Analog Speedometer Using Arduino and IR Sensor

The Analog Speedometer Using Arduino and IR Sensor project operates by combining optical sensing, digital computation, and electromechanical actuation to measure and display rotational speed. At the core of the system is an Arduino Uno, which coordinates input signals and drives output displays. An IR sensor module is positioned near a rotating target—such as a motor or a specialized speedometer picture printout—to detect passing markers. Each time a marker passes the IR sensor, it generates a pulse signal. The Arduino measures the frequency or time interval between these pulses to calculate the revolutions per minute (RPM). Once the speed is computed, the system outputs the data in two formats. First, the numeric value is sent to a 16x2 LCD display using the LiquidCrystal Library for precise digital readout. Second, an analog visual representation is driven by a 4-wire bipolar stepper motor connected through an L298N stepper motor driver module and managed by the Stepper Library. The Arduino commands the stepper motor to move a physical needle or indicator to a position proportional to the measured speed, mimicking a traditional vehicle dashboard gauge. A 2.2k resistor is incorporated into the circuit configuration as needed for signal conditioning, while a dedicated power supply ensures stable operation for both the logic components and the higher-current motor driver.