This is my first instructible so please let me know if there is any additional info/images you'd like and I'll throw them up ASAP.
After hooking up my desktop PC to my main TV as a media center/gaming system I soon realized that there is no comfortable way to use a mouse and keyboard for long periods while making cad designs or playing games. Leaning over the table kills your back but having the keyboard on your lap with the mouse on a pillow is unstable.
The desk arm is designed to provide a stable work station from a comfortable seat while still being able to fold away for easy ingress/egress. It incorporates an articulated arm to easily swing out over your lap with variable height and desk angle, a slide out magnetic mouse pad so the mouse doesn't slide off while the table is moved or at an angle, articulated LED desk lamp, 5 USB charging ports, wrist rest positions and a rubberized easy grip coating to keep the keyboard or whatever you want on the desk area.
Step 1: Materials
What I used:
NAVpoint laptop stand
2 center drawer sliders
1'x1'x1/32" steel plate
6/32"metal screws with nuts (to fit through the holes in the stand's plate). Get plenty of each size between the shortest to 1/2" in length.
Rubber spray on crack sealant found in the spray paint section at most hardware stores
anker 5port USB charger
Ivation desk lamp
Step 2: Installing the Arm
The arm didn't fit on my table so I cut into it. This gave me an opportunity to add the powered items without visible cables to the wall outlet. If you don't want to or can't, I would suggest leaving the usb part out.
For non-destructive install, make sure your mounting surface has a flat overhang at least 3" deep.
Step 3: Working With the Plywood
The plywood has 3 layers; the top layer is the desk/keyboard holder that slides to the side to reveal the center layer which is the mouse pad and frame and the bottom layer is the mounting surface that stabilizes the section of mousepad that protrudes over the right side of the stands metal frame since the existing holes in the stand would otherwise require me to drill through the mouse pad plate for the two right hand fastening points. The 1x1 metal plate has 4 holes at each corner connecting it to the center layer with 4 short screws.
Pick a desk size and shape
Cut out an upper desk ensuring that it is long enough for your keyboard. Make sure the bottom layer is smaller than the center layer and that it fits well over the arms frame.
Center layer: Make sure the center layer is larger than the mouse pad plate so you don't have to worry about protruding sharp edges. Give at least 4" to the right of the mouse pad plate so there is room to mount the sliders.
Bottom layer: this won't be seen so I just used a rectangle. Line up the right side with the right side of the center layer when picking a size.
Line up the bottom plate so that it sticks out as far to the right as you want the desk and drill 6 holes so that they line up with the holes in laptop holder surface with 4 on the left to also be used for attaching the slider and two as far to the right as possible for better stability. Put either one or two in on the right hand side past the end of the mouse pad plate to attach to the center layer to.
In the center layer drill match all of the holes besides that are in the bottom layer. The top layer only needs 4 but you'll want to wait until you've cut and drilled the sliders first to make sure it fits
Step 4: Sliders and Assembly
This is tricky and I'm on the road so I'll have to leave it at a general description until I can get home and add more pictures.
The wide sections of the sliders are fit to the length of the upper layer but their right ends need to be cut to allow the insert to slide in and out easily. To remove the insert the first time pull up and out on it in the center of its travel. Cut the insert to the length of the left zone of the center plywood pice that it will be attached to. Carefully drill holes in the insert to match the hole locations on the center plywood pice so they are horizontal. Mount the wide sliders on the top plywood pice so that the cut sides face the left with some wiggle room for alignment. Attach a small thin pice of plywood to the furthest left underside of the top plywood pice to act as a slide stop. Slide the top onto the inserts and tighten the slides on the top pice. Disassemble, paint, reassemble, glue some small weak magnets on the sides of your mouse, add hand rests and electronics. Enjoy your new desk!