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Joystick

OpenIPC includes an experimental rcjoystick utility for using a USB joystick or an RC transmitter in USB joystick mode as an RC input source.

The tool reads Linux joystick events and sends MAVLink 2 RC_CHANNELS_OVERRIDE packets to the telemetry endpoint, commonly 127.0.0.1:14650 on the recorder. This allows more direct channel forwarding than some ground station joystick integrations, including support for up to 18 MAVLink RC channels.

When to use it

Use rcjoystick when you want the ground station or recorder to forward joystick axes and buttons directly to the flight controller through MAVLink instead of relying on Mission Planner or QGroundControl joystick handling.

Typical use cases:

  • USB RC transmitter connected to an OpenIPC ground station.
  • USB joystick connected to a recorder with Linux joystick support.
  • Forwarding RC channels to telemetry_tx or another MAVLink endpoint such as mavlink-routerd.
  • Injecting a basic RSSI-like value into a selected RC channel.

Command-line options

The utility exposes its options through rcjoystick -h:

Usage:
 [-v] verbose;
 [-d device] default /dev/input/js0;
 [-a addr] ip address send to, default 127.0.0.1;
 [-p port] udp port send to, default 14650;
 [-t time] update RC_CHANNEL_OVERRIDE time in ms, default 50;
 [-x axes_count] 2..9 axes, default 5, other channels mapping to js buttons from button 0;
 [-r rssi_channel] store rx packets per second value to this channel, default 0 (disabled);
 [-i interface] wlan interface for rx packets statistics, default wlan0;

Setup summary

The recorder needs a kernel and root filesystem with USB HID joystick support. On newer builds the hid-generic module is loaded automatically.

A typical setup flow is:

  1. Copy the rcjoystick binary to /usr/bin on the recorder.

  2. Make it executable:

    Terminal window
    chmod +x /usr/bin/rcjoystick

  3. Reboot the recorder.

  4. Connect the RC transmitter or joystick over USB.

  5. Test in verbose mode:

    Terminal window
    rcjoystick -v

If everything is working, joystick axis and switch changes should appear in the console output. In QGroundControl, check Analyze Tools → MAVLink Inspector → RC_CHANNELS_RAW to confirm that RC channel values are changing.

For persistent startup, create an init service and make sure it starts after wifibroadcast.

RSSI channel injection

rcjoystick can also write received packet statistics into a selected RC channel. This can be used as a simple RSSI-like indicator.

Example:

Terminal window
rcjoystick -r 16 -i wlan0

If the WFB interface is not wlan0, replace it with the correct interface name.

On the flight controller side, configure RSSI from RC channel 16, adjusting the high value to match your normal packet rate:

RSSI_TYPE 2
RSSI_CHANNEL 16
RSSI_CHAN_LOW 0
RSSI_CHAN_HIGH 800

Known limitation

The upstream note mentions short freezes when both sticks are moved aggressively in all directions. The issue appears to be related to missing events from the joystick driver. The workaround described there is to use an SBUS-to-USB HID joystick bridge based on Arduino Pro Micro.

Source