Autonomous Bot

Have you ever seen one of those vacuum cleaner robots that move around the house on their own and do their cleaning? Well I have and they really didn't capture my attention until I realized I could make something similar to it with a different take on it. I came up with the idea of taking an IR emitter and an IR detector and angling them towards each other but not directly at each other. So whenever the vehicle came up to an obstacle the light from the emitter would deflect off the boundary and hit the detector and the motor would stop. Essentially the circuit made the motor run continually until the bot came upon an object.

I setup the IR emitter to emit a beam of light at a frequency of 38 Khz. I set the frequency using a 555 timer which is a clock that controls how many electric pulses get emitted per second. Once I had my emitter setup I could now start playing with my IR detector portion. To setup the IR detector I first had to get a detector that did what I wanted it to do when 38 KHz was pulsed at it. I found a good detector that allowed a voltage to leak through whenever a 38KHz light was hitting it. Then I had to pop the voltage even higher for it to work in a logic gate that is called an inverter. I amplified the voltage using a comparator circuit. Once the voltage was high enough I inverted it so the motor would get 0 current and 0 voltage. Basically the motor would run continuously until the IR detector received a 38KHz beam. Once I had it setup it was time to implement it and the next post will show you how I set it up on my prototyping breadboard.