A very simple light-following robot can be made with just a few light-dependent resistors (LDRs), batteries, and a motor. The trick here is that the LDRs on one side of the bot allow current to flow to the motor on the opposite side, thus effectively turning toward the light when not a direct path, and moving straight when the bot has locked onto the light source.
It’s a fun science project for those that want to get started in electronics, but actually linking the motors electrically and providing a mechanical structure can be cumbersome. For this purpose, and as an experiment in creative PCB design, I came up with this Light Follower Robot PCB. The PCB not only looks like an 80s video game spaceship, but passes electricity to the appropriate motors from a bank of 2 CR2032 batteries. A soldered-on paperclip acts as the tail to allow it to pivot, and a pair of 3D-printed wheels move it forward.
You can see it in action in the video below, along with the design process. Documentation, which includes KiCAD files, along with the other non-PCB parts needed to complete the ‘bot are found on GitHub.
