How to Charge Any USB Device by Riding Your Bike

Step 8 Testing!

For the capacitors, we test two different types, the BOOSTCAP and a super capacitor.

The first graph depicts the use of the supercapacitor, which is integrated with the circuit so that when the motor is active, the capacitor will charge. We did not use this component because, while the supercapacitor charged with extreme speed, it discharged too quickly for our purposes. The red line represents the voltage of the motor, the blue line represents the voltage of the supercapacitor, and the green line represents voltage of the USB port.

The second graph is the data collected with the BOOSTCAP ultracapacitor. The red line represents the motor's voltage, the blue is the ultracapacitor's voltage, and the green line represents the USB port's voltage. We chose to use the ultracapacitor because, as this test indicates, the ultracapacitor will continue to hold its charge even after the rider has stopped moving. The reason for the jump in USB voltage is because the ultracapacitor reached the voltage threshold necessary to activate the MintyBoost.

Both of these tests were conducted over a period of 10 minutes. The rider pedaled for the first 5, then we observed how the voltages would react for the final 5 minutes.


The last picture is a Google Earth shot of where we did our testing. This picture shows that we started at our school, and then did two laps at Levagood Park for a total approximate distance of 1 mile. The colors of this map correspond to the speed of the rider. The purple line is approximately 28.9 mph, the blue line 21.7 mph, the green line 14.5 mph, and the yellow line 7.4 mph.