One way to spin the wheel and charge the Pocket Bolt.

The Pocket Bolt started with a concept from physics class: Faraday’s Law states that a changing magnetic field produces electric current. This is how mechanical motion can charge up a phone.

I first built a prototype to get a tangible sense of the device. I thought about using raw materials, such as a magnet placed within a coil of wire. But after doing some research, I found that such a simple device would not produce enough current due to electrical resistance. To charge an iPhone requires 5 watts of power, whereas this configuration would only generate 1.2 watts at best.

Instead of using raw magnets and wires, I decided to create a generator from a motor. From Faraday’s Law, spinning the magnets within a motor would generate electricity. I began testing the voltage and current of various motors to get as close to the necessary 5 watts as possible. Finally, I ended up using a 5V DC motor stripped from an electric pencil sharpener.

Further research led me to discover critical electrical components to make the circuit work. It needed a full-wave voltage rectifier, which would convert negative voltages from spinning the motor in the opposite direction to positive voltage. A voltage regulator would maintain the voltage at 5 volts, bumping up and down as needed. Lastly, a diode would prevent backflow of charge from leaking back to the motor.

With a tight time frame, I decided to use a similar electric board from another portable charger that came with 2000 mAh rechargeable batteries. I wired my motor into the circuit and attached a wheel to the motor using a 3D printout piece. The last thing to do was to put everything together in a comfortable, handheld 3D printed case. The prototype worked, and I received a lot of great feedback from the community at the EXPO.

The Pocket Bolt is a personal, portable device that harnesses the mechanical energy of spinning a wheel and converts it to electrical energy to charge electronics like iPhones. Its dual purpose was to provide charging capabilities in circumstances without easily accessible electricity and to use fidgeting with the wheel as a clean source of energy. Spinning the wheel in either direction charges the internal rechargeable batteries which, at complete capacity, will bring a dead phone to a full charge.