A few years back when I was in engineering school, I was shown how to make PCBs using the photo-resist + etch method. As all electronics engineers should know, it's simple enough to do, provided you have the right equipment. The student-accessible gear was fine, until my projects started needing double sided boards with the kind of fine pitch SMD and tiny vias our antique (and single sided) light box couldn't resolve without pesky fringing and alignment issues.

As part of my final year project, I opted to make a new exposure box to eliminate the risky PCB-and-transparency-sandwich-flip and achieve a sharp enough image for 0.15mm features, and to be educational environment proof.

The basic rundown: a glass cartridge suspended between two 10W ultraviolet point sources (LEDs), an ATX power supply (recycling!), custom built constant current driver, and a home-brew PLC/HMI to handle the programmable exposure cycle, safety mechanisms, and communication to future PCB making devices.