Wingsail Angle Sensor

Wingsail Angle Sensor 

The vessel does not have any explicit wind sensors for measuring wind speed or wind direction.

All sailing navigation decisions rely on knowing the angle of the self-trimming wingsail against the hull.

The wingsail angle is measured using the MPU9250 IMU as a magnetic sensor, and magnetic disk attached to the wingsail.

The MPU9250 may be an overkill for a magnetic sensor, however they do have benefits:

• I2C bus, so it easily interfaces to the Arduino microprocessor.
• Sensitive as a magnetic sensor, allowing good separation distance to the magnetic disk
• The MPU9250 was difficult to use as an actual magnetic compass because it was difficult calibrate and use. They are easy to use as a magnetic angle sensor however. They are not expensive and I have a few to spare.

Wingsail Angle Sensor with Wingsail Magnetic Disk

 The housing for the Wingsail angle sensor is a 3D printed shape that is integrated with the Mast Tube deck plate. 

Magnetic Sensor Housing fixed in place. 

The magnetic disk is attached to the wingsail, so that the magnetic field created by the disk rotates with the sail The disk consists of a 3D printed holder for an array of about 60 cylindrical magnets 2mm diameter, 10mm long. Its obviously important that all of the magnets have the same orientation.

3D model of the Wingsail Magnetic Disk 

Future design changes:

•  Integrate the Magnetic Disk more tightly with the Wingsail, possibly by incorporating it with the bottom foil section.
• Add a duplicate MPU9250 Wingsail angle sensor for redundancy. 

Note: This is part of the ongoing development of a low cost autonomous oceangoing sailing drones, utilising a self-trimming wingsail. This is the Voyager series of sailing drones.