A simple design for a custom line sensing array, using the well-known QRE1113GR reflective sensor, which is seen in most line followers (including crazy fast PID ones). The same design is also seen in the QTR series from Pololu. Full tutorial is documented on my YouTube channel: https://www.youtube.com/watch?v=jIgIj2hZbxc Notes: You really only need the QRE1113GR itself, and two resistors, however, I decided to add two decoupling capacitors for more stable signals. That makes the entire project just 18 parts, which is pretty simple. Also, the tutorial PCB layout isn't the exact same as the one that I actually printed and used, for recording purposes. (It still works the exact same) Nevertheless, the design files of the one I actually sent off to be manufactured are in this repository.