black for earth, and the blue wire is the signal line.

[Peter Hardy]

The way to do it with regular LEDs would be with MAX7219 driver ICs. A single MAX driver can handle 64 LEDs, so it kind of makes sense to have each driver control a single ring. And they can be daisy-chained together, so you'll end up driving all 180 LEDs from a single pin of your arduino.

The most confusing part of dealing with these is that your LEDs form a logical grid. Translating that to LEDs physically arranged differently is a bit of a challenge - you'll want to spend some time breadboarding different arrangements of 8 or 16 lights to get a feel for how it needs to be wired.

On 2015-10-08 19:38, Zachary Austin wrote:

[tALSit de CoD]

Another recommendation is an LED driver like this:

http://www.ti.com/product/tlc5916

It's daisy chainable, meaning you can just keep adding units to the end. The data is shifted in on two pins: data and clock, abs you can shift in the data for all 180 LED's and then strobe the load pin to change the output of all the LED at the same time. Do you only need 3 control pins.

Also, by sending special commands, you can change the brightness of the LEDs. The voltage for the LEDs can be different from your Arduino.

It's a neat little chip.

[Zachary Austin]

I am thinking about not using RGB LED's at all and just picking a colour for each variable and "that's how it is". That way I would only have to be driving one channel per LED. Then using a matrix LED driver.

Kind Regards,

Zac Austin

zac.au...@gmail.com

0457 574 887

[Zachary Austin]

Is there a similar chip like the TLC5916 but with 16 or 32 channels that would work with arduino? Or am I better off using more 8 channel IC's. I don't mind if it's an SMD or through-hole package. 

[Jason Lewis]

I used these which have 24 outputs

https://www.adafruit.com/products/1429

But for your application I think individually addressable LEDs would be the way to go

Jason

[Zachary Austin]

The price for 180 LEDs scares me a bit.

With the led strips, I want to have each circle show as like a progress bar not just one LED on for where the hand is, sorry if anyone misunderstood. So if I did that with the strips I would be drawing too much current. 

[Tim]

Something like this, with a 3-5 amp supply will be plenty. I wired almost 10,000 of these LEDs into a costume and it ran on a 20A fuse and single cell lipo (4v) (if I tried to make them all white for more than half a second then it blew the fuse but it was fine with any other colours.)

http://www.aliexpress.com/store/product/100pcs-string-DC5V-WS2812B-addressable-rgb-full-color-pixel-light-5cm-wire-spacing-with-transparent-wire/701799_32344693889.html

[Zachary Austin]

With these LED strips would I be able to remove the existing spacing wires and resolder shorter wires in between the LED's?

[Tim]

If you hated life :)

You can buy those little breakouts unsoldered as well.

[kr...@sleepingplanet.com]

yeah, you could get smd (not as scary as you think)

or thruhole

http://www.aliexpress.com/store/product/APA106-F5-5mm-round-hat-RGB-LED-with-APA-106-chipset-inside-full-color-frosted/701799_2043991484.html

180 will cost you $35 and give you 20 spare.

having said that, i havn't used apa106 which has the awkward timing thingy that the ws ones have.

but the arduino addressable library still supports them AFAIK

 

or you could got the classic ws2812 style, 200 for $30

http://www.aliexpress.com/item/10-1000pcs-WS2812B-4pins-5050-SMD-Black-White-version-WS2812-Individually-Addressable-Digital-RGB-LED-Chip/32453497583.html?spm=2114.01020208.8.5.NrBPCc

we have a solder oven at the space. if i can use it then anyone can.

 

Kris

[Iain Chalmers]

If you're interested in SMD parts...

I impulse-bought a spool of 1000 WS2812Bs a while back:

http://www.aliexpress.com/item/100pcs-lot-WS2812B-4pins-5050-SMD-W-WS2811-Individually-Addressable-Digital-RGB-LED-Chip-5V/32312332642.html?s=p

They're tiny - 5mm square with four 1mm solder pads.

You're welcome to a couple of hundred of them if you're likely to use them for something cool. 

big

"I say we take off and nuke the entire site from orbit.
That's the only way to be sure." - Ellen Ripley

[Zachary Austin]

On a slightly unrelated topic, how would I go about prepering a CAD drawing for the laser cutter at the space? Looking for a front plate for the clock.

Thanks

[Kris]

Yup, inkscape.
Do everything on the root layer
Ungroup everything at the end
Export to dxf.
The laser cutter will read that.

Of if you want fancy, John Slee recommends I think
http://www.frontpanelexpress.com/
But it might be another company

Sent from my Android device with K-9 Mail. Please excuse my brevity.

[Dr Hugh]

These might interest you.  Don't know if you can get rings with other than 12 LEDs

http://www.ebay.com/itm/311427175662?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT

[Dr Hugh]

[Madox]

The price of 180 WS2812's would probably be $25-$35 shipped, a custom full size PCB might be $100-300...

The pre-wired PCB versions are good if you can live with a bezel to hide the extra wiring.

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Kind Regards,

Zac Austin

zac.au...@gmail.com

0457 574 887

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[Paul]

+1 for pre-soldered ws2812 modules.
Those wires are quite thick (I have a 12cm version), I'd glue small boards onto acrylic and hide wires in the holes between the led positions. Another layer of acrylic on top would cover the wires but not the leds.

[Paul]

Having said that,
Zac, instead of copying that guy you should one-up him. Take 3 loops of electroluminescent wire and use steppers to rotate some kind of curtain above it.
http://www.aliexpress.com/item/Free-shipping-10-color-package-Electroluminescent-5M-EL-Wires-with-Battery-Box-Kit-for-Car-Bicycle/1992524794.html?spm=2114.01020208.3.12.nyFBHc&ws_ab_test=201556_3,201527_3_71_72_73_74_75,201560_1

[Zachary Austin]

Thanks but just for now I would like to stick to something a bit simpler. I might have a go at something like that a bit later on. Thanks anyway Paul :-)

I think for now, I will just stick with using a multiplexing IC. So far the MAX7219 driver ICs have stood out for me. I would be able to have one chip driving each circle as Peter suggested. It would mean I would have to do a fair bit of soldering but I don't mind that much. If I go down the multiplexer path then I will just use single colour LED's (probably just from Jaycar). I will probably purchase this kit from TronixLabs and just put the matrix display aside.

Thanks everyone for your ideas and support with this project!

Zac :-)

[Zachary Austin]

How big are the pieces of timber at the space for use in the laser cutter? I have made the outline of the base that holds the LED's. The outline circle is 292mm. Is that too big for the timber available?

Thanks

[Patrick Barnes]

The bamboo sheets are almost 300mm by almost 400mm.
(almost; because the measurement of each sheet might not quite reach that perfectly, and the edge isn't always perfect. Allow 2-3mm room in your design)

-Patrick

On 11/10/2015 12:02 PM, Zachary Austin wrote:

How big are the pieces of timber at the space for use in the laser cutter? I have made the outline of the base that holds the LED's. The outline circle is 292mm. Is that too big for the timber available?

Thanks

[Zachary Austin]

Thanks. Will check my design this afternoon. 

:-)

[Zachary Austin]

Hey guys,

Planning on coming to the space today after school, does anyone know what time the space will open today? 

Thanks