LCDPresentation View Online

Build an LCD Display for your Computer

(page under construction)

A recent project for our [K-LUG] Linux User group was to create ourselves LCD Displays for computers. We created kits containing all necessary parts for < $20. Some used their LCD Display to show the health of their headless servers, some to show off title and artist information from an MP3 player, and others still to simply have fun with animation. Here is a picture of one of the finished products

http://www.pcig.info/uploads/Main/LCDTuxsm.jpg

Intro to the LCD Kit Project

Welcome to the first K-LUG project involving the attaching of interesting hardware to a computer. We created this project because one member had several monitorless servers he wanted to view performance stats on. We also picked this project so we would have some interesting code to write, and we figured it would be cheap, easy and fun! Ideally our attached display would connect via USB, however, we chose a parallel port connected display because no one seems to use the parallel port anymore, and by using a parallel port the kit was easier to code and cheaper to buy.

LCD Kit Parts list

__ 10K trim pot __ 25 pin male D IDC __ 3 pin single row header __ 3 pin socket shell __ 2 female socket pins __ 16 pin header __ 26 pin header __ 26 position dual row socket __ 27 ohm 1/4w resistor 30584CC __ 26 conductor ribbon cable 6” - 24” __ 2 line x 12 character LCD __ Interface Circuit board

Kit Options

The kit contains a 3 pin single row header, a 3 pin socket shell, and 2 female socket pins for the power connection. Both of the outer pins are ground, the center pin is +5 volts. Only one ground pin requires a connection so only 2 socket pins are supplied. If you would prefer to hard wire the power connection these parts can be ignored and the power connections soldered directly to the board. There is enough ribbon cable for a 24” length between the 26 pin header and the 25 pin D connector. If you plan to mount the display in a box, with the 25 pin D connector mounted on the box you may want a shorter cable rather than try to stuff 24” of cable in the box. Consider what you want and we can cut the cable to fit.

Background Information

When you first look at attaching an LCD display to the parallel port, it looks simple – a bunch of connections, a potentiometer, and maybe a resistor for the back light. In fact, it can be messy and discouraging. This kit is designed to make the interface simple. It was designed by Dennis DeLorme and [Kevin Neff] – if you have questions they should be able to help.

When attaching an LCD display, there are several options for the control functions. Rather than invent our own, we used an existing definition originally used by a Winamp add-on. The connections are as follows.... will convert more later...

LCD Connections table

Parallel Port	Port Function	LCD	LCD Function
18-25	GND	1	GND
--		2	+5V
--		3	contrast
16	initialize	4	RS
14	-linefeed	5	R/-W
1	-strobe	6	E
2	Data 0	7	DB 0
3	Data 1	8	DB 1
4	Data 2	9	DB 2
5	Data 3	10	DB 3
6	Data 4	11	DB 4
7	Data 5	12	DB 5
8	Data 6	13	DB 6
9	Data 7	14	DB 7
--		(15)	(back light +)
--		(16)	(back light -)

Note: Pins 15 and 16 on the LCD are not standard so may not be on every LCD. Even if an LCD has back light capability, the connections may not be on the connector