ThunderFly TFASPDIMU01 is SPI/I2C sensor board equipped with a differential pressure sensor (Senserion SDP3x) and 9-axis motion tracking sensor (ICM-20948). Board is equipped with 7pin JST-GH connector. The sensor board is designed for multiple uses. It can be used as a self-adjusting anemometer WINDGAUGE03 or as an airspeed sensor for UAVs with optional function as the external magnetometer.

TFASPDIMU is commercially available from ThunderFly s.r.o., write an email to [email protected] or shop at Tindie store.

• Type: Differential and 9-axis motion sensor board
• Mass: 3 g
• Size: 36 x 14 mm
• Power: +5 V
• Connection: 7pin JST-GH connector, custom pinout

SDP3x

• Range: +/- 125/500 Pa (depending on exact sensor type)
• Excellent accuracy and repeatability, even below one Pascal
• No zero-point offset, no temperature drift
• Calibrated and temperature compensated
• Fast sampling time of 2kHz at 16 bit resolution
• I2C address: 0x21 (d33)

ICM-20948

• 3-axis gyroscope, 3-axis accelerometer, 3-axis compass (magnetometer)
• Onboard Digital Motion Processor (DMP)
• On-Chip 16-bit ADCs and Programmable Filters
• 7 MHz SPI or 400 kHz Fast Mode I²C
• Digital temperature sensor
• Default I2C address: 0x68 (0d104), can be changed to 0x69 (0d105) by moving the resistor R2->R1.

Ground control station anemometer WINDGAUGE03

Our TFSLOT senzor is an airspeed sensor for use mainly on UAV. Due to 3D printed case it is possible to optimalize part according to the location of sensor on UAV and tune their characteristics. First use of this sensor was on our autogyro TF-G2.

More details about this solution is available in the repository TFSLOT01.

Symmetric variant of TFSLOT sensor for different mounting options TFPIPE01.

This anemometer should also based on venturi effect. Thanks to an clever design, it will measure the wind speed from all directions (without knowing the direction).

In case of mounting on rotation slip-ring bearing the sensor could sense air AoA of the vehicle. Due to ability to turn in direction of airflow. The turnig direction could be sensed differentialy to position of aircraft by IMU embedded in the TFASPDIMU01 sensor.

Full schema is avialible in PDF

** IMG - technical draft **

Due to the possible wider use of the sensor, a standard pixhawk pinout is not used.

To increase the transmission quality, it is recommended to create pairs SDA,GND and SCL,+5V on the cable (as shown in image)

Pixhawk pinout is listed according to the Pixhawk connector standard.

For reading data from the sensor, we have prepared a python script in PyMLAB library that uses the pySMBus to readout data. It can be used directly from a computer with a corresponding converter (for example MLAB USBI2C01A) or with one-board computers (Odroid, raspberry and similar) that have own smbus output.

Calibration can be verified by mounting of an anemometer to car roof and comparing it to speed obtained from GPS (gpsd). This needs to be done in windless weather.

We are now working on implementation of driver into PX4 stack.

Main usage of this sensor is as airspeed sensor. It can be also used as an external magnetometer and thermometer.

We are currently unable to implement the sensor in the Ardupilot flight stack. However, we will be happy to provide assistance with implementation. You can contact us

TODO