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WQUXGA Laptop Screen Array

Build by David McKinnon           novak |at| gekkoscience.com

If you want to get a high pixel density desktop monitor, you're mostly out of luck. High resolution monitors exist in abundance, but the high resolution ones are usually larger so as to maintain about 100 PPI or less. With the advent of so called "retina" screens, there are plenty of high pixel density laptop/tablet/phone screens, however. Even older screens on laptops often had full 1920x1200 screens in much smaller sizes than the 20+ inches usually available for desktop monitors. I wanted to build a high pixel density monitor array for my workbench out of laptop LCD displays.

The difficult part is finding a way to control the laptop screens. Newer laptop screens use eDP, which is essentially displayport, and all you need is an adapter. Of course, these adapters don't actually exist, so you'd need to build your own. Older laptops use LVDS, which requires a separate driver board. Fortunately, these driver boards are pretty easy to come by. Most of these screens only go up to 1920x1200, but that's still a pretty good resolution. I decided to use these older panels, which makes it pretty simple to build. The controller boards I used were RM5451 from NJY Touch. You can get these boards on their Ebay store for about $35, depending on what all cables you want to come with it. The screens I chose based on the ability of the boards to drive them were LP171WU1, which is a 17 inch 1920x1200 panel, which gives an approximate pixel density of 133 PPI- Not super high density but about 1/3 more than I could get from a commercial screen. The screens themselves cost a little over $80 new inside the US, so there are probably cheaper options available, but the price of each screen is about $120 of electronics, which is also cheaper than most 1920x1200 screens that are commercially available. If you add in the cost of mounting hardware it's a little more but still under $150 each.

The first step is to build the mount to hold the screens. The screens are each roughly 1/4 inch thick, and to protect them a 1/4 inch sheet of polycarbonate was added over them. The screens and protective polycarbonate were mounted in 1/2 inch aluminum channel, which is pretty easy to find at a hardware store. The bezel on each screen is 1/4 inch as well, which unfortunately means that the channel was deeper than the bezel, and the channel has to be cut down to be no more than 1/4 inch deep. A bandsaw works well for this.

Now the channels are cut to length and mounted to 1x2 boards, which go around the outide of the array. The channel is mounted by using countersunk screws in the center of the channel, which keeps the screws from sticking out and interfering with the screens fit.

The polycarbonate is cut to size using a table saw and everything is checked to make sure it fits well on the back, which is a piece of plywood. Note the general arrangement of the screens and channels- Each polycarb sheet covers two monitors (either the left or right side), and two pieces of channel are used back to back in the center to keep both halves together. These center channels will be attached to the back via band clamps. Now the 1x2s are attached to the plywood backing via wood screws. it's a good idea to pre-drill the 1x2s to keep them from splitting.

Next the holes for the cables are drilled. Large holes using a center drill are placed near the top left of each screen for the LVDS ribbon cables and small holes are placed near the bottom right for the inverter backlight power supply. Holes are drilled for the band clamps which mount the center channels, and slits are cut with a dremel in the back of the center aluminum channel to allow the band clamp through.

Next, the controller boards are mounted on the back of the plywood, using small wood screws. Note that the small inverter boards are near the holes for the inverter cables and the main controller boards are near the holes for the LVDS cables.

A couple of legs are built to mount to the sides of the array.

Now the entire thing is assembled- all screens are inserted, the polycarbonate is unwrapped and inserted, and the inverter and LVDS cables are connected in back.

Now the boards need to be powered. The boards have a simple bullet plug for power, so a PCIE extension cable is connected to bullet plug cables, and power can be run at high efficiency from the power supply that is already required for the computer via an 8 pin PCIE power adapter.

With this, it's time to figure out how to drive the array. I have a AMD Radeon 7970, which is able to drive six screens, however, anything over two screens requires active mini displayport adapters. Once it's set up then you need to configure the card correctly to use all four screens as a single workspace. For me, this means configuring xorg.conf. Shown below is the proper tecnique for doing this.

Here it is in all its glory, playing back video at over 4K resolution. Yes, scaling UP a 1080P video by a factor of two. The mounting is not beautiful- rough lumber, but it's is perfectly sufficient for a workbench machine. At some point I need to see if I can put together an eDP adapter and get a really high pixel density screen set up.

Questions, comments, corrections or humorous mockery? Email me at novak|at|gekkoscience.com.