Digital Speedometer and Odometer Circuit using PIC Microcontroller

The Digital Speedometer and Odometer Circuit uses a PIC microcontroller as the central processing unit to calculate and display vehicle speed and total distance traveled. The core sensing mechanism relies on a Hall sensor, which detects passing magnetic fields. Typically, a small magnet is mounted to a rotating wheel, and as the wheel turns, the magnet triggers the Hall sensor with each revolution, generating electrical pulses. These pulses are sent to the PIC microcontroller via connecting wires. The microcontroller's internal timer and counter modules measure the frequency of these pulses to calculate speed based on the known circumference of the wheel. Additionally, by continuously accumulating the total number of pulse counts over time, the microcontroller calculates the total distance traveled, functioning as an odometer. The computed metrics—current speed and cumulative distance—are then processed and outputted to an LCD display for real-time viewing. The entire circuit is assembled on a breadboard or perfboard and powered by a steady power supply to ensure reliable operation of both the microcontroller and the logic components. Software written in the PIC MPLAB IDE or an equivalent compiler dictates how the microcontroller interprets the sensor inputs, updates the math algorithms, and refreshes the LCD output.