# Attach a cool hitachi 44780 LCD! Tutorial



## gotrootdude (Feb 19, 2003)

This is the beginning of my tutorial for attaching a LCD onto your parallel port for displaying information such as what's playing in winamp, cpu usage, etc..

I will attempt multiple ways of attaching the LCDs with my experiences with getting them to work with each software program, and give a final review of my findings..

I will start using the Jalcds wiring schematic for software controlled backlighting and contrast found here:http://www.jalcds.de/

The LCD's can be found on ebay for around $10 after shipping cost.. Not all are the same, some have 16pins across the top or bottom, some have pin holes aligned 2x8 across on side.. Non-backlit units have 14 pins.. Some backlit units have two solder spots labeled A & K for powering the backlight.. Also, some use pin 15 for power, some use pin 16, so if you can check the datasheet for it first.. I repeat: normally pin 15 and 16 are reversed, but not always!

Experience needed: Advanced
Time required: Some say 30 minutes, but I'll say you'll need a free day
You'll also need a bit of soldering skill.. Mine isn't great, but I've done worse..

Parts required for the Jalcds method:

1 44780 compatable LCD (I recommend using a LED backlit LCD) (The EL backlit LCD's may work, but some require a separate invertor and I won't cover how to hook it up here.)
1 100ohm potentiometer
1 10ohm potentiometer
1 1N4148 Diode
1 150ohm resistor 1/8watt
1 BD135 transistor
Soldering iron
solder
25 pin D-sub or old parallel cable (I recommend the D-sub, I found the wires in parallel cables not to be standard, small, and difficult to work with.)
*Warning*: If you use a old parallel cable, check the wires to make sure that the cable has a wire going to each pin, and that there's only one wire for each pin before starting to solder! I ruined on LCD by finding out that the cable didn't have all the wires before starting, and removing the solder..

A good spool of wire
A male molex connector
Something to insulate your connections

optional:
multimeter if using a old parallel cable
A good spool of wire, solid core is easier to solder and work with.
A external molex pass through. 
I used liquid electrical tape from walmart for insulating the connections.
split loom, wire wrap, heat shrink, etc.

The transistor, diodes, resistors,etc can be found at a reasonable price and reasonable shipping at www.electronics123.com
Wire can be found at your local radio shack.

I will post pictures as they come available. (be aware, I'm not going for neatness until later.)


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## gotrootdude (Feb 19, 2003)

I found that it can be confusing as to which wire goes where, so I recommend starting with soldering the 1N4148 Diode to the 150ohm resistor first (the darker end of the diode goes away from the resistor), then solder the other end of the resistor to the center of the BD135 transistor.. The leads on the transistor can be snipped a bit..

Next solder the emitter on the BD135 to one side of the 10ohm potentiometer and the collector of the BD135 to the 100ohm potentiometer.. As pictured here:
http://www.jalcds.de/images/4x20backlight.gif

The datasheet shows how to tell what's the emitter and the collector of the BD135: http://www.ortodoxism.ro/datasheets/philips/BD139-16.pdf

One you get this done, it's time for the next section.


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## gotrootdude (Feb 19, 2003)

You have a choice here, either cut parallel cable for the length you want, or use a D-sub.. I used a parallel cable, but quickly found that the wires were to bothersome to try to attach directly to the LCD, so I cut the cable close to the pin connector, then stripped the wires, then used a multimeter set to read resistance to figure which wire went to each pin, then soldered on solid core wire to the wires I needed and insulated each connection.. (long sentence..)

I cut several lengths of wire to the same long length for the distance away from the PC I wanted the LCD to be. Then I started with pin 1 on the LCD traced the schematic and soldered it with a long precut wire to the same side of the 10ohm potentiometer that the BD135 was soldered. Then I worked my way down the schematic.. Pin 2 on the LCD to the opposite side of the 10ohm potentiometer with a long wire, pin 3 to the middle of the 10ohm pot, etc.. The schematic is here: http://www.jalcds.de/images/4x20backlight.gif

I recommend not wiring the molex connector in for power until last.. You'll have enough wires strung around your workspace that the simpler the better.


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## gotrootdude (Feb 19, 2003)

As you work your way down the schematic, you should notice that you can have your potentiometers on one side of your bench, and your parallel port connector on the other side.. This is intentional so that you can have as many wires out of the way as possible..

When soldering, collect a little solder on the very tip of the iron, then push the wire through the hole, and touch the tip of the iron to the base of the wire and move it slightly around.. Use as little solder as possible to insure a tight connection.. Too much solder can cause a faulty connection, or worse a short across contacts..


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## gotrootdude (Feb 19, 2003)

Well folks, you'll have to wait until tomorrow for pics, I'm done for tonight..


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## gotrootdude (Feb 19, 2003)

I will post pictures soon.. I'm just lazy..

I've also gotten ahold of some Noritake 113's 128x32 graphical vfd's that I plan to incorporate into a few media center, there's a plugin for MediaPortal that drives them..

To get them wired, I used a old floppy cable, I trimmed the connector with a razer blade until only the twenty required pins and wires were left, then I hot glued the connector to make sure it didn't come apart and plugged it in.. Then I wired it to the parallel port with this schematic. http://liquid-mp3.schijf.org/schematics/noritake_gu128x32-311.gif

The things are a little big, and you have to work carefully to keep from dropping and breaking them. I'll post some pics of them working as well..


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