Common power supply for boards and motors

NETMF & Gadgeteer
1

Since my project is stationary, I would like to power all boards and motors from one 12V DC 3A wall adapter and Barrel Jack connection. However, neither the GHI Power Extender or USB Client DP Module are able to power motors directly via the Motor Driver L298.

Is there a way using the Breakout TB10 Module to adapt one of the Power Extender connections to act as motor power? Is it possible to use the Power Extender to power the main board at the same time? There is little documentation on the Power Extender and the designer does not include it either.

Or do I need use something like https://numato.com/dc-barrel-jack-adapter.html? But then how would I properly split power between motors and boards?

2

I power a motor and a Fez Cerberus from a 12v automotive battery charger in my coffee roaster. - YouTube The motor is an old windscreen wiper motor and the whole lot draws about 2 amps.

If I was you I’d buy something like these [url]http://www.ebay.com.au/itm/1-PACK-5-5mm-x-2-1mm-DC-CONNECTORS-CCTV-SCREW-TERMINAL-PLUG-SOCKET-POWER-JACKS-/310555287639?pt=LH_DefaultDomain_3&hash=item484e89a057[/url] (not those ones, that supplier looks too expensive. If you’re in Australia ping me and I’ll post you some of the ones I bought). What you then need is to run two wires from each connection on a single socket over to two plugs - one for the DP module, and the other is for your motors (assuming that connection is suitable - easy to use whatever you need though !).

1 Like
3

@ Brett - Thanks, this is a very clever workaround for the prototype and I have already ordered the appropriate parts.

Long term, is there a plan to provide a common power supply for boards and motors? Or could the following components be combined:

https://numato.com/dc-barrel-jack-adapter.html?
USB Multi Voltage Power Supply | Numato Lab
https://www.ghielectronics.com/catalog/product/405

This would be used to power the main board with 3.3V and 5.0V.

Separately, power would also be fed to https://www.ghielectronics.com/catalog/product/315 from the barrel jack.

Is this a reasonable strategy?

4

I can’t comment about GHI’s commercial intent, but I wouldn’t expect to see anything specifically for power in your very specific need.

What power do you need for the motor ?

A solution here depends on how “hacky” you want things to end up. You can’t take 12v from any location on the DP module or the Power Extender module, and you can’t take it from any location on a Gadgeteer socket. So that means, to me at least, you need to provide power separation before any of these modules. Choose the simplest way - in my view, splitting the input into two outputs, one for the motor and one for the existing DP module is pretty clean (and basically what I did). You could do that with a single 2.1mm barrel jack and a 2.1mm plug like I pointed to you, then using bare second set of wires into the L298 module. You could also replace the jack with the numato one you point out, but you still need a clean way to feed power into the DP, so you’ll still need a plug.

1 Like
5

@ Brett - Thanks, I definitely agree that what you have suggested is the simplest solution. What I was asking for was how to create a less hacky solution long term.

6

What I propose isn’t hacky at all :slight_smile: .

You could create your own power supply that did all this. But in my view, you have a real easy option here and it’s not worth worrying about

1 Like
7

I have to agree with @ Brett as I don’t see this as ‘Hacky’ either. It’s simply a 12V supply feeding two items. If your project is in an enclosure you only need the one barrel connector with the split being hid away inside.