This library allows you to emulate FlySky's iBus telemetry sensors in the way you want (Voltage, RPM, GPS, Temperature and many others) using Arduino. It's based on interrupts, so main thread is not blocked. You can easily get values from your Arduino modules and send it to your transmitter screen! Fully supports 2 and 4 byte sensors, so you can use every one available in qba667 FlyPlus firmware. It's very simple to use. Included example is self-explaining. Enjoy!
gustavol/iBUSTelemetry-Arduino
Arduino library that allows for emulation sensors for iBUStelemetry
C++