Soft-e-Safe RPi0 Power Switch

Started prototyping with a Raspberry Pi 2 and a 5V Trinket with a 74LVC245 level shifter. I needed the level shifter while I wait for my 3V Trinket to arrive.

I added a snap shot of the state diagram that walks through the start up and shutdown of the system.

Here's a short video that steps through the logic.

I've tried explaining this to my cats, but their still a bit lost on the signaling between the Trinket, the Raspberry Pi Zero, and the PowerBoost.

I plan to draw out a state diagram that shows the how the pieces interact over time.

Remove Power Switch

After looking at more details on the Adafruit PowerBoost 500 Charger, I noticed the breakout for the ENable pin. Looks like I don't need the FET power switch after all. The PowerBoost can handle the power switching. Yay!

Add Trinket

I've remove the power switch and added an Adafruit Trinket - 3.3V. That will give the project the smarts it needs.

Bigger LiPo

I increased the size of the LiPo battery from 150 mAh to 500 mAh.