Build a generator bicycle using an inexpensive and readily available alternator. It is a great way to introduce students to electricity, how it is generated, and how much work it takes to make a small amount of electricity.
How would you or anyone you know like to generate their own electricity? How about generating enough electricity to accomplish a useful task like run a TV or a blender? Picture a party where people make their own frozen drinks. It is something most people never get a chance to try unless they happen to visit a science museum.
This article will walk you through building the generator bicycle shown in Figure 1. We have used the bicycle for two years as a hands on demonstration at the Chicks in Science Expo in Billings Montana, http://www.msubillings.edu/chicks/. It is a great way to introduce students to electricity, how it is generated, and how much work it takes to make a small amount of electricity.
Building a similar project might be of interest to a range of people. Educators will find it useful in providing context to lessons on electricity and the conversion of mechanical to electrical energy. Students will find it an interesting science fair or extra credit project that people are excited to try. Bicycle clubs or organizations sponsoring bicycle trail funding will find it a focal point of meetings and possibly use it to support fund raising activities. People interested in minimizing environmental impacts will be able to back out power from the grid and reduce CO2 emissions while powering a piece of equipment like a TV or computer while exercising. What a perfect way to earn some TV time by powering the equipment while you exercise.
Building the bicycle will utilize a number of skills including electronics, bicycle maintenance, either wood working or preferably welding, and maybe some metal working depending on the route you choose to progress. The project would be ideal for a general handyman or woman, or a small group who can bring various talents to the problem. Most experimenters will have access to much of the supplies needed to make a similar device, so you should be able to keep costs below $100 with a little ingenuity and a good spare parts bin.