DroneCan Airspeed Quick Start Guide(PX4)
Overview
The Holybro DroneCAN Airspeed is an industrial-grade differential pressure measurement module designed for precision airspeed measurement in various UAVs, including planes, VTOLs, and other vehicles. Equipped with DLVR_L10D digital Pressure Sensor and running ArduPilot AP-Periph Firmware, this module ensures accurate and reliable airspeed data across different flight conditions.
Features
Wide Pressure Range: Supports up to 2500 Pa and 226.8 km/h (141 mph) airspeed measurement.
High-Precision DLVR Sensor : Based on ALLSENSORS® DLVR with CoBeam technology, providing high precision and low temperature drift.
High Accuracy: Better than 1% accuracy across a wide temperature range, ensuring reliable and accurate readings in demanding application.
DroneCAN Protocol: Compatible with both PX4 and ArduPilot platforms.
Aluminum Shell: Durable and reliable construction.
Specifications
MCU: STM32G473CE, 170 MHz, 128KB RAM, 512KB Flash
Sensor: DLVR_L10D
Pressure Range: 2500 Pa
Burst Pressure: 75 kPa
Airspeed Measurement: 0-226.8 km/h
Accuracy: Error rate less than 1.0%
Firmware: AP-Periph DroneCAN
Communication Protocol: DroneCAN
Compatible Flight Controllers: Any flight controller with a CAN interface running PX4 or Ardupilot firmware
Working Voltage: 4.75~5.25V
Current Consumption: ~100mA
Dimensions: 29 x 35.5 x 16.5 mm (module), 91.5 x 28 x 30 mm (Pitot tube)
Weight: 38.3g (Includes Pitot tube and tubing)
Operating Temperature: -20 to 85℃
Pinouts
CAN port
Pin | Signal | Volt |
1（Red) | VCC | +5V Input |
2 | CAN_H | +3.3V |
3 | CAN_L | +3.3V |
4 | GND | GND |
LED Indicator
Power LED
Solid light when powered on, indicating normal voltage.
Status LED
Continuous fast blinking: MCU is in DFU mode, waiting for firmware upload.
Fast blinking for 3 seconds, then solid for 1 second: Waiting for CAN connection.
Slow blinking at 1-second intervals: CAN connection successful.
DroneCan Airspeed Quick Start Guide(ArduPilot）
The setup and configuration described in this chapter apply when using the DroneCan Airspeed with a controller board running ArduPilot firmware.
Enable
Open Mission Planner and go to the Config > FULL Parameter List tab to set the following parameters and then restart the vehicle.
//If connected to CAN1
- CAN_P1_DRIVER=1
- CAN_D1_PROTOCOL=1
//If connected to CAN2
- CAN_P2_DRIVER=1
- CAN_D2_PROTOCOL=1
//Set the airspeed sensor type to UAVCAN and enable it.
- ARSPD_TYPE=8
- ARSPD_USE=1
Airspeed offset calibration
When there is no wind and the airspeed display is greater than 3m/s, please reset the airspeed to zero before taking off.
Run Mission Planner software and connect to the flight controller
Make sure the pitot tube is in a windless environment
Open Mission Planner>Flight Data>Action Bar
Select "Preflight Calibration" in the first check box; click the "Perform Action" button on the right
Pre-flight inspection
Before flying, please connect to the ground station to check that there is no wind and ensure that the airspeed value is within the range of 0~3m/s (if it exceeds the range, need perform airspeed offset calibration)
Hold the pitot tube with your hand and blow air into the pitot tube. If the airspeed value changes according to the airflow speed, the inspection is complete.
Airspeed calibration
*Note
The airspeed ratio of different installations and individual airspeed gauges will be somewhat different. The airspeed gauge needs to be calibrated on the first flight.
//Enable automatic airspeed calibration
- ARSPD_AUTOCAL=1
Perform calibration (choose one of the following two methods)：
Method A: Lift off in QStabilize or QLoiter multi-axis mode and switch to FBWA (self-stabilizing A mode) to control the drone to fly and hover for about 5 minutes. After the ground station message bar prompts that the calibration is completed, execute the landing. With calibration's completion, set ARSPD_AUTOCAL to 0.
Method B: If you don’t know how to fly in FBWA mode, you can fly with the airspeed sensor enabled but not using it (ARSPD_USE=1; ARSPD_TYPE=8; do not fly in windy condition when performing this operation); the aircraft will fly using ground speed (relative ground speed), and use Loiter mode to hover for about 5 minutes after takeoff. When ground station message bar indicate the calibration is completed, perform landing. After the calibration is completed, set ARSPD_AUTOCAL to 0.
The setup and configuration described in this chapter applies to the DroneCan Airspeed sensor with a controller running PX4 firmware.
Enable
Run QGroundControl, set the parameters below. Restart the vehicle to save the configurations.
Set UAVCNN_ENABLE to Sensors automatic Config
Reboot
Set UAVCAN_SUB_ASPD to Enable
Set UAVCAN_SUB_DPRES to Enable
Reboot
Multiple Airspeed Sensors
If you have multiple airspeed sensors, then you can select which sensor is preferred as the primary source using ASPD_PRIMARY. Value 1, 2 and 3 reflect the order of started airspeed sensor:
0: Synthetic airspeed estimation (groundspeed minus windspeed)
1: First airspeed sensor started (default)
2: Second airspeed sensor started
3: Third airspeed sensor started
The airspeed selector validates the selected sensor first and only falls back to other sensors if the selected sensor fails the airspeed checks (ASPD_DO_CHECKS is used to configure the checks).
The selected sensor is then used to supply data to the estimator (EKF2) and the controllers.
Performing the Calibration
Select "Q" icon > Vehicle Setup > Sensors (sidebar) to open Sensor Setup.
Click the Airspeed sensor button.
Shield the sensor from the wind (i.e. cup it with your hand). Take caution not to block any of its holes.
Click OK to start the calibration.
Once asked, blow into the tip of the pitot tube to signal the end of calibration.
Tip
Blowing into the tube is also a basic way to check that the dynamic and static ports are installed correctly. If they are swapped, then the sensor will read a large negative differential pressure when you blow into the tube, and the calibration will abort with an error.
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