Compatible Radio Control Systems

This article provides an overview of the RC Transmitter and Receiver Systems that can be used with ArduPilot autopilots.

Overview

ArduPilot autopilots are compatible with:
  1. PPM-Sum receivers
  2. SBus receivers
  3. IBUS receivers
  4. Spektrum DSM, DSM2, and DSM-X Satellite receivers
  5. SRXL version 1 and version 2 receivers
  6. Graupner SUM-D

All of the above methods utilize a single serial signal transmission wire for all channels. For traditional single-wire-per-channel (PWM) receivers, a PPM encoder can be used to convert the receiver outputs to PPM-Sum.

Connecting the Receiver

ArduPilot auto-detects the protocol of the RC receiver system. For most autopilots there is a pin labeled RCin or SBus input to which the output from the receiver is connected. On many closed source autopilots, other pins are used and are detailed in their board documentation, linked from the ArduPilot Hardware page.

In addition, beginning with ArduPilot firmware releases 4.0 and later, any UART RX input will auto-detect the RC receiver, if the serial port protocol to 23 (for example SERIAL2_PROTOCOL for the TELEM2 UART is used).

To connect a PPM-Sum receiver or an SBus receiver to a Pixhawk, for example, plug the ground (black), power (red) and signal (usually white - orange in the diagram below) wires to the RC pins on the Pixhawk.

../_images/RCIN_connection.jpg

Tip

The parameter to enable the SBus output from the PixHawk style autopilots is BRD_SBUS_OUT . This is only to pass SBus externally to other devices, like servos. Not to connect a receiver to RCin or SBus In.

Radio Control Systems

Without integrated telemetry:

With integrated telemetry:

Multi-Protocol:

PPM encoders

A PPM Encoder will allow you to use any conventional RC receiver with only outputs for each channel. Both the new and previous versions of the 3DR PPM-Sum encoder (the linked encoder is compatible) are shown below:

../_images/PPM_cables_-_Copy.jpg

Newest 3DR PPM-Sum encoder

../_images/PPMEncoderDesc.jpg

Original 3DR PPM-Sumencoder

There are some downsides of using this encoder:

  • The PPM Encoder does require quite a bit of additional wiring to the receiver.
  • It uses quite a bit of power making it likely you will need to plug in your battery while doing radio setup with USB cable in Mission Planner.
  • The encoder also costs as much or more than several of the available PPM-Sum receivers including the FrSky Delta 8 below.

There is addition information about connecting and configuring the encoder here.

Note

If you are using this PPM Encoder it is important to know that when you are calibrating your transmitter you may need to hook up your flight battery to the autopilot because the USB port alone can’t supply enough power.