Power

Published on 2017-07-04 in Ye Olde Nowt.

The ZeroLiPO module doesn’t work very well with this power-hungry display. Adding a big capacitor across the power helped somewhat, but you can still see problems when the display has a lot of white to show.

For now I’m just powering the whole thing from a 1S LiPO battery directly, without any boost converter or other circuit. That works well, due to reasons described in this project log , and I’m actually quite happy with this. However, there is no overdischarge protection, and I need to manually switch the power off after the raspberry pi shuts down – there should be a better way to do it.

So I started looking around for a ready module for that – what can I say, I’m lazy – and was quite surprised that I couldn’t find anything like that. OK, fine, I will just have to build my own. I looked around a bit for similar projects to steal from, and found this one: http://www.mosaic-industries.com/embedded-systems/microcontroller- projects/raspberry-pi/on-off-power-controller – it’s a very nice schematic, and it only uses one GPIO pin to both signal the pi to shutdown, and see when it finished. I might still make this, because it’s generally useful, but for now I have a better idea.

That project log I linked, it’s for a project that exactly fits my needs. And that project is available to buy on Tindie. It’s a battery, a charger, a touch pad button for switching it on and off, and I2C for battery monitoring and low power shutdown. It does everything I need. I will probably try to put a smaller battery in it, so that it fits the size of the pi zero better, but that’s it.