Auxiliary Functions

This feature is firmware versions 4.0 and higher. In Copter versions before 4.0 similar functions were implemented using the CHx_OPT parameters. See Auxiliary Function Switches (3.6 and earlier) page.

This page describes how to set up additional features which can be invoked from the transmitter’s auxiliary function switches.

Configuring which transmitter channel is used

Any RC input channel can be assigned any auxiliary function. However, the RC channel should not be used by any other function, such as flight mode selection or flight controls. By default, channels 1-4 are used for flight controls, channel 8 is used for flight modes in Plane and Rover, as is channel 5 in Copter.

Assigning the Feature

The RCx_OPTION parameters control these features. For example, the RC7_OPTION parameter controls which feature is assigned to RC input 7. Each RC channel has its own RCx_OPTION parameter that can be accessed in the full parameter list.

Supported Features

RCx_OPTION value Feature Description Copter Plane Rover
0 Do Nothing (Default) X X X
2 FLIP mode X    
3 SIMPLE mode (Copter) X    
4 RTL mode X X X
5 Save Trim X   X
7 Save Waypoint X   X
9 Camera Trigger X X X
10 Rangefinder X    
11 Fence X   X
12 ResetToArmedYaw      
13 SUPERSIMPLE mode X    
14 Acro Trainer X    
15 Sprayer X    
16 AUTO mode X X X
17 AUTOTUNE mode X    
18 LAND Mode X    
19 Gripper X    
21 Parachute Enable X    
22 Parachute Release X    
23 Parachute 3 Pos Switch X    
24 Reset Auto Mission to start X X X
25 Attitude Controller FF X    
26 Attitude Controller AccLim X    
27 Retract Mount X    
28 Relay 1 On/off X X X
29 Landing Gear X X  
30 Lost Vehicle Sound X X X
31 Motor Emergency Stop X X X
32 Motor Interlock X    
33 BRAKE mode X    
34 Relay 2 On/Off X X X
35 Relay 3 On/Off X X X
36 Relay 4 On/Off X X X
37 THROW mode X    
38 ADSB Avoidance Enable X    
39 Precision Loiter X    
40 Object Avoidance X   X
41 Arm Disarm X X X
42 SMARTRTL mode X   X
43 Inverted Flight X X  
46 RC Override Enable X X X
47 Rsvd for custom function X    
48 Rsvd for custom function X    
49 Rsvd for custom function X    
50 Learn Cruise     X
51 MANUAL mode   X X
52 ACRO mode X   X
53 STEERING mode     X
54 HOLD mode     X
55 GUIDED mode X X X
56 LOITER mode X   X
57 FOLLOW mode X   X
58 Clear Waypoints X X X
59 SIMPLE mode (Rover)     X
60 ZIGZAG mode X    
61 ZIGZAG mode - Save Waypts X    
62 Compass Learn X X X
63 Sailboat Tack     X
64 Reverse Throttle   X  
65 GPS Disable X X X
66 Relay 5 On/Off X X X
67 Relay 6 On/Off X X X
68 STABILIZE mode X    
69 POSHOLD mode X    
70 ALTHOLD mode X X  
71 FLOWHOLD mode X    
72 CIRCLE mode X X  
73 DRIFT mode X    
74 Sailboat Motor 3Pos Sw     X
75 Surface Tracking Up/Down X    
76 STANDBY mode X    
77 TAKEOFF mode   X  
207 Mainsail (Sailboat)     X

Description of Features

Note

in descriptions below, LOW and HIGH for a channel refers to PWM <1200us and >1800us, respectively.

Mode Switches

Any feature ending with “mode” provides the ability to switch the vehicle into that mode by setting the RC channel to high. Lowering it back to low, will return the flight mode to whatever is set on the flight mode channel.

Note

If mapped to a three-position switch then the SUPERSIMPLE mode function will allow SUPERSIMPLE and SIMPLE modes to be enabled using the high and middle switch positions, respectively (a two-position switch will enable/disable SUPERSIMPLE mode only). See here for more details .

Other functions are:

Option Description
Flip

Vehicle will flip on its roll or pitch axis depending upon the pilot’s roll and pitch stick position. See Flip Mode .

Save Trim

In Rover,a high saves the current steering channel trim, see Save Steering Trim . In Copter, it adjusts the vehicle level position using the current roll and pitch stick inputs. See details here .

Save Waypoint Save the current location (including altitude) as a waypoint in the mission. If in AUTO mode no waypoint will be saved, instead the vehicle will RTL
Camera Trigger

Camera shutter will be activated. See more details here.

Range Finder

RangeFinder is disabled when switch is in low position, enabled when in high position.

Fence Fence is disabled when switch is in low position, enabled when it high position.
Acro Trainer

Turn on automatic leveling in the ACRO flight mode.

Sprayer

Turn on the crop sprayer when switch is pulled high.

Gripper

Operates the gripper. Switch pulled low releases the gripper, high closes or grabs.

Parachute Enable

Enables the automatic release of the parachute (this does not immediately trigger the release).

Parachute Release

Immediately triggers the release of the parachute as long as the vehicle is not landed or too low.

Parachute 3Pos

Switch pulled low disables the parachute. Switch in middle enables the parachute for automatic release. Switch pulled high triggers release of the parachute as long as vehicle is not landed or too low.

Mission Reset

Reset AUTO to run the first mission command in the command list.

AttCon Feed Forward Turns on/off attitude controllers feed forward. For developers only.
AttCon Accel Limits Turns on/off attitude controller acceleration limits. For developers only.
Retract Mount

Move the camera mount to its retracted position.

Relay On/Off

Switch pulled low turns off the first relay, pulled high turns on the first relay.

Landing Gear

Deploys or Retracts Landing Gear

Lost Vehicle Alarm

Plays the lost copter alarm though the buzzer

Emergency Stop Motors

Stops motors immediately (video)

Motor Interlock

Opposite of Emergency stop (above) in that switch must be ON for motors to spin (video).

Brake

Invokes the Brake flight mode when switch goes high. Bringing switch back to low will return the vehicle to the mode indicated by the ch5 flight mode switch.

Relay2 On/Off

Switch pulled low turns off the second relay, pulled high turns on the second relay.

Relay3 On/Off

Switch pulled low turns off the third relay, pulled high turns on the third relay.

Relay4 On/Off

Switch pulled low turns off the fourth relay, pulled high turns on the fourth relay.

Throw

Invokes the Throw flight mode when switch goes high. Bringing switch back to low will return the vehicle to the mode indicated by the ch5 flight mode switch.

ADSB-Avoidance

When switch is high, ADSB avoidance (avoidance of manned aircraft) is enabled, otherwise its disabled

Precision Loiter

Turns on/off Precision Loiter. I.e. holding position above a target in Loiter mode using IR-Lock sensor.

Object Avoidance

When switch is high, avoid objects using Lightware SF40c or TeraRanger Tower. When low, object avoidance is disabled.

Arm/Disarm

Arms the vehicle if the switch goes high (subject to arming checks). Disarms the vehicle if brought low.

Inverted Flight

Enabling inverted flight only changes how ArduPilot stabilizes the vehicle. It will stabilize it with a roll of 180 degrees from normal whenever inverted flight is enabled in a stabilized mode. Unless the vehicle is capable of inverted flight, do NOT use this option.

RC Override Enable

This is a 3 position switch which enables (high) or disables (low) the use of RC overrides from the Ground Control Station.

Learn Cruise

This starts the cruise speed and throttle learning sequence on Rover when switched to high. See Tuning Speed and Throttle .

Clear Waypoints

Clears currently loaded mission waypoints.

Compass Learn

Inflight compass offset learning. See Automatic Offset Calibration section of Advanced Compass Setup .

Sailboat Tack

Any high to low, or low to high change on this channel will start a tack with opposite direction to the last tack. See Sailboat Configuration and Setup .

Reverse Throttle

When switched high, forces throttle reverse in Plane for steepening descents. Normally, this is controlled by flight mode via the USE_REV_THRUST parameter. See Automatic Landing for more information on setup of reverse thrust.

GPS Disable

Simulates GPS failure by disabling GPS.

Relay 5 On/Off

Switch pulled low turns off the third relay, pulled high turns on the fifth relay.

Relay 6 On/Off

Switch pulled low turns off the third relay, pulled high turns on the sixth relay.

Sailboat Motor 3Pos Switch

This three position switch controls the Sailboat motor. Motor is always used when high, never used when low, and as needed, otherwise.

Surface Tracking Up/Down

This three position switch determines if surface tracking via rangefinder is toward the ground (low) or ceiling (high), or disabled, otherwise.

Standby

This puts the autopilot control loops into a soft standby mode so that a parallel, redundant autopilot or companion computer can assume control of the vehicle. The PID loops, position, altitude controllers are modified such that the autopilot can smoothly resume control of the vehicle when standby is subsequently disabled. Switching of outputs or other peripherals must be done by external circuitry.

Mainsail

This RC channel will drive the output of the MainSail output ( SERVOx_FUNCTION = 89) instead of being set from the Throttle Input channel (useful if it has an auxiliary motor using that input). See Sailboat Configuration and Setup for more information about the main sail setup.

Check the channel range

../_images/aux-switch-check.png

The configured feature will be triggered when the auxiliary switch’s pwm value becomes higher than 1800. It will be deactivated when the value falls below 1200.

You can check the pwm value sent from the transmitter when the switch is high and low using the Mission Planner’s Initial Setup >> Mandatory Hardware >> Radio Calibration screen. If it does not climb higher than 1800 or lower than 1200, it is best to adjust the servo end points in the transmitter.