A cheap speedometer for vehicles made using Arduino Uno and reed switch
| Component | Amount | Utility |
|---|---|---|
| Arduino Uno | x1 | Microcontroller |
| Reed Switch | x1 | Indicator for one complete turn of the vehicle wheel |
| 16x2 LCD Display | x1 | To display the speed data |
| Potentiometer | x1 | To adjust the contrast of the LCD display if the potentiometer is not built into the LCD module |
This wikipedia article gives an in-depth working of the reed switch.