It’s not only about the wheel
Besides the big part to build of the wheel, the problem is also the extension of the project, I have to find a way to connect the wheel to a gear of some sort in order to convert the kinetic energy into electric energy.
I looked into it and probably the easier way is to use a bicycle dynamo to generate energy since the option of a power generator is simply exclude, one of my coursemates indeed showed me this video which made things clear.
In this regards, I’ve been suggested by my two faithful engineer consultants (David, my university tutor and my brother) to use a bicycle wheel, which if put in contact with the other wheel will simply rotate and generate energy when connected to a dynamo. This seems pretty easy, but will it really work? First thing I need to find a child bicycle wheel, a smaller wheel would be better as it will turn more times and therefore generate more energy than a bigger wheel, so the purpose is to find a 12″ wheel and then obviously a support for it. I found out that this sort of supports are called truing stand, but are quite expensive, might be cheaper to buy a whole second-hand kids bike and chop it with a hacksaw.
Regarding the dynamo, instead I found two options either buy a dynamo and then an adaptor from bike dynamo to usb/phone charger or a slightly more expensive system which does all the work, being a dynamo already connected to a phone charger. I might opt for the second option as I would me more likely to work without troubles.
Furthermore, I intend to create an interface, which will show in real time how much energy the user is producing and how many calories he’s burning. In addiction, the user after using it will be able to enter his name and see his performance place in a leaderboard with all the other users who tried before him.
To realise this interface I obviously have to calculate the speed of the wheel expressed in RPM (Rotation Per Minutes) and the final number of rotations. To calculate this, a Reed Switch connected to an Arduino should be enough.
Then I will have to make a proportion between: RPM, number of rotations, energy produced and calories burned. I might ask the engineers for this, math has never been my strong suit.
Finally, I am planning to create the interface which will show a wheel spinning and the data increasing as the person will be running, here is a very first sketch.
To realise that I intend to use Processing, I have very little experience with that so it will be particularly challenging, however I always liked to do a project with it and this is finally an occasion.