If you’re not satisfied with the lightweight digital speedometer that you can buy at your local bike shop, why not build your own bicycle dashboard using various electrical components and wood? DJ decided to do just that, and gives instructions with an electrical schematic, parts list, and Arduino sketch, in this Instructables post.
Besides the case, all the components are off-the-shelf, including an Arduino processor, and an impressive 8 “D” batteries that allow it to run for 12 or more hours. The box is laser-cut using the vector file included in the Instrucables post using .2 inch plywood. One could probably find a substitute method or material if this tool isn’t available.
The dashboard runs all of the lights via the Arduino using MOSFET transistors, correlating the dashboard lights to the speed of the wheels. Check out the video below to see this dashboard in use.
Being an occasionally too-timid mountain biker myself, I’ve often thought that it would be very useful to have a simpler version of this dashboard when approaching a jump. Depending on your speed, a green light could mean that you will clear a certain gap, while a red light would mean it’s time to start braking. Calibrating the system could prove painful, so be sure to get your wheel diameter measured correctly!