LightBot v1

For the disabled, and for those who have their hands full, a hands-free light source can be desirable. The goal of this project was to create a simple robotic flashlight that would follow its user around, rather than be carried.

Step 1 Materials

This robot follows an infrared beacon clipped to one of the user's shoes. The infrared light is generated by four infrared LEDs harvested from old TV remotes. The robot sits on two wheels from a K'nex set and moves using two small hobby motors controlled by the input from two infrared phototransistors to the bases of two NPN transistors. I wanted to use photoresistors rather than phototransistors, but I found that these have a very wide angle of sensitivity and are not exclusively sensitive to infrared light. They also contain the toxic metal cadmium, and proved difficult to find in shops. Phototransistors are similar in shape and size to standard LEDs, and infrared phototransistors are widely available. Resistors were needed to bias the transistor. The robot is activated by two switches, and powered by 3 AAs and 1 9V battery. Everything is housed in some PVC tubing, and rubber bands hold everything together. The k'nex wheels are attached to the motors with hot glue. A disposable plastic fork was stuck on to provide support. This truly is version 1, and I am working to improve this system.

Comments

[scraptopower]

Be nice to see a video of this. Is there any reason you couldn't connect the resistor from the 4.5V batter to the 9V battery instead. It'd save carrying an extra battery.

[elephant1292]

Normally this would be possible, but I've no information about most of the components. The next version will probably be able to run on a single power source, but it was simpler to use two for this.