Sunday, January 1, 2017


Jimmy Dodd, Pedal Powered Chocolate Wheel, 2016 from James Dodd on Vimeo.

This project was initiated by a radio station who were keen to develop something for a promotion together with the Tour Down Under.  They already had a thing called a Randomiser which is used to select random songs and wondered whether there might be a way to translate this into some kind of pedally outcome.  They were keen on the 'chocolate wheel' style which is like a wheel of fortune / spinner disc with a little clicker that eventually stops on a particular segment.  It was a project that I was keen on and was able to apply some existing knowledge to as well as explore some new trickery.  Here's a few shots of some of the process and nerdy bits.

First loose physical mock-up for client - also testing general overall size as the finished machine needed to fit into a specific space.
A bit more progress with the frame and support so that the bike is stationary and not touching the ground.  Features extra heavy duty sissy bar to be strong enough for full grown adults and frame extension on the front to accept a rear wheel.
Final assembly and all moving parts testing before finishing.

 It was nice to work on a job with a decent budget, allowing me to have everything powder coated.

I've been practicing a lot more design for laser cut outcomes over the last few months.  This is a pic that shows all of the construction lines with all of the various parts layered up with all of their intersecting fixing points.  This build had a bunch of laser cut bits to facilitate a main MDF disc that was painted up and all of the divisions and fixings for the perspex face that has slots for various tickets to be put in and out.  I also had a number of alloy discs made that allowed me to fit to the pre-existing parts on the axle and discs to mount a chainring for driving everything.  I used a go-kart axle kit for this job that came with pillow block bearings, hubs and axle mounts that became adapted to fix to the bike parts that I wanted to use. The design process allowed me to achieve quite accurate PCD variations - ie - the mounting disc for the drive needed a PCD bolt pattern to match the chainring and then another to mount to the pattern on the go-kart hub.

Here's a couple of shots of testing variations in the chain rings and spacer set up.

 I also used extra multiples of the same disc to make a basic brake for the wheel.  It doesn't really need a brake but I thought it would make a reassuring safety component.

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