Our marble machines are
battery powered using standard AA batteries.
This module works great. Balls roll and roll and roll.
I like this one. Sometimes the drop into the half pike just bounces in the middle, instead of rolling in the pike.
This printed out fine for me. All parts fit and worked smoothly. I had printed other Modules from Out of Marbles and they also worked great. This was well worth the price and I wanted to pay for the work done on these units. I bought the hardware for Amazon. I did add weight to the left flipper as it would not drop with 100% in fill. It now drops with 3 marbles.
The two wheeler is a bit more difficult to print and make work than the others I've printed. The two issues I had were: 1. The marbles falling out between the wheels and the guard rail, and 2. the path needs to be perfect for the marbles to roll to where they should. On point 1. I fixed the problem by creating a spacer to go on the pin supporting the wheels. This moved the wheel closer to the guard rail and it solved that problem. On point 2. I was having a bit of a problem getting the long path across the top to print correctly so the marbles would roll to where they were supposed to go. I solved this problem by downloading the PrusaSlicer and using it to slice the files. I'm not sure if that was correct way to fix this, but it worked and now The Two Wheeler works perfectly!
Needlessly high tolerances, parts that do not fit well, price that does not include everything needed. Actually I'm not sure if I will have the nerves to finish it.