One of the next stages of robot navigation was to have the bot be able to move about freely without having to worry about it bumping into objects or getting stuck against the wall. The first step to this was to install "whiskers" on the bot that would sense when the bot brushed up against something and then cause it to stop and change it's course. The "whiskers" were attached to a simple switch that was normally open and when closed would tell the bot to back up and go on a different course. Special attention had to be paid to corners so that the bot wouldn't get stuck by continuing to execute the same move that would just continue to keep it going from wall to wall.
While this worked well the bot would still have to come in contact with the object to be able to sense it and change it's course. The solution to these was to install Infrared (IR) emitters and receivers on the front and use the reflection from them to sense an object in it's path. Care had to be taken to watch out for IR interferences from electronic devices. It's interesting to note that any simple TV, DVD, Stereo remote would easily confuse the bot into thinking something is in it's path. Otherwise as you can see the bot will continue to roam and avoid objects successfully.