RE: Using an external battery supply

[Endat]

I'm writing a tutorial about powering-on external devices using the VoCore. I sent this message to Vonger a while back but maybe I can get a response faster in the forum.

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Hello!

I am trying to use gpio0 to power on/off a Raspberry Pi which has its own battery. I made 1 attempt which almost worked, but I think the VoCore sucked some of Pi's battery power. I am powering the VoCore using a sliced USB cable plugged into my computer. Here are some illustrations:



I have since fried my VoCore and cannot do any more testing until the new one arrives.. I know very little about electronics so far, but I am learning fast. I have come up with the following 2 concepts and was wondering if either of them may do what I need:





It may not be as simple as either of these, but I was hoping you could point me in the right direction. Here is a link to the PSD if you have time to correct my work. http://www.picturesloaded.com/users/endat/VoCorePiWiring.psd

Thank you!

[Greenwire-Elektronik]

You might want to read yourself into transistors, in this case a P-FET might be interessting. Also look into VoCores datasheet for maximal current can be drawn out of an GPIO pin - this explains why powering a LED is working, a PI not. Trying to power an PI via a pin might destroy the pin driver or the VoCore itself.

[Endat]

Thank you for the input! I will do some reading.

The Pi is just an initial test, eventually I want to be able to power larger things like a coffee maker or a computer.. so maybe going through the GPIO directly isnt the best choice. I have thought about using a solenoid or stepper motor to physically complete the circuit or push the power button, but I havent done any more tests since I fried the VoCore.

I should get a new one in a couple of weeks.. That should give me time to research.

[Greenwire-Elektronik]

Thank you for the input! I will do some reading.

The Pi is just an initial test, eventually I want to be able to power larger things like a coffee maker or a computer.. so maybe going through the GPIO directly isnt the best choice. I have thought about using a solenoid or stepper motor to physically complete the circuit or push the power button, but I havent done any more tests since I fried the VoCore.

I should get a new one in a couple of weeks.. That should give me time to research.

Please gimme a ping when you receive the breakout board - i just want to know how long customers have to wait for it. I have a few VoCores w/o dock here - next time it might be faster getting it via air post from here.

btt: Get rid of the Idea to drive something larger than a LED with the GPIO directly. With relays and fet transistors you have everything by hand you possibly will need

[Endat]

Looks like I had it close the first time, but can't expect the sort of power I want without some extra circuits. I've been reading about transistors and relays.

I'll let you know which day the board comes. I don't usually check my mail often, but I have been every day, Im also expecting a couple more VoCore units and some batteries with solar chargers and solar panels. One of the first things I will do with the breakout board is try to solder a female battery connector to it (unless that's what the USB connector is for).. it gives a more reliable power connection.

[Greenwire-Elektronik]

Looks like I had it close the first time, but can't expect the sort of power I want without some extra circuits. I've been reading about transistors and relays.

I'll let you know which day the board comes. I don't usually check my mail often, but I have been every day, Im also expecting a couple more VoCore units and some batteries with solar chargers and solar panels. One of the first things I will do with the breakout board is try to solder a female battery connector to it (unless that's what the USB connector is for).. it gives a more reliable power connection.

The USB connector indeed is for power supply