Saturday, August 3, 2013

TFT LCD Project

I got a broken Fujifilm digital camera from the local hackerspace 'purgatory' shelf. After pulling it apart, I immediately became fixated on the possibility of learning how to drive the LCD. Below are some notes on the process. I started know absolutely nothing about this device.

Step 1: What is it?
The only identifying mark on the LCD screen was a set of numbers on the back. After some google searching, I found a Russian language website that listed parts in cameras, presumably to help with home repairs. They also linked to a number of repair manual pdfs. The camera I had was not there, but the information there indicated that some of the other cameras might use the same LCD.

Step 2: Best Guess for Pinout
I counted the tiny contacts on the ribbon cable and noted positions of the dummy pins (the pins that don't lead anywhere). I eventually decided that my most likely pinout was the same as the one in the Coolpix L1000 (see left diagram).

Step 3: Identifying the Connector
There was no way to disconnect the ribbon cable connector from the board. It was far too flimsy and would break or melt when I tried to desolder it. I don't remember how I figured this out, but probably by forum trawling (not trolling) I was finally able to identify the part.

Step 4: Driving a TFT LCD
By this point I understood that my LCD was called a "TFT LCD." I found some resources that described how these devices work. I also found a pdf for an ANDpSi025TD-LED 320 x 240 Pixels TFT LCD Color Monitor that is probably identical or similar to my LCD. From all the documents I found, I had some good suggestions for circuit diagrams and driver code.

At this point though I stopped and decided I couldn't justify the time or money needed to finish this project. I didn't have enough items in my cart to justify the Digikey shipping costs. I needed to make a breakout PCB for the connector. Besides, there were affordable TFT kits available online, that would cost less than my Digikey order and PCB order. Maybe one day, if I'm already sending out a PCB and Digikey order for some other project, I'll take the time to finish this up. The main incentive is that this TFT LCD is a bit bigger than the ones available in kits.

Laser-cut Shirt (aka first sewing machine project)

I have started making shirts. The process involves laser cutting pieces and assembling them with my new sewing machine.

Step 1: Choosing a machine
  • I learned on an Emerald 116 Husqvarna Viking, an 'analog machine'
    • The foot pedal sits inline with the power cord, controlling motor power directly
    • Knobs control the stitch type, width, length
  • The most widely/highly reviewed machine on Amazon is the Brother CS600i, a 'digital machine'
    • (1,770 reviews averaging 4.4 stars at time of writing)
    • LCD display is very convenient for choosing stitches, lots of stitches to choose from
    • Will not allow 'mistakes' like trying to stitch with the presser foot up
    • Foot pedal connects optionally via standard 3mm audio-type connector and port
    • Competitively priced. I paid $155 for it, but I see it has dropped to $140 at time of writing
My one suggestion for improvement of the machine is the addition of a USB port and the option for users to upload new custom designed stitches onto the machine. That would be so cool.

Step 2: Fabrics
JoAnn's had some knit stuff appropriate for clothing, but not much. I have to find a better supplier for the next round.

Step 3: Designs
I used my point and shoot to take pictures of the front and backs of some of my favorite shirts. Then I went in with Corel Draw and created designs (cloning the left hand side from the right for symmetry). Finally I added outer contours for seam allowance and scaled the whole thing appropriately. I did an okay job but should have left a larger seam allowance.

Step 4: Cutting pieces on the laser cutter
On very low power, I cut all the parts out for the shirt using the files I created in Step 3. Because of the laser cutter bed size, I had to separate the shirt into 32" by 18" pieces. Therefore my favorite theme for this type of design is 'colorblock shirts,' though this shirt was not one of those.

Step 5: Sewing
This was by far the most difficult and time consuming step, of course. My first trial ended up wearable but definitely could use improvement. Here's a photo of the shirt and the design (the white thing is just an undershirt that I already had). Again, once I get a license for my Corel Draw I will clean up the files and export PDF versions for sharing.

Music Box - Theme from Being John Malkovich

The big existing music box composition app is designed for the more ubiquitous 15 note diatonic DIY music box by Kikkerland. The source code is not available. Also it is for Android only.

The next music box project will have to be writing some music box composition software. This took forever using a mix of free tools not designed for the job at hand. You can see my extensive notes all over the punch card.

My music box software desired feature list:
-Platform independent, written in python
-Distribute source so others can modify it for their particular music boxes
-GUI allows user to click and drag holes on a virtual punch card
-Allow for variable speed playback to previewthe sound, pause and play with easy keyboard shortcuts
-Highlights timing issues (minimum spacing for repeat notes due to the music box mechanism)
-Creates a vector format file that can be printed (for easy hole punching) or lasercut

Bamboo Pentagram of Circles Trivet

Trivets, coasters, candleholders, and other pieces are good ideas for laser cut gifts, except for the fact that most people already have been receiving those sorts of things for the holidays for years, and have more than they know what to do with.

Except...students! In general, I've found that single people who are students or who were recently students don't usually have a lot of this stuff.

In fact, I fit that description. I don't have any trivets. I have candle holders admittedly. But no trivets. So I made this out of a bamboo cutting board. You can find bamboo cutting boards for cheap at stores like Home Goods.

I found a png on Wikimedia (an amazing resource for png and svg files like this) and spent a few hours in Corel Draw making the vector cut file.

I need to get a license for Corel Draw but once I do that, I will clean up all my files and export them as pdfs to share.