Friday, September 13, 2013

it works!

I got tired of waiting for the power supply and looked around the house for 12V power adapters, luckily I ended up finding one with enough amperage to power the LCD, it was being used by the Internet TV box. Before powering it up, I connected the LVDS cable from the controller to the LCD and checked the pins of the connector with a multimeter. I verified that all VCC pins were not shorting with GND pins or any of the data/control pins. I also checked that GND pins were connected together and the same for VCC - things looked good. Then I replaced the inverter coming with the LCD with the inverter packaged with the LCD controller. I hooked the power supply and a "no signal" box immediately appeared in the screen. Since it appeared to be working, I glued the inverter to the back of the LCD to make it safer, avoiding getting zapped and avoiding accidental shorts with the metallic frame. I finally connected the VGA cable to the laptop and voilĂ ! It is working.

I now need to build a decent frame for the screen to hold all the electronics safely inside. The inverter and controller board are quite thicker than the current (laptop-style) frame, so it will not be possible to use it. I will have to figure something out.. If any of you is reading, I would love some ideas..

Wednesday, September 11, 2013

LVDS controller received

Today I just received by mail the RTMC1B LVDS LCD controller kit. that I bought from ebay. Given that I bought this nearly a week ago and is shipping from Hong Kong, it arrived pretty fast!
You can see the LCD + controller above. They are not connected and powered (still waiting for the power supply) yet. I am not quite sure about the pinout since the proprietary connector that came with the laptop screen and the LCD controller's connector don't quite match. Here are individual pictures of each:
This is the connector (picture above) of the proprietary cable that came with the laptop screen.

This is the connector (picture above) of the cable and connector that came with the LCD controller kit. Looking at them, it seems that they share the opposite side of the connector. Tomorrow I'll need to check if the LCD controller and the LCD share the same ground and if there are any shorts between the GND (black) and VCC (red) pins of the LCD as indicated by the LCD controller seller.

I also managed to take a picture of the LCD model which I will leave here just for reference:

Thursday, September 5, 2013

Linux-based assistant for a MIDI digital keyboard.

How it started

It all started when a few months ago a friend of mine gave me a laptop LCD taken from an old Compaq Armada M700. The screen is 14.1'' and is in good shape (except the metallic bezel which suffered a bit while I took it apart):

Inside the laptop bezel there is still the inverter for the backlight and a Samsung LT141X7-124 TFT LCD. For some weeks I didn't have a clue what to do with it.

Mmm.. It looks good there.

One day when I was connecting the laptop to the piano keyboard for transferring some MIDI songs by USB, I realized that the LCD screen looked quite nice on top of the piano sheet holder. I wouldn't have to print sheet music anymore and could use Rosegarden to display music scores in realtime with the MIDI music - that would be awesome!

After looking a bit through ebay, I arrived to the following listing about an LCD controller board with inverter (even though I didn't need one) and VGA input.around $29 + free shipping. This would allow me to connect the LCD screen to e.g. my laptop. I messaged the seller asking if the screen model was indeed supported which he replied positively. He also added that he would flash the controller board with the proper firmware for my LCD model. I also ordered this power supply for the LCD controller, for around $7.

What now?

Now I'm waiting for the LCD controller board and power supply to arrive, it should take a few weeks. Then the plan will be:
  1. Test the LCD screen + controller board using the laptop.
  2. Find out which one, Rasperry Pi, Beagleboard .. is best suited for running GNU/Linux with Rosegarden, Timidity++ and a few other MIDI tools.
There is a lot more planned but for now that's all :) Feel free to leave me a message with suggestions and ideas.