DIY Tools for Home PCB Etching

Today, getting custom PCBs is easier than ever thanks to a variety of suppliers that will follow your specs for generally very reasonable rates. On the other hand, once you put in your order, you’ll be waiting for days or even weeks for your awesome new design to arrive. There are a few alternatives, including using a photoresist method to selectively expose special presensitized PCBs. You can then develop them with sodium hydroxide solution and “wash” the excess off with an etchant solution like ferric chloride.

It’s a lot more work than simply shelling out a bit of cash, but you can have the PCB today. To make this process a bit easier, and more consistent, TechBuilder has come up with two helpful devices. The first is an Arduino Nano-based PCB exposure box, which mounts an array of LEDs on the lid of a plastic box. These LEDs shine down to expose the PCB under a carefully printed piece of paper, for a set amount of time that is adjusted with a potentiometer. Control is handled by a TIP31C transistor and light levels can be adjusted with a second potentiometer. When it’s done, the lights turn off automatically, and it signals you with a small speaker.

To keep you from having to manually agitate your PCB while etching, he’s also come up with an automatic shaker. It moves with a DC motor and a linkage setup to push the fluid container up and down, and features speed control via a DC-DC converter and a potentiometer for user interface.

For an intro to PCB etching in general, he goes over the process in the third clip below, with rather clean results.