1. Magellan : Compass Sensors
There exist only a few kinds of magnetometers able to read weak magnetic field strength :
Mechanical magnetic compasses OUT
Flux-gate compasses OUT
Hall-effect compasses MAYBE
Magneto elastic compasses DUNNO
Magneto resistive compasses MAYBE
Mobile Robot Development Spring 2002

2. 16-861- Mobile Robot Development Spring 2002
2 Options
Devantech magnetic compass:
- Magneto resistive type
- 0.1º resolution & 2 1D chips
- Own sample code to hack with
Dinsmore digital / analog sensor
- Hall-effect type
- 8 directions of heading information
- Customer sample code to hack with
Mobile Robot Development Spring 2002

3. 16-861- Mobile Robot Development Spring 2002
Dinsmore Sensor
Electromechanical based on Hall effect technology
Digital: Power 1 – 30mW
Analog: Power 18 – 30mW
Analog tolerant to huge external flux field (up to 1,000 Gauss)
Note: Faraday’s Law applies
Mobile Robot Development Spring 2002

4. 16-861- Mobile Robot Development Spring 2002
More on analog
Output resembles sine-cosine curves
8-bit AD converter for digital information
tangent = sine / cosine  comparator for absolute value measurement
Microprocessor AD
sine
cosine
Mobile Robot Development Spring 2002

5. 16-861- Mobile Robot Development Spring 2002
Example: Roboat
Motor
Microprocessor
Sensor
Mobile Robot Development Spring 2002

6. 16-861- Mobile Robot Development Spring 2002
Still a bit more
Local manufacturer based in Girard, Pennsylvania
Possible design assistance from people within
Key people for informal meeting this Thursday afternoon, 22 Oct 2002 (to be confirmed)
Mobile Robot Development Spring 2002

7. Magellan : Ultrasonic Range Sensors
Mobile Robot Development Spring 2002

8. Devantech SRF08 Ultrasonic Ranger
Sensing range of 3cm – 6m
5V, 1.5mA
43mm w X 20mm d X 17mm h
Communication via standard IIC bus
Mobile Robot Development Spring 2002