Heat-based laminators, an office staple, are often pressed into service by electronics hobbyists looking to produce printed circuit boards using the toner transfer method. Nick Poole, though, has been using his office laminator for a different purpose: creating self-contained, waterproof circuits on the cheap.
Described in full over on the SparkFun blog, Nick's experiments have been taking place over the past few months and are surprisingly detailed. Starting with a membrane-based potentiometer, Nick was able to create a laminated four-key touchpad; emboldened by success, Nick turned to a larger alphanumeric keypad for another project. So far, his experiments had concentrated on unpowered and already-paper-like components - but Nick wasn't finished.
Putting a battery through a heated laminator is perhaps not the wisest of moves, but taking various precautions - including "imagining what it would be like to clean the burst coin cell out of the disassembled laminator" - Nick threw a simple battery-and-LED circuit through the device. To his surprise, what came out of the other end was a sealed and still-functional torch - but one which is now entirely waterproof thanks to the lamination.
Skipping to the end, Nick's final creation is undeniably impressive: a keyboard based on SoftPot membrane poteniometers, small buttons, LEDs, a piezo element, and an Arduino Pro Mini, all sealed in the polyester pouch with only a small hole for the Pro Mini's FTDI breakout connector. Providing your projects don't involve sharp components sticking up out of the board, then, it appears that Nick's trick is a clever way to quickly package up loose parts into a portable and neat whole - and the transparency adds a great look to boot.
So, what’s next for laminated circuits? Well, I’m cooking up a scheme to construct a binder with power and ground rails to power a whole stack of these circuits, which you can flip through like a book. If this project ever comes to fruition, I’ll write about it in an upcoming blog post. Also, I’d like to experiment with different ways of providing power to projects that are sealed in laminator pouches, such as inductively charging thin lithium cells, or inductively powering the circuit directly.