Well, that’s not entirely true. I would like to avoid making a big mess out of developing the PCB, and would prefer to do a few project boards at a time in order to minimize the chemical wastage. There are a few interesting DIY midi projects that I might want to try out, and would thus require custom boards for. Fortunately those projects have already been designed, so it wouldn’t be too tough to take on.

In the meantime, I’m working on my music again. I almost forgot how good it feels to have the creative juices flowing. I’m definitely not as good as the visual arts as I am at music (note this webpage’s lack of design), and so I should stick with what I know.

Stay tuned for further details about the music. I may post some stuff online when it gets closer to completion. Caution: I work quickly.

So now I have two options:
1. Continue to lay out the PCB given my new, successful design.
2. Perfect the circuit to include a PIC 16F84 that handles the centering of the displayed image, and then lay out the PCB.

Decisions, decisions. I think I will have to choose option 1 due to my lack of time right now. It is a little annoying to have the image chopped off on the left side of the TFT due to one control line on the interface that I’m unable to drive properly. Then again, it only takes about 20 minutes to throw together a little program to run on the PIC that’ll drive the ENAB line of the TFT. We’ll see what I can pull off for the time being.

You probably already know where the panel came from, so I won’t repeat that.

The 50,000-foot view of the project is that I want to take an analog VGA signal coming out of a plain ol’ VGA card, and pass it into an old TFT LCD panel via its digital interface (6-bit RGB interface for a total of 512 colours). To simplify the project, I only want to use one bit per colour (8 colours total) so I’m not messing around with so much componentry.

The first challenge was getting power to the LCD’s backlight. As we may already know, there’s a CCFL (cold-cathode fluorescent lamp?) backlight on pretty much every TFT LCD out there — it provides the “backbone” of the bright light that emits from your LCD. Powering one of these things is a challenge as it requires about 400V (at about 2mA), with a kickoff voltage of about 1500V. I managed to find an inverter from my local electronics store that could supply a 900V kickoff with a 400V output, and after finding just the right wall-wart to power it, that did the trick.

After seeing a constant backlight, I worked long and hard getting the panel interface “buzzed-out” (using the continuity function of a multimeter to find out which pins correspond to which loose wires). After that, I attached all the loose cables to my breadboard containing a simple amplifier/inverter circuit and hoped for something on the screen. Nothing.

In the middle of all this, I grabbed a used oscilloscope on eBay (fantastic deal) and tested my circuit out the wazoo. Needless to say, the scope said it was all working perfectly. Whatever

I was convinced that everything was shot to hell (burnt panel, or destroyed circuitry somewhere), when I decided to just check the breadboard connections versus the pins on the interface connector on the panel. Sure enough, something wasn’t right.

I actually managed to label all the loose wires BACKWARDS! That’s right, pin 1 was labeled 15, 2 labeled 14, and so on. At least pin 8 was okay. ;)

Anyway. It now seems to work, as you can see in the picture. I rule.

Fast-forward a few days, and I have the tried-and-true pcb available to me. I compiled it quite easily out of the box, and it runs decently under X11. It’s not perfect in every way (some UI quirks due to X11 + Aqua interaction) but it works very well for what I need to do. Not just that, but I am able to create new element files for all my weird parts that I pull off of other boards and find datasheets for, and my netlists work very well. Apparently if I want to use the the gEDA package, I can easily export the files from the schematic capture software directly to PCB. w00t!

Yay for Apple and their UNIX compatibility!