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 or from external buttons.

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 (i.e. roll, pitch, throttle, and yaw). The default flight mode channel is 8 for Plane and Rover and 5 for 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

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

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

X

X

21

Parachute Enable

X

22

Parachute Release

X

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

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 (4.1 and before)

X

X

X

42

SMARTRTL mode

X

X

43

Inverted Flight

X

X

44

Winch Enable

X

45

Winch Control

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

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

78

RunCam Control

X

X

X

79

RunCam OSD Control

X

X

X

80

Viso Align

X

81

Disarm

X

X

X

82

Q_Assist 3Pos Sw

X

83

ZIGZAG Auto

X

84

AIRMODE(not a flight mode)

X

X

85

Generator

X

X

X

86

Non Auto Terrain Follow Disable

x

87

CROW Mode Switch

X

88

Soaring Enable

X

89

Force Flare

X

90

EKF Position Source

X

X

X

91

Airspeed Ratio Calibrate

X

92

FBWA Mode

X

94

VTX Power

X

X

X

95

FBWA_TAILDRAGGER

X

96

MODE_SWITCH_RESET

X

X

X

97

WindVane home dir offset

X

102

Camera Mode Toggle

X

X

X

105

GPS Disable Yaw (testing only!)

X

X

X

106

Disable Airspeed Use

X

X

X

107

Enable Autotuning

X

108

QRTL Mode

X

112

SwitchExternalAHRS

X

X

X

150

CRUISE Mode

X

151

TURTLE Mode

X

152

SIMPLE mode heading reset

X

153

ARM/DISARM (4.2 and higher)

X

X

X

154

ARM/DISARM with AIRMODE on

X

X

155

TRIM RC/SERVO Save

X

X

156

Torqeedo Error Clear

X

157

Force FBWA Long FS Action

X

158

Optflow Calibration

X

X

159

Force Flying State

X

160

WeatherVane Enable

X

161

Turbine Start (Heli)

X

162

Auto Throttle Notch Setup

X

X

163

Mount Lock

X

X

X

164

Pause Streaming Logging

X

X

X

165

ARM/Motor Emergency Stop

X

X

X

166

Camera Record Video

X

X

X

167

Camera Zoom

X

X

X

168

Camera Manual Focus

X

X

X

169

Camera Auto Focus

X

X

X

170

QSTABILIZE mode

X

171

Compass Calibration

X

X

X

172

Battery MPPT Enable

X

X

X

173

Plane AUTO Landing Abort

X

174

Camera Image Tracking

X

X

X

175

Camera Lens

X

X

X

176

VTOL Fwd Throttle disable

X

Intended as continuous PWM range control inputs:

RCx_OPTION value

Feature Description

Copter

Plane

Rover

201

ROLL Input

X

X

X

202

PITCH Input

X

X

X

203

THROTTLE Input

X

X

X

204

YAW Input

X

X

X

207

Mainsail

X

208

Flap Control

X

209

Forward Throttle

X

210

Airbrakes

X

211

Walking Robot Height

X

212

Mount1 Roll

X

X

X

213

Mount1 Pitch

X

X

X

214

Mount1 Yaw

X

X

X

215

Mount2 Roll

X

X

X

216

Mount2 Pitch

X

X

X

217

Mount2 Yaw

X

X

X

300-307

Scripting RC channels

X

X

X

Note

201-204 are not implemented, reserved for future use.

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. You can have multiple “mode” option switches and more than one can be high at a time. The last “mode” change switch will determine the current mode, as well as any change of the normal mode switch.

For example, if you have a “LOITER mode” switch active and then an “AUTO mode” switch is switched high, the mode will change to AUTO. Changing the normal flight mode switch will again change the mode to the new flight mode setting, even though both RCx_OPTION mode switches are high. Lowering an active RCx_OPTION mode switch back to low will return the flight mode to whatever is set on the flight mode channel, but only if the current mode matches the mode set by that switch. Otherwise, it will have no effect.

Note

Copter and Rover mode changes are not guaranteed. They may be denied if the conditions required for that mode are not met. For example, changing to LOITER mode in Copter would fail if the GPS lock is not active, whereas in Plane the demanded mode will change and operate as best as it can.

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

The 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,
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

The camera shutter will be activated.
See more details here.

Range Finder

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

Fence

Fence is disabled when the switch is in a low position, and enabled
when in a high position.

Acro Trainer

Turn on automatic leveling in the ACRO flight mode.

Sprayer

Turn on the crop sprayer when the 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.
The switch in the middle position enables the parachute for
automatic release. The switch pulled high triggers the release of the
parachute as long as the 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 1 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 through the buzzer

Emergency Stop Motors

Stops motors immediately (video)

Motor Interlock

Motor Interlock controls the way the heliRSC (motor throttle control)
output is generated in Traditional Helicopters and HeliQuads. If
>1200us, it enables the Motor Interlock function, below it is disabled.
When <1200us, it is similar to what is sometimes referred to as
Throttle Hold in RC Helicopter terminology.
For Mulit-copters, it is used as a motor stop function when <1200us.

Brake

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

ADSB-Avoidance

When the switch is high, ADSB avoidance
(avoidance of manned aircraft) is enabled, otherwise it’s 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 the switch is high, avoid objects using Lightware SF40c
or TeraRanger Tower. When low, object avoidance is disabled.

Arm/Disarm(4.1 and earlier)

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

Option

Description

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.

Winch Enable

Enables Winch operation. The switch in the low position on this
channel relaxes the winch.

Winch Control

Controls the speed and direction of the winch. Low: takeup,
Middle: stop, High: unreel

RC Override Enable

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

Learn Cruise

This starts the cruise speed and the 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 in the 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
the 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 3-position switch controls the Sailboat motor. The motor is
always used when high, never used
when low, and as needed, otherwise.

Surface Tracking Up/Down

This 3-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, and altitude controllers are modified
such that the autopilot can smoothly resum 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.

RunCam Control

Allows starting and stopping video recording of compatible
RunCam cameras. See RunCam Camera Support.

RunCam OSD Control

Enables control of RunCam cameras OSDs.

VISO Align

Aligns external Visual Odometry with current autopilot AHRS

Disarm

Disarm the vehicle unconditionally and immediately. Unlike
Emergency Stop Motors, which waits for DISARM_DELAY
in Copter.

Q_Assist 3Pos SW

Low: disable Q_Assist entirely, Middle: Normal Q_Assist
operation, High: Q_Assist active at all times. See Assisted Fixed
Wing Flight section of Flying a QuadPlane.

ZigZag Mode Auto Enable

Enable automatic zigzag and sprayer in ZIGZAG mode.

AIRMODE(not a flight mode)

Enables and disables AIRMODE feature. See AirMode

Generator

Mode control for Richenpower Hybrid Power Generator

Non Auto Terrain Follow Disable

Disables Terrain Following in CRUISE and FBWB modes

CROW Mode Switch

Selects between different CROW aileron operating modes

Soaring Enable

Enables Soaring function operating modes

Force Flare

Moves tilt motors to the upright position and optionally sets
pitch for flare when landing Tilt Rotor QuadPlanes.
Middle: The pilot retains pitch control during a flare.
High: Pitch set to LAND_PITCH_DEG. Allows switching

EKF Position Source

between up to three source sets manually for EKF3 (only).

Airspeed Ratio Calibrate

Activates calibration of airspeed ratio in flight. Best results
occur while executing course changes over 360 degrees over
time, as in LOITER mode. See Calibrating an Airspeed Sensor.

VTX Power

Allows reading up to a 6-position switch for controlling Video
Transmitter Power. See Video Transmitter Support.

FBWA_TAILDRAGGER

Enables FBWA taildragger takeoff mode using elevator to
hold tail on the ground until airspeed is reached

MODE_SWITCH_RESET

Forces mode switch to be re-read.

WindVane home direction offset

This is a continuous input channel providing a -45 to +45
degree offset of the initial wind direction when using

Camera Mode Toggle

Toggle camera mode (Photo/Video/etc.). Ideally, this should be
on a momentary switch since only low to high transitions
toggle the camera mode. Used only with Solo gimbals
presently.

GPS Disable Yaw

Disables yaw for testing (advanced users only!)

Disable Airspeed Use

Forces Airspeed Use to be disabled for testing in the air.

Enable Autotuning

Allows tuning without entering AUTOTUNE mode. (i.e. if you
place the vehicle in LOITER/AUTO with stick mixing enabled,
it can autotune while the vehicle is loitering by using sticks,
but enabling autotuning can occur in any mode other
than MANUAL.)

SwitchExternalAHRS

If EKF3 and an external AHRS module are enabled, high on this
switch switches from EKF3 to the external AHRS

SIMPLE mode heading reset

Resets original heading reference to current heading
for SIMPLE Mode.

ARM/DISARM (4.2 and higher)

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

ARM/DISARM with AIRMODE on

Arms the vehicle if the switch goes high (subject to arming
checks) with AIRMODE active. Airmode RC option switch can
subsequently enable or disable if it is configured. Disarms
the vehicle unconditionally if brought low.

TRIM RC/SERVO Save

Saves current RC input trim and SERVO output trim for pitch,
roll, and yaw in Plane and for Steering in Rover.

Torqeedo Error Clear

Clears error condition in Torqeedo motor controller.

Force FBWA as Long FS Action

Forces mode change to FBWA in Long FS, overriding the
FS_LONG_ACTN parameter value for emergency
landings beyond RC control range to prevent normal
failsafe action from occurring.

Optflow Calibration

Enables calibration of optical flow parameters.

Force Flying

Disables the landing detection heuristic to prevent false
landing detections during a mission or manual flight
if sudden Z changes can occur due to wind gusts, etc.

WeatherVane Enable

Enables or disables weathervaning in Quadplane VTOL modes.

Turbine Start (Heli)

When armed and RSC is idle, the high position signals the
helicopter rotor speed governor to ramp the throttle to full and
back to idle, which signals the turbine engine ECU to
initiate the start sequence. The switch must be set back low and
the aircraft has to be disarmed to re-enable this feature.

Auto Throttle Notch Setup

Allows automatic setup of throttle notch parameters. Set
FFT_ENABLE =1, takeoff with switch low,
hover 30 seconds with switch high,switch low, and land and
notch parameters will have been configured.

Mount Lock

If high, locks the heading of all mounts to earth-frame,
otherwise, yaw is heading locked to vehicle heading.
If pilot controlled positioning is active, the pilot’s inputs changes
the heading target appropriately in whatever frame is selected.
Without this switch,it’s vehicle heading.

Pause Streaming Logging

If high, will not log streaming type log messages (sensors,
attitudes, EKF, etc.) to allow logging only when desired
for autopilots with limited logging capabilities
(i.e. no SD card). Events, mode changes, etc. are still logged.
Logging is unaffected if the switch is low.

ARM/Motor Emergency Stop

Three position switch. If high, will request arming. If switched to
low position, will emergency stop any rotating motor output
like the Motor Emergency Stop switch. If switched to middle
position,will de-activate the Motor Emergency Stop, but not
request an arm condition. This is a safer alternative to
ARM/DISARM in that accidental switching to low position
will not disarm, and will allow recovery in the air if
switched back to middle or high quickly.

Camera Record Video

Controls video recording on some cameras/mounts.

Camera Zoom

Controls camera zoom on some cameras/mounts.

Camera Manual Focus

Changes manual focus on some cameras/mounts.

Camera AutoFocus

Controls autofocus on some cameras/mounts.

Compass Calibration

Switching to high will behave the same as if the Start button
been pressed. Returning the switch to low will cancel the
calibration if still in progress.

Battery MPPT Enable

Enable the Packet Digital MPPT solar panel power monitor

Plane AUTO Mode Landing Abort

If switched to the HIGH position, will abort any landing that
is currently in progress while in AUTO mode.
This includes the VTOL, or fixed wing,
landing phase of any AUTO mission, and the PAYLOAD_PLACE
mission command. It does not affect the fixed wing
approach phase of a VTOL landing, QLAND or QRTL modes.

Camera Image Tracking

Activate Camera Image Tracking (only supported by ViewPro camera gimbals)

Camera Lens

Select the active camera lens (only supported by ViewPro camera gimbals)

VTOL Fwd Throttle disable

Overrides use of forward throttle in VTOL modes

ROLL Input

ROLL input channel. (replaces RCMAP)

PITCH Input

PITCH input channel. (replaces RCMAP)

THROTTLE Input

THROTTLE input channel. (replaces RCMAP)

YAW Input

YAW input channel. (replaces RCMAP)

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.

Flaps

This RC channel provides manual control the amount of FLAP
deflection and can also be used in conjunction with
(Replaces the old FLAP_IN_CHANNEL parameter)

Forward Throttle

Manual forward motor throttle in QSTABILIZE, QACRO, and
QHOVER modes

Airbrakes

Controls deployment of Airbrakes

Walking Robot Height

Input channel for Walking Robot Height. See Walking Robots.

Mount1 Roll

1st camera gimbal’s roll control

Mount1 Pitch

1st camera gimbal’s pitch control

Mount1 Yaw

1st camera gimbal’s yaw control

Mount2 Roll

2nd camera gimbal’s roll control

Mount2 Pitch

2nd camera gimbal’s pitch control

Mount2 Yaw

2nd camera gimbal’s yaw control

Scripting RC channels

Allows reading a dedicated RC channel for script inputs

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 endpoints in the transmitter.