The circuit described here is special in that it allows the colour of the RGB LED that is used to be controlled remotely. The circuit can be connected to a spare receiver output channel or in parallel with a channel already in use for other purposes. The colour of the RGB LED changes according to the servo position for the selected channel and according to the selected mode of operation.
At the heart of the circuit is a PIC12F675 microcontroller, which is connected to one output channel of the radio receiver: this allows it to measure the corresponding servo position.