Building a little photographic darkroom in my bathroom, and the enlarger I got came with a giant & heavy transformer as a power supply, and no timer.
Since the 70s, power supplies have become much smaller & lighter, so I got a switching power supply, and I’m controlling the output of the power supply with an Arduino and a solid state relay.
The box is built out of lasercut plywood, stacked and glued together to create that nice stripey effect when viewed from the sides. And I managed to come up with a clever solution to still have one flat side for sockets.
Photos/video at the link below: