If you want to make your own custom PCBs at home, one method is to paint a circuit board blank with photosensitive material, then expose the portion you don’t want to UV light using a printed transparency. After a process of etching and stripping, the correct traces are generated.

As seen here, in order to help with the UV process, GiorgiQ decided to create his own two-sided exposure box. It uses arrays of LEDs to produce the correct light, and an Arduino Nano for control.

The box itself is constructed out of MDF, white acrylic, and drawer slides to allow for easy insertion and extraction of the PCBs. It looks like an excellent tool, and his instructions would be a great place to start if you want to build your own!