Homing Beacon

The homing beacon is placed at the point that the robot needs to return after completing the vacuum task.  It works as a transponder.  The robot vacuum cleaner sends out infrared pulses which the beacon sees and responds to.  The beacons response pulse  is delayed 3.5 milliseconds.   The robot has two infrared sensors on the top of its body.  One has a view to the right and the other the left.  If the right sensor sees the return signal the robot steers right.  The left sensor causes the robot to steer left.  If both sensors see the beacon it steers straight ahead.  Once the robot has reached the beacon it must stop.  This is done with a forward looking reflective infrared sensor  on the robot.  When this sensor "sees" an object the robot is programmed to stop. Since the beacon is placed against a white wall the robot will stop when it gets within about 8 inches of the wall/beacon.

 
 

 
beacon dissambled