Open-source smart battery firmware targeting the ATtiny84 platform
This started as a soft fork of iam4722202468's ThinkpadBattery project, but after sending a few pull requests I decided to do a (more or less) complete rewrite.
Like ThinkpadBattery, OpenSmartBattery is still significantly lacking in basic functionality and should be considered alpha or pre-alpha in its current state. I will continue adding features when time allows. Pull requests are welcome!
Configuration of most values is done in lib/OpenSmartBattery/config.hpp. config::HardwareConfig::Pins should give you a good idea of the hardware configuration needed until I get around to writing a guide.
You will also need to implement the specific authentication proceedure that your battery needs in lib/OpenSmartBattery/authentication.hpp (there is an implementation of the SHA-1 method there if you need it).
This project it set up to use VSCode + PlatformIO for building and deploying the firmware. As such, you will need VSCode and the PlatformIO extension to build it without some work on your own. I will not provide support for building using other methods, as this method is the easiest to maintain.
You'll need to download these files from cryptosuite2 and put them in lib/SHA/ in order to use the existing SHA-1 authentication implementation. cryptosuite2 is needed because most modern batteries use SHA-1 hashing to validate their authenticity. Older batteries simply transmit the unlock code instead of doing a signing proceedure.
I recommend developing on a more forgiving Arduino device like a Uno or Mega before flashing to your ATtiny84, as it makes it far easier to debug your code.