This project allows you to monitor your bike riding speed and display it on LCD 16×2 mounted on handlebars. The project is built based on Arduino. It uses a magnetic switch/reed switch to measure the speed of one of the bike’s wheels. This simple speedometer should work with any kind of bike/wheel, just simply enter the radius of the wheel in the firmware to calibrate the device for your setup. This project uses 9V battery for power source.
If you want more advance speedometer, you can add a GPS and logging capability. Thus, you could see how fast you’re going and where. With that data you could start predicting how long it would take you based on what time you’re leaving and we’re you’re going.