Introduction

In late 2001 I was doing some research and found out about LCD Screens. These are the small screens like on a calculator or phone, not the expensive LCD monitors you can buy. I found a place that sells these screens quite cheap with resonable shipping to Canada. EIO.com has an excellent selection. I have ordered 2 things from them since then but BEWARE - their "4-7 days" shipping has in reality been 3-5 months!!! I have no idea how they managed to take so long, but when it took 5 months they shipped to the wrong address, recieved it back where they are in California and then shipped it to another wrong address. It was ridiculous trying to talk to them. In any event, I eventually got the product at a good price. Note: they have a minimum $20 order so I got a couple other people to order things as well.

If you are considering building an LCD screen for yourself (fun project) make sure that you get one with an HD44780 controller. Any LCD with this controller can be controlled with the software out there written to control these LCDs. Software to control other chips is harder to find.

I really got interested in these when I saw few other peoples' projects on the net. Wolfy's LCD and Gideon Tech are good examples. There was one project that showed Winamp's spectrum analyzer on the LCD which looked really amazing. I knew I had to build one.

Building the Enclosure

The Completed Unit. Backlight is off. Check the next page to see shots with it on.

The screen arrived 3 months after I ordered it in a nice blue plastic cover, very clean and shiney. I printed off the schematic diagram and got to work.

Picture from GideonTech (No DigiCam at the Time), but my screen is identical.

The HD44780 schematic I used. Note: pins 15 and 16 are on the left of the LCD.

Construction

I cut the large hole in the front with a skills saw. I cut the parallel port connection hole with the skills saw as well. I filed them down to get the correct size. I drilled the holes for the knobs and for the bolts to hold in the LCD. After the screen was in place I ran a quick line of black silicon so that there were no gaps.

Wiring

When I first had it wired up it was just a crazy mess of wires. It actually looked a lot like the keybaord hack in the mame project. It took me several months, but eventually I got it wired up nicely in a project box.

Here's a picture of the guts of my unit. Shrink tube really is the eight wonder of the world. It's so useful. The parallel port connector is on the left and hooked up directly to the connector at the top of the LCD. I bought the connector cable at EIO as well for 99c, makes things much easier.

The solder board in the bottom is glued there so that it doesn't bounce around. Whathat you can't see is that on the other side there are 2 big solder groups. One being +5V and the other being GROUND. The model I ordered is a 4x20 Backlit LCD. That means that it can be lit up so that it can seen in the dark or you can turn the backlight off. The knobs (potentiometers or variable resistors) are for contrast and backlight control. The values in the schematic in my opinion are MUCH higher than they should be. After some testing I found that 2K and 100R variable resistors worked much better than the suggested values.

Here's a picture with the lights off with the LCD's backlight on. Looks really neat in my opinion. The brightness of the backlight is controlled by one of the variable resistors.

When the screen is first powered up you should get a test signal. It looks like darker lines on row one and three. If you wire it all up, power it up and can not get the test signal, chances are you've done something wrong. The test signal goes away as soon as the screen gets some information from the software.

Power

When I was thinking about the way I wanted to build it I knew that I didn't want to have any long cables coming out of it and that I wanted the unit to be able to work anywhere, so I could bring it to school for example. My original plan was to use a 5V external power supply to power the screen. For some reason, when I tried it I had no success. The screen had these wavy lines running down it. So, the only other option was to use the computer's +5V. Although it makes the unit not 100% portable because you need to open up the computer case to feed it power, it's not too bad.


The Cable: I cut the molex power connector off an old case fan, attached it to several feet of speaker wire then cut off the end of an old pair of head phones and used the jack. Intersting Fact: This is the first time I ever used shrink tubing.	The Connection: I didn't realize you could buy female audio connections - so I de-soldered one off of a sound card (which still works). Then installed it into the project case and then had a plug-n-play power connection.

I bought the parallel port connector at KWSurplus and the project box at Sayal electronics. Sayal is another great store right near my house. They cater mostly to university students and hobbiests. Students get a 10% discount

Page 1: Construction and Wiring
Page 2: Software and Screenshots

JBProjects.net

Introduction

Building the Enclosure

Construction

Wiring

Power