Ever since I saw the first review of one the matrix orbital LCDs I have always wanted one. The prices were outrageous! $100 for a LCD? Come on! But being the true GideonTech staffer I am (aka cheap) I did a little research and found you can buy and wire up your own LCD for ~$20-30.
What you need:
A male db 25 connector (parallel port connector) (~$1-2)
1 10k Ohm Potentiometer (get a “trimmer” pot) (~$1)
1 100 Ohm Potentiometer (get a “trimmer” pot) (~$1)
Wire (~$1-3) You could also use an old printer cable.
Molex connector (~$1-2)
Project box (optional)
Soldering skills (Pricless)
- A LCD with a HD44780 controller chip or equivalent (~$5-20)
The LCD I decided to go with was a Seiko L2014 4X20 LED Backlight LCD - with HD44780 Controller Chip. I chose this LCD because the characters are green instead of black, and I just liked the way it looks.
Now before we begin I need to tell you that if you plan on putting this LCD in 1 of your drive bays, your out of luck, the metal frame of the LCD itself is as big as one of the 5 ¼” bay covers. So you will need to have 2 slots free to be able to fit this LCD.
EIO also gave out this nice schematic for wiring the LCD to the male db 25 connector. It also seems that this schematic is the standard that everyone that is building software to interface with the LCD’s is using.
Click to enlarge
If you have no clue what this means you may need to get some help in soldering the potentiometers. The 10k potentiometer is to adjust the backlight brightness, and the 100 Ohm potentiometer is to adjust contrast. My old roommate who wired this up for me (ok, I admit it I have no skillz :-/ ) said that the way they have the 100 ohm potentiometer wired doesn’t make any sense to him, but he wired it up according to the schematic and it worked just fine. Don’t let anyone tell you its wrong. One little note if you decide to get the same lcd as me, there are only 14 pins on the board, and the schematic shows 16, the other two pins are labeled a and c and are located on the right side of the lcd, a = 15, c = 16.
A little hint, think about where your wires are going so you can make it look nice, else you will probably end up with sort of ghetto rig looking like contraption.When it is all wired up, and you plug it into the power supply and the parallel port, the LCD will display its initialization screen. This will show the first and third lines full of blocks, it will stay this way until it gets some sort of input from a program. Don’t worry this is a good sign. :-P
Now that we have the hardware lets take a look at the software.
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