This avoids the problems that can occur because of uneven surfaces in an emitter-detector arrangement. If only one beam senses a table, the robot can be re-aligned until both sense it. Of course, a fixed field IR gives no sense of distance. Vertical break beams running between the upper and lower level of the robot determine this. Again, if the left break beam fires and the right does not, the robot can be re-aligned.
Vision is a critical element in manipulation.
Spare your sacroiliac with the new direct drive joystick kit. This joystick plugs directly into a PeopleBot or P2 microcontroller so that you can drive your robot to demonstration areas without a computer connection. With the introduction of the tall PeopleBot, we've been motivated to upgrade our robots' sonar capacity to 24 instead of 16. Or set up a game of botball in your lab. You can run four robots in the same space, each controlled by a user in a different place.