Tackling Graceful Shutdowns on the GBZ

[Felix]

I understood that so far. But how does the Pi turn on at first when there is no voltage on the ON pin of the pololu because the Pi is still off?

By the switch that's connected to the pololu, when you switch the switch on the pololu then lets the electricity through. The "ON" pin is a override pin that keeps the pololu on even when the switch is turned off.

[manzel]

Ah ok, so it does not work the other way around (the ON pin keeps the Pololu off). Then I must have done something wrong, have to recheck everything.

[Felix]

Ah ok, so it does not work the other way around (the ON pin keeps the Pololu off). Then I must have done something wrong, have to recheck everything.

No, the "ON" pin uses the 3.3v from the pi to override the switch so when the pi gets a signal to turn off it will cut off the 3.3v to the pololu and then the pololu shuts off.

[Popcorn]

Just saw all of this. Check connectivity on all your connections. Something isn't wired right. If you followed the instructions, it should work. I would check the sw and gnd and also your vout and gnd. Also try to manually bridge sw and gnd as that should turn the switch on too. Let me know how it goes.

[Felix]

Well, I've been to my hackerspace in my area and asked if it was possible to do it with mosfet and the answer was yes, because the mosfets are voltage based and not current based like the transistors, so you can just hook the gates to the pi0 output and the battery low. This is so much simpler then the pololu, the only thing is to find a n-channel depletion mosfet because there not that commonly used.

[Camble]

Well, I've been to my hackerspace in my area and asked if it was possible to do it with mosfet and the answer was yes, because the mosfets are voltage based and not current based like the transistors, so you can just hook the gates to the pi0 output and the battery low. This is so much simpler then the pololu, the only thing is to find a n-channel depletion mosfet because there not that commonly used.

Nice one, but also typical! I now have a useless Pololu

[Ganreizu]

Like these?

http://www.infineon.com/cms/en/product/ ... 6a586204b8

http://www.ebay.com/bhp/mosfet-n-channel

[Camble]

Does anyone know if n-channel MOSFETs are used in computer power supplies and such? I've got plenty stuff lying around I could cannibalise if that was the case.

[SidSilver]

You are just building your own Polulu switch

[Felix]

Like these?

http://www.infineon.com/cms/en/product/ ... 6a586204b8

http://www.ebay.com/bhp/mosfet-n-channel

What you need to look for is mosfets with a low max gate voltage so that it is easily to be overcome by the pi or the battery low one

You are just building your own Polulu switch

Not quite, if you think for a moment the powerboost is also a sort of a pololu but the on/off is different. I'm trying to do it only with the powerboost and not with the pololu.