I based this instructable on jumpfroggy's one (https://www.instructables.com/id/A-better-laptop-stand-for-bed/) but made some emproovements to his design. Reading the comments tho that instrutable it turned out that the joints where a week point, plus it gave only the possibility to act on one angle of the structure. Many of the sugestion from the readers focused on a different way to position that angle and keep it there.
On my side I whanted something that was sturdy enough and that would allow me to adjust the table both on height and inclination at the same time. So I came up with this "X legged Laptop stand".
You can see in the pictures the different positions it can take allowing you to adjust it in heigth ( for your legs or belly ) and inclination (standing or laying)
Step 1: Materials and Tools
WARNING: Metric System ahead.
1) 2cm pine wood board (see later for dimensions)
2) 2cm x 4cm pine wood strip for the legs of the table
3) 4x iron/steel L-Brakets with appropriate holes pattern on the flat side
4) 4x 8mm diameter nuts and bolts
5) 2x iron or steel needles, 3mm in diameter or similar
6) 16x 1,5cm wood screws
7) 2-4x 2,5cm wood screws
8) a 2cm x 2cm wood strip (20 to 30cm should do)
WARNING: Power tools involved: use protecion and proceed responsabily
1) power saw
2) power drill
3) hole saw
4) sanding paper and sanding disks
5) screwdrivers, bliers and other hand tools
6) pencil, measuning tape
Step 2: Measurament
On the upper face the board needs its surface to be large enought to hold your laptop
and, maybe, a small mouse pad or the space for a portable hd or your coffe mug. On the lower side you whant it to be large enough so to have you legs confortably under it or your stomach.
Try out the position you'd like to have while using this table and measure it.
Add a total of 10cm (5cm per side) to leave some space for installing the legs.
My board, for an example il 45 cm whide.
The height of the board is easy determined. Most of us will have nothing more than the PC itself, so measure the short side of your laptop and add 2cm for the rim that will hold it in place.
A little more measurement is neede here. A friend might be of help holding the board in different positions while we measure.
You whant the legs to go from one corner of the board to the ground (cough or bed) remaining on the same side. Take care that the leg must allway cross the mid-line of the board so to give it a nice wide base. On the other hand you don't whant those legs to bee too long otherwhise they might not fit your sofa dept!
All 4 legs do not need to be equal: "back legs" (those that start on the far side an come closer to you) are longer than "front legs" (those that start closer to you and go down in front of you.
In my case the front legs are 45 cm while the back legs are 35cm.
Step 3: Make the Board
Make the handle: take your hole saw and make two holes parallel to the long side. Centers of the hole should be as far as the width of your hand, say 8-10cm. With the power saw connect the two holes removing the wood in between them so to have a wide cut. Sand the inside of the handle to avoid getting splinders in your hand.
Make the areation holes in the board: In order to allow more ventilation to the lower side of the laptop you should make holes in the board. You may choose to apply the same process used for the handle, like I did, or you may just go crazy with your hole saw and make openings here and there. BEWARE: you laptop probably has small rubber supports, when making areation holes be sure that the supports will not fall into the holes. Also, if your board si wider that the laptop width, consider where the supports will be when placing the laptop in left, right and center of the board.
Step 4: Make the Legs
At one end of the legs make holes for the support. Place the hole so that it has the same distance from the sides and the end (so that is is in the center of the circle resulting from the rounding of the leg). The hole dimensions depends on the size of the nuts and bolts you will use (8mm in my case)
Make the holes in the legs: couple same legth legs one over the other and make 4mm wide holes in the center line at a 2-3cm distance. Putting one over the other will save you time and get sharper results. You may also whant to widen the opening of the hole with a cone sanding drill bit, to make it easier to adjust the position later on.
Step 5: Attach the Legs
Attaching the legs is easy: fix the L bracket to the board with 4 1,5cm wood screws (this might change depending on the type of L braket you are using), those screws need to be shorter than the thickness of the board to avoid trepassing it. Attach the leg to the L braket with the 8mm nut and bolt. The leg should be easy to move up and down.
Please note that the L brakets are mounted in opposite directions, so to allow the legs to be as close as possible. Back leg's brakets are facing out, while front leg braket are facing inside.
You may also use a washer to save the wood should you tighten the bolt too much
Step 6: Make and Attach the Rim
To attach the rim use wood glue and /or longer wood screws. Use 2,5cm screws, or anyway a screw that will trepass the board but not further than the rim. Align the rim to the limit of the board.