DIY add touch screen to a 4.4″ LCD display.

I had installed a parking camera in my car, which used a display like this one mounted right above the rear view mirror. That is a great helper when parallel parking in tight spots and improves safety.

Those displays have two inputs, so I had attached a android stick with a HDMI to Composite video adapter to the second video input of this display and use it as a music player. The radio in the car only played CDs. The whole thing is controlled through a remote control with a USB dongle, but I wanted to have a touch screen as well.

Here is how I did it:

Disassemble the display, and remove the LCD screen from the front plate. It is hold by double sided sticky tape.

Then remove the glass from the bezel, again hold in by sticky tape, and cut out the transparent part using an X-Acto knife. First drilled 2 mm holes in the corners and then pass with the knife until the plastic is cut. The resulting black frame is going to be used again and the cut out window gives access to the touch screen.

Next step was to glue this frame to back to the bezel with some super glue and spray paint the front in satin black to cover some scratches and other imperfections.

Next place the resistive touch screen in and the LCD on top of it.

The touch screen on the picture above came from China with a controller. It works perfectly under Linux on a Raspberry Pi, but does not work with Android. Thankfully there is a solution, there is a replacement resistive touch screen controller made to work with android. It uses a ready made Arduino module. One can be found on E-bay or here.

Next attach the board to the back of the LCD with some thick double sided sticky tape and directly solder the connection with some thin wires from the board to the touch screens flex cable. Solder the USB cable directly to the board as well and secure it with some hot glue.

All that is left to be done is to attach the back lid. It has to be modified slightly though. What need to be done is to shorten all posts that touch the back side of the LCD with the thickness of the touchscreen. Then screw it back in place.

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