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 thepilot’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 rolland pitch stick inputs. See details here.Save Waypoint
Save the current location (including altitude) as a waypoint in themission.If in AUTO mode no waypoint will be saved, instead thevehicle will RTL.Camera Trigger
The camera shutter will be activated.See more details here.Range Finder
RangeFinder is disabled whenthe 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 enabledwhen 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 pulledlow 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 parachuteas 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 forautomatic release. The switch pulled high triggers the release of theparachute 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 asThrottle Hold in RC Helicopter terminology.For Mulit-copters, it is used as a motor stop function when <1200us.(video).Brake
Invokes the Brake flight mode when the switch goes high.Bringing the switch back to low will return the vehicle to the modeindicated 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 switchgoes high. Bringing the switch back to low will return the vehicleto 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 disabledPrecision Loiter
Turns on/off Precision Loiter.(i.e. holding position above a target in Loiter modeusing IR-Lock sensor)Object Avoidance
When the switch is high, avoid objects using Lightware SF40cor 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 stabilizesthe vehicle. It will stabilize it with a roll of 180 degrees fromnormal whenever inverted flight is enabled in a stabilized mode.Unless the vehicle is capable of inverted flight, do NOT usethis option.Winch Enable
Enables Winch operation. The switch in the low position on thischannel relaxes the winch.Winch Control
Controls the speed and direction of the winch. Low: takeup,Middle: stop, High: unreelRC 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 sequenceon 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 OffsetCalibration section of Advanced Compass Setup.Sailboat Tack
Any high to low, or low to high change on this channel will starta tack in the opposite directionto the last tack. See Sailboat Configuration and Setup.Reverse Throttle
When switched high, forces throttle reverse in Plane forsteepening descents. Normally, this iscontrolled by flight mode via the USE_REV_THRUSTparameter. See Automatic Landing for more information onthe setup of reverse thrust.GPS Disable
Simulates GPS failure by disabling GPS.
Relay 5 On/Off
Switch pulled low turns off the third relay, pulledhigh turns on the fifth relay.Relay 6 On/Off
Switch pulled low turns off the third relay, pulledhigh turns on the sixth relay.Sailboat Motor 3Pos Switch
This 3-position switch controls the Sailboat motor. The motor isalways used when high, never usedwhen low, and as needed, otherwise.Surface Tracking Up/Down
This 3-position switch determines if surface tracking viarangefinder is toward the ground (low) or ceiling (high),or disabled, otherwise.Standby
This puts the autopilot control loops into a soft standby modeso that a parallel,redundant autopilot orcompanion computer can assume control of the vehicle.The PID loops, position, and altitude controllers are modifiedsuch that the autopilot can smoothly resum autopilot cansmoothly resume control of the vehicle when standby issubsequently disabled. Switching of outputs or other peripheralsmust be done by external circuitry.RunCam Control
Allows starting and stopping video recording of compatibleRunCam 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. UnlikeEmergency Stop Motors, which waits for DISARM_DELAYin Copter.Q_Assist 3Pos SW
Low: disable Q_Assist entirely, Middle: Normal Q_Assistoperation, High: Q_Assist active at all times. See Assisted FixedWing Flight section of Flying a QuadPlane.ZigZag Mode Auto Enable
Enable automatic zigzag and sprayer in ZIGZAG mode.See 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 setspitch for flare when landing Tilt Rotor QuadPlanes.Middle: The pilot retains pitch control during a flare.High: Pitch set to LAND_PITCH_DEG. Allows switchingEKF Position Source
between up to three source sets manually for EKF3 (only).Airspeed Ratio Calibrate
Activates calibration of airspeed ratio in flight. Best resultsoccur while executing course changes over 360 degrees overtime, as in LOITER mode. See Calibrating an Airspeed Sensor.VTX Power
Allows reading up to a 6-position switch for controlling VideoTransmitter Power. See Video Transmitter Support.FBWA_TAILDRAGGER
Enables FBWA taildragger takeoff mode using elevator tohold tail on the ground until airspeed is reachedMODE_SWITCH_RESET
Forces mode switch to be re-read.
WindVane home direction offset
This is a continuous input channel providing a -45 to +45degree offset of the initial wind direction when usingWNDVN_TYPE = 2.Camera Mode Toggle
Toggle camera mode (Photo/Video/etc.). Ideally, this should beon a momentary switch since only low to high transitionstoggle the camera mode. Used only with Solo gimbalspresently.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 youplace 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 otherthan MANUAL.)SwitchExternalAHRS
If EKF3 and an external AHRS module are enabled, high on thisswitch switches from EKF3 to the external AHRSSIMPLE mode heading reset
Resets original heading reference to current headingfor SIMPLE Mode.ARM/DISARM (4.2 and higher)
Arms the vehicle if the switch goes high (subject to armingchecks). Disarms the vehicle unconditionally if brought low.ARM/DISARM with AIRMODE on
Arms the vehicle if the switch goes high (subject to armingchecks) with AIRMODE active. Airmode RC option switch cansubsequently enable or disable if it is configured. Disarmsthe 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 theFS_LONG_ACTN parameter value for emergencylandings beyond RC control range to prevent normalfailsafe action from occurring.Optflow Calibration
Enables calibration of optical flow parameters.
Force Flying
Disables the landing detection heuristic to prevent falselanding detections during a mission or manual flightif 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 thehelicopter rotor speed governor to ramp the throttle to full andback to idle, which signals the turbine engine ECU toinitiate the start sequence. The switch must be set back low andthe aircraft has to be disarmed to re-enable this feature.Auto Throttle Notch Setup
Allows automatic setup of throttle notch parameters. SetFFT_ENABLE =1, takeoff with switch low,hover 30 seconds with switch high,switch low, and land andnotch 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 changesthe 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 desiredfor 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 tolow position, will emergency stop any rotating motor outputlike the Motor Emergency Stop switch. If switched to middleposition,will de-activate the Motor Emergency Stop, but notrequest an arm condition. This is a safer alternative toARM/DISARM in that accidental switching to low positionwill not disarm, and will allow recovery in the air ifswitched 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 buttonfor onboard calibration hadbeen pressed. Returning the switch to low will cancel thecalibration 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 thatis currently in progress while in AUTO mode.This includes the VTOL, or fixed wing,landing phase of any AUTO mission, and the PAYLOAD_PLACEmission command. It does not affect the fixed wingapproach 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 MainSailoutput (SERVOx_FUNCTION
= 89)instead of being set fromthe Throttle Input channel (useful if it has an auxiliary motorusing that input). See Sailboat Configuration and Setup formore information about the main sail setup.Flaps
This RC channel provides manual control the amount of FLAPdeflection and can also be used in conjunction withAutomatic Flaps and/or flaperons.(Replaces the old FLAP_IN_CHANNEL parameter)Forward Throttle
Manual forward motor throttle in QSTABILIZE, QACRO, andQHOVER modesAirbrakes
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¶
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.