FrSky Compatible Transmitter for Raspberry Pi

Control a RC model with an FrSky receiver using a joystick and rudder pedals connected to a Raspberry Pi single-board computer.

A CC2500 module is connected to the the Raspberry Pi using the SPI bus to send FrSky compatible signals. A USB joystick, throttle control and rudder pedals can be used for control inputs.

The FrSky transmitter code is ported from DIY Multiprotocol TX Module project.

Project status

It's possible to bind FrSky compatible receiver to FrPi and control roll, pitch, yaw and throttle using a joystick, throttle controls and rudder pedals. (Tested with a micro quad)

Demonstration of roll, pitch, yaw and throttle:

A a FrSky compatible receiver using the FRSKY_D protocol can be bound:

Todo

• Command line parameters for transmitter id, binding etc
• Configure joystick(s) from the command line
• Find out why the signal from the CC2500 module is so weak compared to a Taranis radio
• Tidy up the code
• ~~Connect Raspberry Pi to CC2500 module using SPI bus~~
• ~~Bind receiver~~
• ~~Send frequency hoping data packets from FrPi to receiver~~
• ~~Write code to receive inputs from USB joystick~~

Requirements

• Raspberry Pi single-board computers
• A CC2500 module
• USB joystick / rudder pedals

Tested with:

• Raspberry Pi Model B Rev 2
• CC2500+PA+LNA 2.4G SPI 22dBm Wireless Data Transceiver Module CC2500 Module

Setup

Install dependencies

sudo apt install git cmake wiringpi

Set up SPI bus on Raspberry Pi

sudo raspi-config

Select:

• 5.Interfacing Options
• P4 SPI
• YES
• OK
• Finish

Connect module

* GDO2 is currently not used

Build software

joystick setup is currently hardcoded in the Multiprotocol.c in the main() function.

git clone https://github.com/alexbirkett/FrPi.git
cd FrPi/src
mkdir build
cd build
cmake ..
make

Run FrPi

On the first Raspberry Pi:

From the FrPi/src/build directory:

./frpi