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.

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