Remember the LCD panel I salvaged a few weeks ago?
Well, I finally put it to use. As it happens, I am setting up a small multipurpose server for my home. The motherboard I’ll be using happens to have NTSC out, and this LCD happens to have NTSC in. So not only could I use this LCD as a mini-monitor, I could also dress it up and use it as a digital picture frame. So that is what I did:
I would say that the most difficult part of this project was figuring out where to get weird voltages such as +8v and -5v. The +8v source was relatively simple. Since the inverter powering the backlight required a +12v supply, feeding this also to an LM7808 regulator yielded the +8v. Since the PC power supply I use for testing does supply -5v, I actually considered tapping off the power supply in the server until I discovered that the server’s power supply omits the -5v line. But I soon discovered this circuit , which uses a 555 timer and a few diodes and capacitors to produce a negative voltage, which not only worked, but also allowed me to power the entire project with a common 12v wall wart.
I also found this handy Capacitor Value Calculator , which translates the arcane three-digit codes on ceramic capacitors into the actual capacitance value.