Here is what I learned about gear ratios. Really the only gears that matter are the ones that connect directly to the energy source or the output. All the other gears just transfer gears and really do not matter that much. Gears can be geared for speed or for torque. If your input gear is small and your output gear is small your torque will be great. If your input gear is small and your output gear is large your torque will be low but your speed will be high.
I learned a bit about creating an electrical charge. In the early stages of creating the cell phone charger, I wanted to see how much electricity I could create by self-powering a motor with my hand. With some help, I was able to connect a volt meter to the electrical output of an engine. I then cranked the engine with my hand. I was only able to create a .033 volt charge, which is very low. I did feel that I would be able to create more voltage by pedeling a bike than just turning a crank with my fingers.
I also learned that the only real electrical part of a USB port are the outside pins. There are 4 pins and the two inside pins are for grounds. I did not worry about the grounds since the electrical charge I was creating was not harmful. With the help of a friend, Elias, the female end of a USB port was sodered to the output wires from the engine.
The last thing I learned was the idea of over engineering. When I was young and I would get scared my father, who is a chemical engineer, would always tell me that I do not have anything to worry about because things (air planes, roller coasters or bridges etc...) are over engineered. I remember being a young child and getting on a plane. I was affraid but my father told me that I had nothing to worry about because engineers had designed the plane 300 times stronger than it had to be. Basically, whatever mother nature or human error, to a certain extent, “threw at the plane” the machine could handle it. I finally learned what this meant. When creating the cell phone charger I realized that I could create something better and in the long runs save myself time by over engineering. Basically where I could put one support I put two. Where I could put one stopper I put two. Where I could put three braces I put four. This made my charger virtually indistructable, which is a good thing because the vibration of the bike caused problems.
I do want to take my cell phone charger a step further. I want to make the charger out of an old VCR or outdated computer or other recycled materials. I think it is great for the environment to make energy from human powered devices made from recycled materials. As of last week, I purchased a $.99 electric can opener from Goodwill and am slowly turning my learning from Constructing Modern Knowledge into a real product prototype that I can use on my bike.