As far as I know, QLOCKTWO® was the first company to sell word clocks. These beautiful objects have only one issue: they cost you an arm and a kidney. The concept behind the scene is simple: they display time as text. For example, instead of displaying 09:55, show it is five minutes to ten. For a while, I wanted to build one for myself, and had the software part down quickly, but had issues with the hardware. In particular because of the light leaks.
Light leaks? Yeah. To understand the problem, you need to know how these devices work. A matrix of letters encodes words we use to write time. With my previous example, the terms it, is, five, minutes, to, and ten need to appear in the matrix. All the other letters are DC – Don’t care. The more random, the better it is. Behind the faceplate, with the letters punched-out of the material, there is a light diffuser material and LEDs. These LEDs are ideally sitting in light wheels, and are switched on and off as needed by a microcontroller. As always, the hard part is the execution.
Where QLOCKTWO charges thousands of dollars for an impeccable implementation, my cheapo version was flawed, and the light was leaking – or bleeding – all around the place, rendering the clock, meh at best. A few years ago, when Sharper Image (SI) sold a small instantiation of the concept for twenty bucks, I bought one even though it came with a copper finish – which is not to my liking. It ended buried in a box.
Today, my wife was working on one of her projects that required spray painting. Aha! I decided to unearth the clock and to replace the copper finish with some of the back pain she was using. Luckily, and surprisingly, it is possible to disassemble the SI word clock. Only issue: the center of the faceplate is glued to the plastic frame. I tried to detach without destroying too much of the light diffuser film.
After a quick sanding, the copper-finished was gone for good, and the surface ready to receive a coat of black paint. Tada! A few observations: the PCB is clean, and the position of the words is marked by the silkscreen, which will come handy if I decide to re-use the circuit in another project. On the low side, the surface-mounted microcontroller package is unmarked, so it is hard to say much about it. Overall, I am happy with the result.
