BICYCLE CELL PHONE CHARGER Senior Design Project Team: Ajeetesh Govrineni (EE), Kellen Warriner (IE), Chris Battaglia (ME) Guide: John Kaemmerlen Customer: Sarah Brownell Problem: Cell phones are common in underdeveloped countries such as Haiti, but people lack the means to charge them. Solution: Create a cheap, locally manufactured device capable of charging a cell phone while riding any common bicycle. Design Constraints: Material cost <$15 Manufactured on location, no heavy machinery in construction (lathes, mills, etc) Simple to build and use Durable Must work on most bicycles and phone models (Nokia, Blackberry) Previous Design This is the second iteration of this project. The previous design charged the phone by running a DC generator along the bicycle wheel. Previous team developed a functional prototype, but it was too expensive, difficult to manufacture, did not perform well, and was not aesthetically pleasing Our task was to revaluate the design and make any necessary improvements We ultimately settled on a similar design, albeit more functional, cheaper, and optimized Raw stock materials Machined & Ready for Assembly Finished Device MANUFACTURING All components are designed to be constructed from wholesale purchased components and bulk stock materials (metal, rubber, PVC). Completely assembled using only hand/power tools. Final Results Cost: ~$13 Charge: Half charge Nokia phone in 25 minutes (max speed) Vibrations: Does not misalign after an hour on rough road conditions Note: 400 mA is comparable to a USB socket (e.g. a computer) Concept Selection and Design We decided to keep the wheel-driven design, as it was simple and effective. Generator is based on a DC motor. DC motors are cheaper, simpler, and more resilient than AC motors. However, this necessitates a more complex electrical setup in order to transform the current flow. The cylindrical design of the generator housing allows for minimal labor during construction, and provides a sleek aesthetic, but makes holding the generator to the bicycle frame a problem. This was solved by using two rubber-lined metal clamps, one around the generator and the other the bike frame, connected by a bolt. The friction of the rubber holds the assembly in place and the rotational/hinged design allows for several degrees of movement for positioning against the bike wheel. The phone holder is made from less than a square foot of flat stock material (we used plexiglass acrylic) and one 8” rod. The electrical breadboard is glued to the inside of the lid and can be directly connected to the phone held within. The holder itself is attached directly to the bicycle handlebars via two Velcro zip strips. The elasticity of the metal clamps compensates for any wobble in the wheel. However the rubber nub on the shaft must be firmly pressed against the rubber tire with its surface flush/tangent to the wheel. Positioning the nub at an angle will cause it to slip and drastically reduce the current output. CAD Models Generator attached to bicycle frame Phone holder with breadboard & phone