This is an Arduino library that makes it easy to write sketches that talk to DCS-BIOS.
For more information and documentation, see the DCS-BIOS FlightPanels Project. The example "OneOfEverything" is a good place to start looking for controls to use.
DCS-BIOS was originally developed here, DCS-BIOS project. DCS-BIOS Flightpanels forked all of DCS-BIOS in order to initially provide support for Saitek Flight Panels. As of Nov, 2020, the original project has received limited support (despite a major update for HUB), and FlightPanels is gaining in popularity due to it's support. Late in 2020, this fork of the arduino-only portion was created to become the "official" branch associated with the FlightPanels DCS-BIOS side.
This is a community maintained plugin. Support is best found at the DCS-Flightpanels discord channel. The wiki is very much a work in progress, and can be found here: https://github.com/DCSFlightpanels/dcs-bios-arduino-library/wiki