NMEA compass with IMU. The device will transmit NMEA-0183 sentences for magnetic heading, roll, pitch, rate of turn. It can be used directly with OpenCPN running on Windows or Linux.
Transmission of NMEA-0183 is via USB Serial at 115200 baud, with 10 Hz rate for NMEA sentences.
- M5Stack AtomS3R esp32: https://docs.m5stack.com/en/core/AtomS3R
- M5stack ATOMIC PortABC Extension Base: https://shop.m5stack.com/products/atomic-portabc-extension-base
- Waterproof IP67 box 4.7"x3.5"x2.7" or bigger. Hinged with transparent lid, base plate and legs
- Various cable glands
- M3 standoffs
- USB-C to USB-A cables with small support tang on USB-C end
atomS3R_compass.ino in atomS3R is an ArduinoIDE sketch which you would need to compile and load to atomS3R.
For required libraries and their versions check: .github/workflows/build.yaml
Calibration is performed directly on AtomS3R in three steps (follow instructions on the screen):
- Accelerometer. On AtomS3R screen is a button (BntA). You will need to place device in 6 poses (still).
- Gyroscope calibration is performed by putting device still with screen up.
- Magnetometer calibration achieved by rotating device around all axes for around 45 seconds.
- Triple press on the screen erases and restarts calibration.
NOTE: You would need a relatively long USB cable to be able to rotate the device fast and freely to give more points on 3D sphere.
$IIXDR,A,-0.4,D,PTCH*43
$IIXDR,A,2.3,D,ROLL*79
$IIROT,1.9,A*2E
$IIHDM,250.4,M*21