> From: Jerry English > Subject: digital watch lcds > > Does anybody know of a distributor or where I can get a small number > of liquid crystal displays of the size and type that are used in > digital watches? I am about at the point of just buying a cheap watch > and using the stuff inside. Funny you asked right now. Yesterday, I reverse-engineered a cheap chinese-made LCD watch. The interesting thing with this one is that it uses a multiplexed LCD, 1/2-duty cycle, 1/2-bias, and so can be driven with only 13 pins, 3 V. This is exactly the number of free I/O-pins on the 18-pin PICs... "Wait," you might say, "multiplexing means you need analog outputs, doesn't it?" Yes, BUT in the special case of 1/2-duty cycle, all segment pins (every segment pin drives two segments) are still digital, and only the two common outputs use an intermediate level. This can easily be arranged by HiZ-ing the common drives and biasing with pairs of resistors. Most seven-segment type cheap LCD-displays that can be bought off-the-shelf are non-multiplexed and require something like 20+ drive pins, which makes it more cost-effective to buy a module instead. I believe most LCD displays are custom made, and become very expensive in small quantities. If you need only a few, I would agree the best way may be to disassemble a couple of watches/timers/thermometers etc. from a local cheap-import store. The watch I got at a local store here seems to be similar to Maplin's YU05F @ GBP 8.50 (1995 catalogue), but I think Maplin is overpricing that one (it is much cheaper here). Good luck, Martin Nilsson http://www.sics.se/~mn/ Swedish Institute of Computer Science E-mail: mn@sics.se Box 1263, S-164 28 Kista Fax: +46-8-751-7230 Sweden Tel: +46-8-752-1574