1. Compass module

2. Possible new version Readout I2C 6 axis Accuracy 1-2 degrees
3 magnetic
3 accelerometer
Accuracy 1-2 degrees
PMT size 72 mm at 212 mm is 330 mrad
Accuracy of compass 1/10  33 mrad = 1.9 degrees

3. Many chips available
Robotics and mobile telephone have made chips cheap and low power in the past years
Chips are readily available most have gyroscope also. Some easily available models are
MPU-925x (includes a secondary I2C bus and DMP)
LSM9DS1 (9d) , LSM303D (6d) simple readout via I2C of axis values
Power consumption:
Magnetic sensor setting ODR = 6.25 Hz, accelerometer sensor ODR = 50 Hz and magnetic high-resolution setting: V = 1mW.

4. STMicroelectronics

5. Tests Test done with the LSM9DS1 on breakout board from Sparkfun.
Calibration: measurement in six orientations of acceleration and magnetic field to determine zero offsets.

6. Tests Installed on CLB Read out through I2C bus
Stable within 0.5 degrees
Operates in any orientation
Z-axis accelerometer offset by 0.5 g
Absolute pointing (comparison to normal magnetic compass equal within measurement accuracy)

7. Setup

8. Pin compatible PCB A PCB has been designed for the LSM303D
Requires Footprint of LSM303D and 2 capacitors and 2 pull up resistors
Axes are equal to AHRS
Will be delivered most likely on Friday Feb 5 (€2500 for 100 items, speed delivery).
Will be tested and calibrated “off-line”
If all OK build it into a DOM and fully test it.

9. Conclusions
Next week we will (probably) have a pin compatible compass board.
Cost around €25 (full production ~ € 10)
Power consumption 1 mW.
For future could place it directly on the CLB