The development of bicycle generator technology far exceeds the bottle generator in the past few years. The bottle generator often does not produce enough resistance to stall the bicycle. Admittedly, it’s not as attractive as an old-fashioned incandescent lamp, but this wheel driven bicycle computer is a good example of getting energy and data from the rotation of bicycle wheels.
Although there are many commercial computers, [Lucas] is looking for some specific functions. His main goal is to use it at night, which means that the backlight display eliminates the usual coin battery power supply. The hub generator of his bicycle offers an interesting possibility – it not only provides AC power, but also its output frequency is directly proportional to the speed of the bicycle. This enables him to derive speed, distance, speed, motion time and other parameters to display in 1 × 8-character LCD display. Some ingenious circuits are needed to adjust the output of the hub generator. A 1.5 farad supercapacitor can keep the device powered for four days without the bicycle moving.
As for measuring the frequency of the generator output, [Lucas] only needs to use a digital input on the MSP430 microcontroller, and of course, a little signal regulation. He also added a barometer chip for altitude data and an ambient light sensor for controlling LCD backlight. Everything lives in a smart 3D printing case, a minimalist but thoughtful design, dock and dock easy from bike; [Lukas] assured us that a waterproof version of the box was being made.
We appreciate the elegance of this design and the way it uses data embedded in the power supply. Although [Lukas] seems to use commercial generators, we have seen examples of other self-made hub generators before – even providing regenerative braking.