147. Diagram 22 shows the Electronic Compass. This component is required so that the vehicles obstacle avoidance function can be implemented as described in this text.
148. It provides the reference that the Distance Controller uses to define direction, because it always points to magnetic north.
149. When a vehicle comes off the production line it will be pointing towards magnetic north which will be exactly in line with the Electronic Compass. At any time within the life span of a vehicle, it will be pointing in a direction that is relative to magnetic north and it will, therefore know it's own direction.
150. The main components of the Electronic Compass:
A. Two light emitting diodes (LEDs) are fixed to the ends of the compass needle. Each one has a different color.
B. There are 40 light receiving transistors (LRT) placed around the edge of the magnetic compass needle so that they are vertically opposite to the LEDs. For this implementation, the angular distance between each LRT is 9 degrees. The number of (LRTs) around the edge of the compass can be increased in order to increase the angular precision of the measurement.
C. The Component Controller in the compass collects the position of the two light receiving transistors (LRTs) that are turned on when light reach their surfaces. It then calculates the direction in which the vehicle is pointing relative to the earth's magnetic field and then sends that information to the Board Computer that then sends that information on to the Main Signal Processor. The Board Computer also transmits the same information by radio link to other vehicles in the vicinity, so that they will also have that information.
Electronic Compass measures the direction of an electric vehicle