Tech Olive

Out of perhaps my hundreds of electrical creations, my favorite would be my 4 row by 20 line LCD driven by a parallel port (seen above). It’s simple yet has functionality; unlike a few other un-mentioned projects. Moving on, in this DIY I’ll attempt to teach the masses on how one can connect his or her own LCD to a computer in order to display information on the cheap and easy. This guide assumes you know how to solder already (it’s nothing SMD or micro so don’t be afraid if you’re not perfect), and other general electronic knowledge.  But enough with the explanation, lets head on to parts!

The combined total of this project should hit around $20 USD, depending on if you already have some of the cables, bits, and bobs already.

The heart of the project is the display. There are hundreds to choose from ranging from 1×4 to 4×40 (rows by lines) from green, to red, to blue! As long as it has an HD44780 controller chip, it will work. I also suggest finding a screen that includes an LED back-light. My recommended resource: Your junk bin. For those without a junk bin: Eio.

Next, you’ll need a printer cable, as long as it has a male DB25 end, it doesn’t matter what is on the other end – it gets cut off anyway. My recommended resource: Thrift stores during half price day = 50 cent cable.

If yours comes with a back-light and you would like to have more settings than just simple ON and OFF and a little contrast adjustment, you’ll need two potentiometers: A 10k ohm for contrast and a 100 ohm for back-light adjustment. Any will do though. I found some large ones that came out of an old speaker system. My recommended resource: About any electronic shop will have these, but there is always the good ol’ junk bin.

The final item that is mandatory is a way of getting power to the LCD. You could use whats called a wall-wart or draw it from USB. For this article, Ill show a neat trick to get a clean connection to the 5v rail on your computers power supply. So you’ll need an old male molex connector. My recommended resource: An old fan adapter.

The final piece of the project you might need to scrounge up is a box to hold and display your LCD. I found a cheap $5 USD picture frame at Wally’s World, but anything goes here!

Finally comes some tools and those ‘bits and bobs’ you need. Also a soldering iron (this includes flux and solder), some electrical tape, extra wire, wire strippers, multimeter, pocket knife, hot glue, a pen (yes, preferable one you don’t mind destroying), a clean work area, and a caffeinated beverage – there is no exception. The final item is imperative and the LCD cannot be completed without it.

And now, with supplies gathered, we can begin to work on connecting our display.  However, its generally best to not go blindly soldering, so we will use a circuit diagram. As seen below;

(Source: LCD Smartie.)

If you’ve never seen a diagram before, Pin 1 of the printer cable goes to pin 6 of the LCD, Pin 2 to pin 7, etc. You’ll need to cut off the opposite of the male end on the printer cable. Using the multimeter, designate which wires go to which pins, then mark them somehow.

As for the other pins, VCC is 5v (we’ll connect this last), VSS is ground, the others are just data pins. Save the two that control contrast and back-light. Pin 1 on an LCD is generally shaped slightly different. Mine was a square hole instead of a circular one.

Quick shot of my *wonderful* solder job from 4 years back.

Assuming you have correctly soldered on your printer cable, you can begin work on the potentiometers. Using extra lengths of wire, solder your ‘pots’ just as in the diagram. On most it doesn’t matter whether the top or the bottom pin is connect to 5v or ground, Just as long as the middle pin is used for adjustment. However; its best to read the instructions that come with your pots just in case.

Finally we come to my personal favorite part of this DIY LCD. As Tim Allen would say, “more POWER!” I found this nifty trick out after reading several other technical websites, and in order to make the readers’ life simpler, Ill re-explain it. We will be using the extra fan molex connector, the pen (begin disassembling it – we just need the ink tube) and some of that extra wire.

Insert ink tube onto male pin. Push down all the way.

Pull out old wire.

Solder on power wire from LCD to the pin you just pulled out, reinsert into molex.

Everything should be wired up and good to go. Its suggested you put the LCD in a case of some form, but its not necessary. My first 2×20 LCD was held together with hot glue and cardboard. Granted, as you can tell I’m using a 4×20 now, the 2×20 didn’t last too long. Plug in the printer cable to your computer. Punch off a PCI plate and string your molex connector inside your case and find an empty connector. If everything went correctly, when supplying power to the display, you will get a test screen (below) and can move onto software.

Working default power test screen.

The software used is what truly brings this together. There are about a dozen different programs one could find to drive their display, however, my recommendation is to use LCD Smartie. Its been a while since it was updated, but it still runs perfectly on all Windows OSs except Vista 64-bit (more on this in a minute). Once the software is downloaded and extracted, simply run “LCDSmartie.exe”. A box will pop up, click “setup”. Here you can change what is displayed on the screen including everything from HDD space to CPU usage to Winamp etc. But first you must change the display plugin from default to HD44780.dll. Then change the screen to the current size you have wired up.

Choosing HD44780.dll

And selecting my screen size.

Vista 64-bit users are special. Without going into details, Vista 64-bit doesn’t allow software that isn’t properly signed by Microsoft to run, but don’t be alarmed. All your hard work can still be utilized, but a different driver dll and a few other settings need to be changed. Download a 64-bit version of InpOut32 here (Thanks Highrez.co.uk). Extract inpout32.dll into the same folder you extracted LCD Smartie (make sure LCD Smartie is not running at the time), replacing and updating the file.

Continuing with Vista 64-bit, do as instructed previously setting the display plugin and screen size. Next, navigate to your Printer Port Properties: Start> Control Panel> Hardware and Sound> Device Manager> Ports> Printer Port> Resources (tab) and copy the I/O range settings to the Startup Parameters box. (As seen below.)

Your I/O range might be different.

Clicking apply, you should successfully have a flashing mouse scrolling across your screen. If not, don’t fret, make sure your contrast isn’t set so low you cant see whats on the screen. Also check your solder connections, making sure none have possibly broken loose, and double check you have the right dll, screen size, and other settings.

If all is good for you and your display is up and running, then congratulations. Flip through the screens and you will quickly learn how easily it is to program your own. There are hundreds of possible screen setups you get to create and even more with user made DLLs.

Unfortunately, this tutorial is finally over. Hopefully, you were able to grasp a better understanding of electronics, learn a few skills, and have some fun. If you’re having problems, feel free to leave a comment or send me an email. Suggestions and comments are welcome as well. I leave you now showing a couple of screens I use.

CPU Usage.

HDD

Big clock using the bignum plugin.