by Web FishJan 6, 2013 @ 02:03pm
Provides information about about momentary vessel orientation with respect to the earth's magnetic field (compass), as well as earth's gravitational field (accelerometer). Basic navigation instrument.
- Current selection: LSM303DLHC 3D Compass and Accelerometer
- Status: Finalized
- Criteria: Sensitivity, standard I/O, small physical footprint, cost
- Finalists: Sparkfun HMC6352, Sparkfun LSM303 Breakout Board, Pololu LSM303DLHC 3D Compass and Accelerometer
- Main decision factors: Cost, standard I2C bus interface
(click image for larger view)
Spec highlights:
- Dimensions: 0.5" × 0.8" × 0.1" (13 × 20 × 3 mm)
- Weight without header pins: 0.6 g (0.02 oz)
- Operating voltage: 2.5 to 5.5 V
- Supply current: 10 mA
- Sensitivity range (configurable):
- Accelerometer: ±2, ±4, ±8, or ±16 g
- Magnetometer: ±1.3, ±1.9, ±2.5, ±4.0, ±4.7, ±5.6, or ±8.1 gauss
Caveats:
- Still unclear how well (if at all) the tilt compensation will work in a constant motion (sea waves) environment;
- Unclear whether we'll be able to use built-in accelerometer to determine vessel orientation up/down (current flip status) - again, due to constant acceleration changes from riding surface waves;