The paparazzi controller was derived from the autopilot one. It is composed of two stacked boards.

Top board

It is the CPU board and it is common to every applications. It has two atmel mega MCUs, one mega8 and one mega128 both running at 16 MHz and one modem. This architecture allows to segregate the critical code in the mega8 and guarantee manual control even if something bad happens in the "thinking" MCU. MCUs are connected by a SPI bus with two expansion connectors (for additional sensors).

The modem is still the old CMX469 FSK 1200bps/2400/4800bps. We send its output in the audio channel of the 2.4GHz video transmitter

Bottom board

It is the "application board" and is meant to be customized. The example board in the repository has :

Radio control receiver

The RF section of a RC receiver can be tricky to build and tune. We use a commercial unit. We tap the output of the hf section to the Paparazzi controller board.

We could also use the servo driver but for now we don't need it. Our application board already has one.