To build this Marble Machine I took a look at several existing marble machines, one of them can be found on references.
First I used SolidWorks to design each piece and then I made an assembly to see if everything was going to work well. I was expecting to use bearings on the center of the wheel and also a small gear attached to a small electric motor and that is why the wheel looks like a gear. Additionally I designed the machine and the press fit mechanisms assuming I was going to use a 5mm sheet. I couldn’t find a bearing that was the right size and I also I had to use a 4mm wood sheet, that is the reason why I had to make several adjustments so it would work. Also I didn’t find an appropriate motor so I built a simple crank. The SolidWorks Design can be seen in the picture below.
The next picture shows the actual piece, I decided to hide the ramp and that is why I have vinyl covering the sides.
References