Let's Make Robots!

Perpetual Ball Roller

Rolls a ball around a ring

This machine is controlled by a PicAxe Microcontroller. A servo (used for steering in R/C cars) is used to tilt the track for a ball to roll round. The degree of the tilt can be controlled by a potentiometer in manual mode or in automatic mode preset instructions on the microcontroller tell the servo how to move.

I struggled to find a name for this. I eventually settled on Perpetual Ball Roller. I like the "perpetual" part because it gives an idea that the ball will just keep going round and round but the name doesn't really describe what it is. I can't believe someone else hasn't made something similar but because I had no idea what to search for on Google I haven't found anything. If you are wondering what it is the best thing to do is it to watch the video. I'll detail some of the features here incase I didn't mention them on the video or you can't watch it.


There isn't really a simple figure of how long it took to make but I'll try and give a rough idea. The main construction of the frame and ring took about 3 hours. I'm not too bad at this kind of work as I have done quite a few similar things before. It took about 1.5 hours to wire up a very simple Picaxe circuit with servo and potentiometer and put the code on for very basic control with no limits. I realise this might be a bit slow to some people but I tend to take electronics slowly. I then spent another hour mounting the servo properly (before it was held down).  For the actual coding of the different routines maybe 5 to 6 hours. You could do these in a lot less time (2 hours easily) but I was in no hurry and wanted to experiment. All those add hours add up to 12 hours (rounded up!).



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Working like a small collider ))) Very cool thing!

I never thought of it like that, thanks!

in that way you can continue to build additional circles and it can work like a railway )).

Thanks very much for showing me your one. You're the first person let me know you've made one so as far as I am aware there are now two in existance.

5 stars for the inspiration!!! 

very original piece of interactive art, or should I say kinetic sculpture?  ;)

Awesome! Put some polished wood or something around it, make it look really nice and tidy, and you would have yourself a piece of modern art.

Inspired. Definitely.

I'd like to see a fersion with feeback, so the PIC "knows" where the ball bearing is. Perhaps a set of wires positioned equally around the track which shirt as the stell ball passes them.

The idea would be: if the ball is stopped, the pic would recognise when to start jiggling it because it's moved away from its rest position. This wouldensure it doesn't waste any "jiggles" and that it doesn' "jiggle" too fast initially. (It would also enable the figgling to sotp if it throws the ball off!!)

The ideal feedback mechanism would be a principle called Time Domain Reflectometry. Maybe need a faster processor for this one...!


inspiring...  i have to stop to make sophisticated roves, it start to bore me


Very abstract - super design - brill idea.

I am not suprised it took 3 hours to assemble the base unit, the geometry of the metalwork and alignment must have been a nightmare.

How did you join the metal wire? .... (with solder !) - as i need to make some similar ring for another project out of galvinised wire.

This would be a good talking piece as a dinner table decoration. It would certainly catch peoples eyes in a shop front too.