I built these electronics devices
3.3V UART Framework Expansion Card
UART interace expansion card for Framework computer.
5.0V UART Framework Expansion Card
UART interace expansion card for Framework computer.
OLED Framework Expansion Card
OLED I2C interace expansion card for Framework computer.
RS-232 Framework Expansion Card
RS-232 expansion card for Framework computer.
RS-485 Framework Expansion Card
RS-485 interace expansion card for Framework computer.
Device that follow are no longer maintained or supported (but might work regardless

UsbAmps
UsbAmps is a small USB pass-through device that measures current, voltage and power for USB 2.0 devices.
