What To Do With Old LCD Screens: Hack Your Own Electrochromatic Glass

There's something decidedly science fiction-like about electrochromatic glass. A wave of a hand or a voice command and the window goes dark (or goes transparent). You can get glass like this today or you can add (pricey) film to existing glass, if you prefer.

[Artem Litvinovich] thought about using LCDs as window panes twenty years ago, but the cost was, of course, prohibitive. He recently realized that he had easy access to LCDs out of broken laptops and decided to see if it would be useful as a small window.

After tearing down the screen (and there are a lot of pictures of the tear down), [Artem] needed to find the bias voltage pin on the LCD connector. He grounded a 12V battery pack and put a 10K resistor on the positive lead. Then he touched the pins until he got a slight change in the panel's opacity.

Once he identified the right pin, he removed the other conductors to prevent current draw from the remaining circuitry. It also prevents the onboard drivers from trying to control the panel and interfering with the externally-applied bias voltage.

The electronic curtains don't draw much power, but they also don't go completely transparent (you can see a demo on the video below). Still, an interesting hack and one maybe someone can improve upon. This looks like a fairly simple hack compared to, say, driving an LCD with an FPGA. Certainly, finding the bias line is easier than reverse engineering the entire display.