Ball Race
Ball Race
This is a copy of a ball race I saw one day at a career fair from a 3d printing firm. I was told it was a “waste of time” to print but ball races are fun! I also added ball return in the form of a photocell, servo, and magnetic arm. The inspiration piece did not have any ball return mechanism.
3d Body
Modeling this was a nightmare. I initially tried in Solidworks, but it does not like two surfaces that approach tangency to each other or any radius that approaches 0 so any swept cuts do not work. Swept paths do not work. Extrudes are difficult to slope. Drafts only work on one surface at a time (will not slope a path) Years after my initial attempt I had time and access to Fusion 360, and I ended up building it by creating a set of 4 base bodies and 4 turns, then doing several hundred move bodies, mates, and extrude from face commands. 90 second rebuild times on a good day. Not fun. I think it was around 18 months from first cad attempt to first print.
Wooden armed ball lifter with magnetic head
Ball Lifter
I had a few Attiny 85’s, a photocell, and some other random parts leftover from a previous project and this seemed like the perfect opportunity to use them. The code is quite simple; look for a drop in the light value on an IR sensor positioned at the bottom of the track, then run the servo back and forwards far enough to lift the ball and place it at the top of the track. The motor and controller run on 5v and a few hundred milliamps supplied from a usb cable so it can be plugged in to most USB supplies or a computer. I also installed a set of buttons to change the brightness threshold without having to reprogram the chip. The arm itself is made of a small piece of wood with a magnet fitted at one end and wired to the servo.
Internals! Brightness adjustment buttons are above the DIP8 chip