Power management 2 - Githubissues

washed commented 8 months ago

Schematic changes to make soft-off/on work
Added manual rpi config steps to readme

Remaining issues:

can we still reboot or are we turned off? => reboot is now possible!
test DPST switch with power bank => initial solution didn't work, but the new circuit solves this
connect switch pulled net to gpio input through some diodes to double as power off signal => no longer necessary, see schematic
this also solves a serious issue with the amp suffering a latch up if it "sees" the ramp from 5 to 12V by adding another load switch which can be controlled by software
also introduces a dedicated user for the service. Setting this up requires some manual steps on the PI! See readme!
some questions remain about the user id in the unit file. currently it is hard coded, but this might break on some systems. We probably need some pre-step to export the UID to the environment or instantiate the unit file from a template. Using %u or %U does not work, because these are not affected by the user the services application runs at, just the user that runs the service itself. Since we want the service to autostart on boot without a login, we cannot make it a --user service

Major changes to the electrical setup and required components! Rewiring is necessary! Should not affect any dev setups that are powered by a lab PSU. This is about the actual device implementation with USB decoy, power bank etc.

washed commented 6 months ago

Pretty sure we now have a good way to trigger power on and power off, just not in the way we had originally planned. We'll need another high side switch to turn the amp on after we have negotiated for 12V. The ramp from 5 to 12V causes nasty latch ups.

washed commented 6 months ago

@tmh-alex is your approve still valid after switching to a fixed UID?

tmh-alex commented 6 months ago

@tmh-alex is your approve still valid after switching to a fixed UID?

Way too simple solution, it needs to be elaborate and hard to understand!

tmh-alex commented 6 months ago

(approved)

washed commented 6 months ago

awesome, I will merge this and address some other points (noise, some more decoupling etc) in another PR

washed / drempelbox

Power management 2 #15