Motor base for 3D Printed Marble Machine #3

thingiverse

https://youtu.be/s7StitvMJo8 This model is a budget-friendly motor base designed for the impressive Tulio marble run. You can either download the original model and use OpenSCAD to recreate the STL files, or I have included the updated STL files if you don't have access to OpenSCAD or prefer not to use it. The motor used is a GA12-N20 (Search Google for suppliers. Amazon offers quick delivery but at a higher cost. AliExpress provides affordable options but with longer shipping times). In the video, I utilized a 6V 200rpm motor, although it will operate slower since I'm providing only 3V power. A slower motor might be more effective as the faster motor causes marbles to catch up with the slowest one over time. The motor should have a 3mm shaft variant. The motor coupler features a D slot, so be cautious when attaching it to the motor. The top of the motor must align flat with the base's top surface. For battery contacts, I used a spring from Home Depot, cutting it in half and bending part of the spring to accommodate the battery spring mounting groove. The non-spring end can be any material that can be soldered to; I utilized a cut and straightened hose clamp. The power switch is simply what I had available. I clipped off all but two contacts. You may need to modify the base model if you cannot find a switch of similar size. Solder each motor connection to one of the cut springs, then insert the bent-out part into the narrow slot in the battery holder to secure it in place. The switch should have its terminals connected to one of the flat connectors inserted into the narrow slots as well. With my switch, I was able to bridge each terminal directly to one of the battery connector strips. Be sure to use the correct terminals on the switch, i.e., those that short when the switch is 'on' and are open when it's 'off'. Batteries can be inserted in opposite directions. If you have already printed the main track, you will need to cut a hole in the bottom to allow the spiral to drop through or for the coupler to fit. I found it easier to assemble with the hole completely open, but a smaller hole might suffice for just the coupler. Note that the screw is modified and should be aligned with the smaller triangle pointing towards the motor and the original cap opening at the top. The base is customizable, and you can change the holes in the base. I preferred circles, but setting the number of sides to 3, 4, 5, 6, 7, or 8 also looks appealing.