OpenPPS - PPS in a Box
I’ve found that making an enclosure for an electronics project is often the most difficult part and this project was no exception! But 3D printing makes this a bit more fun if nothing else.
I’m using the very impressive M5Stack as the host ESP32 processor. It has a a TFT display and 3 buttons and a good API to manage those features so it’s perfect for implementing a user interface for a project like this. It also has a micro SD card holder which has been very useful for logging test data. I am using its default “stack” which contains a small LIPO battery and pin headers for connections. I intend to replace that with the prototype board “stack” as I don’t need the battery and the pin headers when it is packaged like this.
The power supply is from Aliexpress and uses an 18650 LIPO battery as you can see. This is the only power supply that I could find so far that will still supply power even when the battery is being charged. This is pretty much essential for this application where it needs to be able to switch on and off from battery power without interrupting power to the system or causing a reset.