What I used:
-1 x 12" x 7" piece of aluminum flashing (to extend for mouse area)
-1 x 5.5" x 7" piece of aluminum w/holes (used to hold boards)
-1 x large stiff door hinge
-1 x LS30 45º angle "Strong-Tie"
-1 x U-shaped metal fence post bracket (size to go around a tripod leg)
-1 x 2" bungee cord (used for extra stability)
-6 x nuts/bolts thin enough to go through holes of holed-aluminum
-(optional): Black Spray paint, sandpaper, Dremel cutter to trim off ends of bolts
How its done:
1) Place the U-shaped post bracket around the tripod leg, Put ends through both the Strong-Tie and the door hinge (with Strong-Tie underneath the door hinge). Attach the nuts that come with the bracket and tighten.
2) If you are using the extra aluminum flashing (as I did) for a mouse area, place this underneath the holed-aluminum. Make sure both are on top of both the Strong-Tie and Door hinge as those are what hold up this part. Bolt through both pieces of aluminum and onto the door hinge (DO NOT bolt onto the Strong Tie if you want to be able to raise the stand as I show in one of the pic)
3) After these are fastened securely hand move the Strong Tie to an angle that will allow the laptop to sit level (mine is not quite 90º) and support the above aluminum table.
4) Use the bungee cord to loop around the top of the tripod leg and into the top holes of the door hinge for added stability (additional option is getting a smaller post bracket for these holes)
5) I then spray-painted everything black (though I would suggest to do this before you start, used a Dremel cutter to cut all the bolts flush to their nuts and then sanded the mouse portion (as I have a laser mouse the flat black was absorbing too much light and the mouse wasnt working. I also have Velcro squares on the bottom on the laptop and top of the holed aluminum for a little more stability for the laptop and I used Velcro to mount my USB hub below the new stand onto the leg.