It is rare to find a car these days without some mechanism for charging a cell phone. After all, phones need charging all the time and we spend a lot of time in our cars. But what if you spend a lot of time on your bike? Five teens from Lynchburg, Virginia decided to build something to charge their phones from pedal power.
This isn’t a new idea, of course. Your alternator is charging your phone in your car, and bikes have had alternators connected to them for lights and other purposes. According to the team, you need to pedal about 4 miles per hour to get enough voltage to charge the phone. You can go faster though, because the circuit has a regulator. We especially liked how they determined the speed versus the voltage using a tachometer and an electric drill. We also liked the 3D printed parts such as the handlebar mount that you could probably repurpose for other things.
Our only thought would be to use a boost/buck converter so that even lower voltages could generate enough voltage to charge the phone. Sure, the current would be less — there’s no free lunch — but at least you could get some charge.
Perhaps the best thing though is contemplating a summer camp like this and watching the enthusiasm of the team in the video below. When’s the last time your face lit up like that when a project started working?
We’ve seen bike chargers like this before that did use a DC voltage and a boost converter. We’ve also seen a bike powered up with solar cells. It would be fun to connect one of these to an exercise bike so you could feel as though your exercise was accomplishing something.