Jan 182022

People leave useful things out on the curb all the time. Toaster ovens. Kid’s shoes. Sofas. Old TVs. Not-so-old TVs. And, often, printers. Inkjet printers, in particular, are a rich source of important nutrients such as motors, gears, sensors, wifi, and power supplies. It’s always fun to pop them open and salvage the good stuff.

A motor driving a shaft with a quadrature encoding wheel attached.

These are parts from an Epson WF-2540 I found in the trash that I spent a morning disassembling with my kids. Look at this beautiful quadrature encoder wheel. And that lovely little stepper and worm gear! There’s even a peristaltic pump in this one. It’s a bonanza. Every time I disassemble a printer, I end up with three piles: one of useful parts, one of plastic and metal scrap for recycling, and one of components that are too specific to make use of. Oh, and one of these frickin’ things:

control panel of an Epson printer, with many buttons and a color LCD screen

Oh. You again.

My old nemesis, the control panel. A couple dozen buttons, a few LEDs, and a color LCD, all in a well-designed, sturdy package. I can think of a half-dozen uses in a heartbeat. Wouldn’t it be nice to use this as an interface for a media player? A robot arm? A pen plotter? Your air conditioner? A midi sequencer? An overly complex toaster?

The problem is that every control panel is its own reverse engineering project. Usually I just give up on these as being too complex to reuse as a single unit, but for some reason I thought this time, I’d give it a whirl. After all, that flat cable coming out the back only has fourteen pins. How hard can it be?

I approached this project in two stages. The first was to be able to read all the keypresses and blink the LEDs, which I was pretty confident I could handle. The second, being able to display images on the embedded LCD, was, well, trickier. But let’s see how far we can get!

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 Posted by at 8:37 pm