The clock is ticking, a month to go, that is weeks now. Here you see the design starting to take shape. Playing with the rack slides, my first idea of mounting them under the platform just didn’t seem like a good plan as they have most strength in the vertical plane. I’m still worried about toddlers hanging off the platform, so it needs to be able to handle abuse.
I’ve based the design size from the size of the square white blocks of paper for notes. I realised by using these blocks of paper I can prevent myself from having to cut hundreds of sheets of A4 down to small squares myself. So the design is now all based on the size of those paper blocks.
I have also obtained four blocks from ASDA, for £1 each with another that has a plastic holder for the table on the day. This should be plenty of paper for this year.
Below you can see the platform taken shape. I left a large base at the back to allow the platform to be G clamped to the table when in operation to prevent it from tipping when people press down on the front of the platform.
The platform moves in and out really smoothly and pretty much frictionless. The slides have a auto click at the back of them that stops it opening again without a little tug.
I know it does not show, but a lot of thinking has gone into this base, the side walls should simply screw into the large wooden batons, that are big enough not to split and offer good support for the rest of the structure. The front should align just right with a slot in it for the draw.
Later on this evening I got more done. Below you see the slot for the drawer and the sides cut.
For the height I rigged up the Pi camera and by hand worked out the focal length needed to get a good, in focus, but filling the frame picture. Then added on room needed for camera and the cable to come out the back of the camera.
Above you can see the microswitch and the trial paper on the platform. The square blocks will go in the top corners to support the lid and sides. Access holes will be required for the cables.