Driving a Simple Character LCD

Summary

Character LCDs seem less of a craze and more of an old technology these days, although I’ve still got a soft spot for them (much like I do for valves and tubes). I can recall when everyone that was modding PCs wanted a small 18-by-2 character LCD modded into their case. I remember the details quite well: more often than not I was the one doing the wiring jobs for them. There were many nights spent cutting up parallel port cables and wiring them into the little LCDs. Then everyone watched in joy as I would write some simple characters to prove that the LCDs did in fact work. After all there was something “high-tech” about being able to display your CPU temperature or your current playing song or even something as simple as the time on a little LCD screen. You can see in Figure 4-1 a simple character LCD displaying the time. These LCDs are everywhere these days. You will find them in printers, vending machines and payphones, or, in my case, by the cabinetful in local electronics markets, of every shape and size. You may even be able to recycle one from a dead device you have lying around. It should be quite simple to desolder the LCD out of the broken device.