Peripherals & Gimbal

The Peripherals tab configures the hardware that hangs off the flight controller: the GPS, the compass, a rangefinder/LiDAR for height and obstacle sensing, an optical flow sensor, a camera mount/gimbal and its shutter trigger, the notification LEDs and buzzer, and the relay outputs. It has one sub-tab per peripheral — GPS, Compass, Camera & Gimbal, Flow & Lidar, LEDs & Buzzer, Relays — so you work on one at a time, and each section only renders the parameters the connected firmware actually reports.

Note

These used to be split across two tabs that were the wrong home for them: GPS and compass sat under Config (they are attached hardware, not board settings), and the gimbal, flow/lidar, LED/buzzer and relay surfaces were sub-tabs of Servos — a gimbal is a peripheral that happens to use a servo output, a rangefinder usually has no servo output at all, and an LED strip or a relay is simply wired to the board.

With those moved, Servos has one job left — the output map and the settings that extend it — so it is a single page with no sub-tabs.

GPS and compass are documented in detail on Config and Sensors and Calibration; the rest of this page covers the sections that are unique to this tab.

Rangefinder / LiDAR

Configure a downward- or forward-facing rangefinder (the RNGFND1_* family). The driver lives in RNGFND1_TYPE — pick the backend that matches your hardware (for example LightWareI2C, Benewake, MAVLink, DroneCAN, or Analog). Rangefinders feed precision landing, terrain following, and surface tracking.

Key parameters:

  • RNGFND1_TYPE — sensor driver. Reboot after changing it.

  • RNGFND1_ORIENT — direction the sensor faces (Down for altitude/terrain, Forward for obstacle work).

  • RNGFND1_MIN / RNGFND1_MAX — the reliable distance band (m); readings outside it are treated as out of range.

  • RNGFND1_GNDCLR — distance the sensor reads when the vehicle is on the ground (its mounting height).

  • RNGFND1_ADDR — bus address for I2C sensors.

  • RNGFND1_POS_X/Y/Z — sensor offset from the centre of gravity.

Analog and PWM sensors reveal extra wiring controls only once the matching type is selected — pin (RNGFND1_PIN), transfer function, scaling, offset, and an optional power-save stop pin.

Note

Serial sensors also need their port assigned to the rangefinder protocol on the Ports & Serial tab (SERIALx_PROTOCOL = Rangefinder); I2C sensors use RNGFND1_ADDR instead. ArduPilot 4.7 moved the distance limits to metres (RNGFND1_MIN / _MAX / _GNDCLR); pre-4.7 firmware uses the centimetre forms (RNGFND1_MIN_CM / _MAX_CM / _GNDCLEAR). The section shows whichever set the connected firmware streams, never both.

Note

Only the first rangefinder instance has a section here. If you fit a second sensor, its RNGFND2_* parameters are edited from the Parameters (Expert) tab.

For the full sensor matrix and per-model wiring, see the ArduPilot Rangefinders landing page.

Optical flow

An optical flow sensor is a downward-facing camera that measures how fast the ground is moving beneath the vehicle. Fused into the EKF it gives position hold without GPS — the reason to fit one indoors or under cover.

The Optical Flow section configures the sensor. Getting flow working is a three-part job, and skipping any one of them leaves a sensor that reads fine and does nothing:

1. Select the driver. FLOW_TYPE picks the backend: PX4Flow, Pixart, Bebop, CXOF, MAVLink, 6 — DroneCAN (a HereFlow or any other DroneCAN flow node), MSP, or UPFLOW. ArduPilot 4.7 adds 10 — SITL for simulation. It is reboot-required: the driver does not load, and none of the dependent fields appear, until the flight controller restarts.

Tip

Choosing FLOW_TYPE = 6 (DroneCAN) with the CAN bus switched off is the classic silent failure — the node is on the wire, powered, and completely invisible. The section detects this and offers a one-click Enable CAN bus & reboot prompt that writes CAN_P1_DRIVER = 1 and CAN_D1_PROTOCOL = 1. See CAN & DroneCAN.

2. Give the EKF a height reference. Flow is an angular rate — radians per second of apparent ground motion. Turning that into a ground speed requires knowing how far away the ground is, so the estimator carries a terrain-height state and observes it, best of all, with a downward-facing rangefinder. Fit one and set its orientation to Down (RNGFND1_ORIENT = 25) using the section above. Height also has to be reasonable: before takeoff is detected, and while the estimated height above ground is under 0.5 m, the EKF zeroes the flow measurement outright — the camera cannot focus that close — so flow contributes nothing over the first half-metre of a takeoff.

3. Tell the EKF to use it. Nothing changes until the estimator’s source set names optical flow: EK3_SRC1_VELXY = 5 (OpticalFlow). Until then the sensor streams, the Status & Info card reads healthy, and navigation still runs entirely on GPS. Those EK3_SRC* parameters are deliberately not editable in this section — changing which sensors the estimator trusts is not a peripheral setting — so make that change from the Parameters (Expert) tab, with a snapshot saved first.

If a source is selected without the hardware behind it, ArduPilot refuses to arm with EK3 sources require OpticalFlow or EK3 sources require RangeFinder; the rangefinder form of that check specifically wants a down-facing sensor. See Arming & Pre-arm Checks for where to read those messages.

Mounting and scaling

  • FLOW_ORIENT_YAW — how far the sensor is rotated relative to the airframe, in centidegrees. A sensor whose X axis points to the right of the vehicle’s X axis takes a positive angle. Getting this wrong makes the vehicle drift at right angles to the correction it is trying to apply.

  • FLOW_POS_X / _Y / _Z — where the sensor’s focal point sits in the body frame, in metres (X forward, Y right, Z down from the origin).

  • FLOW_FXSCALER / FLOW_FYSCALER — per-axis scale corrections in parts per thousand, for variation in effective focal length between units. Each increment of 1 changes that axis’s flow reading by 0.1 %; the range is ±800. Leave these at 0 unless you are correcting a measured error — the configurator has no auto-calibration for them.

  • FLOW_ADDR — bus address, for sensor types that offer a choice.

  • FLOW_OPTIONS — bit 0 marks the sensor as roll/pitch stabilised (on a gimbal). This parameter is ArduPilot 4.7 and later; the field does not appear on 4.6 firmware, which has no equivalent.

Checking it works

The Status & Info tab grows an Optical Flow card once FLOW_TYPE is non-zero. It shows the sensor’s quality figure (0–255), the flow rate on each axis in rad/s, the current height above ground, the driver in use, and how long ago the last reading arrived — and it distinguishes no track (data arriving, quality 0 — usually a featureless or badly-lit surface) from data stopped (the sensor has gone quiet, which is a wiring or bus problem).

Slide the vehicle by hand over a textured floor at a realistic height and watch the flow rates move in the direction you moved it. A quality that collapses over plain surfaces is the sensor telling you the truth about the floor, not a fault.

For sensor-by-sensor wiring and the flight procedure, see the ArduPilot Optical Flow sensors page.

Gimbal / Mount

Configure a camera mount or gimbal (the MNT1_* family; MNT2_* for a second mount). The driver lives in MNT1_TYPE — Servo, SToRM32, MAVLink (Gremsy/AVT), Siyi, Viewpro, and the other supported backends.

Key parameters:

  • MNT1_TYPE — gimbal driver. Reboot after changing it.

  • MNT1_DEFLT_MODE — the mode the mount enters at boot and when no other targeting command is active (Retracted, Neutral, RC Targeting, …).

  • MNT1_RC_RATE — how fast RC input slews the gimbal in RC-targeting mode (0 selects angle control instead of rate control).

  • MNT1_PITCH_MIN/MAX, MNT1_ROLL_MIN/MAX, MNT1_YAW_MIN/MAX — per-axis angle limits.

  • MNT1_RETRACT_X/Y/Z and MNT1_NEUTRAL_X/Y/Z — the angles commanded in the retracted and neutral positions.

  • MNT1_OPTIONS — per-mount option flags (a bitmask).

Note

Serial gimbals also need a SERIALx_PROTOCOL assignment on the Ports & Serial tab. Servo gimbals are driven from autopilot PWM outputs instead, so they need the mount roles assigned on the Outputs & Motors tab (SERVOx_FUNCTION).

Warning

Both RNGFND1_TYPE and MNT1_TYPE are reboot-required. The driver does not load until the flight controller restarts, so a sensor or gimbal will not appear — and its dependent controls will not stream — until you reboot and re-read parameters.

For supported gimbals and their per-vendor setup, see the ArduPilot Cameras and Gimbals page.