Cluster Hat V2.3

[Hotpoint]

I've noted problems discussed with under power indications using RPI 3B+ with the cluster hat and wondered if there was an alternative to using the micro USB to power the controller Pi.

Noticed that there is an un-soldered +5V connection point on the Cluster Hat that looks to be connect out to the GPIO header. Given a suitably regulated power supply could this back power the Hat at the same time as the controlling Pi?

Any advice would be gratefully received

Thanks

[Chris Burton]

Hi, 

I've noted problems discussed with under power indications using RPI 3B+ with the cluster hat and wondered if there was an alternative to using the micro USB to power the controller Pi.

If you use the official PSU I wouldn't expect to see any under voltage issues. Whilst PSU from other manufacturers say they're 2.5A (or even 3A) they're not always up to the job.

 

Noticed that there is an un-soldered +5V connection point on the Cluster Hat that looks to be connect out to the GPIO header. Given a suitably regulated power supply could this back power the Hat at the same time as the controlling Pi?

There's a 6 way header on the bottom and also holes for a 2 Way 3.5mm Pitch scew terminal towards the front of the board.

By default applying power to either of these will power the Cluster HAT (+Pi Zeros) and controller Pi. If you cut the PWR jumper between Rpi and the centre pad if will just power the Cluster HAT (+Pi Zeros).

Chris.

[Hotpoint]

Chris,

I'll give this a try as I'm trying to streamline the footprint and was never keen on the micro USB sticking out the side of the RPi on a headerless set-up. Especially as it was only ever rated to 60W max when run at 20 V and considerably lower at 5.x V.

A break out of the USB would be a fantastic addition to this great board.

Cheers for the advice

[Ian Goldsmith]

If your clusterhat is drawing 60w I'd suggest something is very wrong. Zero's are only meant to use about a watt, often a lot less.

... the root of all the power issues IMO is just that the 'official' power bricks aren't 5v.. they're 5.1 or 5.2v.  With adapters that are a bit over 5v to adjust for vdrop in the cables I've never seen an issue, the pi is just fussy on once its the slightest bit below.

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[philippe_44]

Hi - So with 2.3 it's not possible to power the hat through the USB plug on the controller, right? Do you have the reference of a power jack that would fit in the 3.5mm through holes nicely? I could not find any on digikey and I would prefer that rather than putting a 3.5mm term block and then having something hanging

Thanks

 

[Chris Burton]

Hi, 

Hi - So with 2.3 it's not possible to power the hat through the USB plug on the controller, right? Do you have the reference of a power jack that would fit in the 3.5mm through holes nicely? I could not find any on digikey and I would prefer that rather than putting a 3.5mm term block and then having something hanging

To power via the USB connector you need to cut the trace on the "PWR" solder jumper between "RPi" and the centre pad and then bridge the centre pad to "USB" with solder.

To use the screw terminals at the front (or SMD pads underneath you'd still need to cut the PWR trace as above).

I just use 3.5 mm screw terminals like https://cpc.farnell.com/search?st=CTB3051 so probably not what you're wanting. To connect the fan up into case for https://groups.google.com/d/msg/clusterhat/8wf8JSzwIho/BGostCi6CQAJ I used a standard 0.1" pitch 2 pin header and bent the pins to fit which might work for you.

Chris.

[philippe_44]

So I feel I'm been thick on that as well ...

Looking at the PCB trace, it seems to me that the PWR center pad (the feed) by default is joined to the Pi 40pins header +5V. Cutting it and leaving it open let power come from 3.5mm header or the a connector that could be soldered on the SMT pads underneath. Closing to it to USB means that 5V comes from the micro-USB connector on the hat. So what I'm confused on is why do the guide/video say that that you should use the small USB cable to connect between one on the Pi USB A connector to the hat micro-usb if by default the PWR connection is not connected to that hat micro-usb connector 

[philippe_44]

Crap ... I'm sorry I did not realize that the USB connector from hat to pi were just power and so to have data, you need to have this loop cable. I'll have to move away from 2A+ as having a hub on the single USB connector does not make sense

[Chris Burton]

Hi, 

Crap ... I'm sorry I did not realize that the USB connector from hat to pi were just power and so to have data, you need to have this loop cable. I'll have to move away from 2A+ as having a hub on the single USB connector does not make sense

Yeah, by default the USB cable is for power to the USB hub IC  (not the Pi Zeros) and for USB Gadget data - I probably didn't make this clear enough in the video though.

Chris.

[philippe_44]

Well, I never looked in details at the pi connector specs and I did not realize it has no HSIC interface. I'll use a 3A+ so that I have WiFi on board and use the single USB port to loop to the clusterhat