I was part of a small team that worked with the Rickshaw Bank in Assam, India to develop an inexpensive, human-powered lighting system to improve safety and comfort of riding rickshaws at night. The solution had to be weather resistant, detachable, provide a steady beam of light at low speeds, and had to be easily replicated by workers at the Rickshaw Bank.
The final light design utilized a knurled wheel in contact with the rickshaw tire and attached to a small DC motor to power a set of LEDs. Components for the power generation unit were sourced from scrap electronics, and the light is easily detachable from the rickshaw frame.
BENCHMARKING
To determine the best way to generate power, different methods were benchmarked, including a frictionless system where magnets are passed over a coil of wire, and a “rolling contact” system where a roller connected to a generator (i.e. DC motor) is in contact with the tire. The rolling contact method presented a number of advantages: the system was easily detachable, the DC motor provided better reliability and performance, and a speed advantage produced by the large tire interfacing with the small roller increased power generation.
