PHIL, the Light Tracking Robot

As humans, it’s easy enough to tell where a light source is coming from, but robots — and microcontrollers in general — don’t normally have this ability. 16-year-old South African robotics enthusiast Sean O’Donovan decided to create a robot to sense and track a light source on two axes, for no other reason than it’s a cool project.

The build utilizes four light-dependent resistors with voltage dividers to sense the beam intensity in four quadrants, separated out by a 3D-printed light shade. The resulting voltages are sensed and compared by an Arduino Uno, which adjusts the sensor/shade gimbal assembly to attempt to point towards the offending light. Two micro servos provide rotation, and a pair of 100µF capacitors are employed on the input lines to help prevent voltage drops to these motors.

Code and print files are found in O'Donovan's write-up, and a demo and quick summary of the build process are found in the video above. Although the project was simply put together because it was cool, one could certainly see this sort of concept used to track the sun for solar panels, or any number of other purposes. Besides, you never know what new ideas a "just because" project will open up!