Although I am fairly well set up for working with multiple computers on a single monitor (using a 4 channel KVM switch), from time to time I have an extra equipment, be it a PC, laptop, or any other consumer electronic device that needs a display to interact with it, that is always a pain to hook up with a monitor or TV for trouble shooting. As I recently had success experimenting with LCD panels salvaged from old laptops/TVs, I decided to make a permanent test rig for such occasions.
As the base of the whole assembly, I used a sheet of hard paper that once was the back panel of an IKEA picture frame:
- It’s just the right size: The LCD panel and driver/controller boards I had lying around just fit on it nicely.
- Strong enough to hold itself and all the parts I had in mind, but, at the same time, it’s very easy to work with – After all, it’s made of paper.
- Cheap: I had it as a leftover part from one of my Digital Picture Frame projects. So I won’t get too mad if I mess up something.
For stand-offs and screws (to hold the driver/controller boards in place) I used some bits and pieces from the library of PC case screws, etc. I have accumulated over the years building countless PCs.
|3mm copper stand-offs|
To hold the LCD panel in place I used some self adhesive Velcro strips. The advantage of this is that I can easily replace the LCD panel if needed.
Apart from these materials I used a Dremel to pre-drill the holes for the stand-offs.
I started by laying down the components on the base in a way I thought was practical.
Then I attached two Velcro strips to the top and bottom, i.e. long edges of the back of the LCD panel:
|A close-up of one of the Velcro strips attached to the back of the LCD panel.|
Next I removed the protecting tape from the Velcro strips (on the LCD panel) and I simply placed the LCD panel on the paper base. This will ensure that the receiving Velcro strips will be perfectly aligned with the mobile ones.
|Velcro strips firmly in place. Also, the location of the stand-offs marked.|
With a pencil or felt tip pen I marked the spots for the holes to be drilled for the stand-offs. I pre-drilled the holes a bit with a Dremel then I screwed in all the stand-offs:
|All stand-offs in place.|
Of the three PCBs I mounted the display driver PCB first, as it had the most “dependencies”: cables, stand-offs, etc.
|LCD driver board firmly in place.|
Next came the high voltage (or inverter) PCB. The LCD panel has a very short lead for the inverter connector, so this PCB had to be mounted very close to the LCD panel:
|Inverter right under the LCD panel.|
Last one was the user interface panel – this one has the on/off LED, as well as the buttons to manipulate the OSD menu:
|This control panel is now in the lower left corner of the assembly.|
|All three PCBs mounted in their places.|
Since I used an LCD driver board that has HDMI, composite video, RGB monitor inputs, I now have a test rig that is able to display almost any kind of video source I throw at it. In the below example I am using it for the initial configuration of a headless Raspberry PI system: