[Pre-Order] Safe Shutdown Switch (PowerBoost Version) - Closed

[Camble]

@johweb Any time I've had a kernel panic it's been because I've been messing around with startup and shutdown, and corrupted my SD card. It's worth trying a new image with the latest script before ripping out any wiring.

[johweb]

OK, I'll have a try !

[HoolyHoo]

@johweb I believe If you comment out or remove the dtoverlay statement from config.txt you won't see that kernel panic but naturally the graceful shutdown will not work. What's happening is by setting that dtoverlay the pi is expecting a manual shutdown which in this case is done by the jfet. The kernel panic screenshot shows the pi trying to initiate a shutdown, wait three seconds and then sends the panic because it didn't shut down as expected. Bottom line the circuit for whatever reason is not shutting you down.

[johweb]

So, if I understand, you suggest that there's a problem with my complete wiring diagram ?

[HoolyHoo]

So, if I understand, you suggest that there's a problem with my complete wiring diagram ?

Don't know if it's your wiring or the circuit but you are getting the panic message because of what I said previously.

[johweb]

it may be a possibility. I'll try to make a diagram to show what I did...

[Camble]

What's happening is by setting that dtoverlay the pi is expecting a manual shutdown which in this case is done by the jfet.

The dtoverlay line is simply to set the keep-alive GPIO pin to high and the JFET is not responsible for the shutdown.

When the switch is in the ON position, GPIO27 is kept high by the 3.3v line. When you slide the switch to OFF, GPIO27 is pulled low by the internal pull-down set in the python script. This signals the shutdown. The JFET ensures the PowerBoost supplies the Pi until it has safely shut down.

[johweb]

Just to be sure for my build (sorry, I can't have a decent draw...) :

Safe shutdown switch
3.3V to pin 17 on pi
Shut-off to pin 13 on pi
Low bat to pin 11 on pi
Keep-on to pin 15 on pi
LBO to LBO on powerboost
EN to EN on powerboost
GND to G on powerboost

Powerboost
5V to 5V in on powerstrip
GND to GND in on powerstrip

Screen PCB
Composite to tv on pi
5V on pin 2 on pi
Gnd on Gnd on powerstrip

Pi zero
PP1 to 5V on powerstrip
PP6 to GND on powerstrip

Does it seem right ?

[Camble]

@johweb Yes.

[johweb]

OK, then I'll have a try for a fresh image !