Arduino Mini Speed Meter Using IR Sensor and 16×2 LCD

The objective of this project is to measure the speed of a rotating wheel using an IR sensor and display the calculated speed on a 16×2 LCD.

Deshbot shield

Arduino Nano/Uno

16×2 LCD display

IR sensor module

Connecting wires

The IR sensor is placed near a rotating wheel. A mark or suitable detecting point on the wheel passes in front of the IR sensor once during each revolution.

The Arduino detects the change in the IR sensor output and measures the time between two consecutive detections.

The speed is calculated using:

Speed = Distance ÷ Time

For a rotating wheel, the distance travelled in one revolution is the wheel circumference.

The calculated speed is converted from metres per second to kilometres per hour and displayed on the 16×2 LCD.

Speed Calculation

The program uses the wheel circumference and the time between two IR detections.

For example, if the wheel circumference is 0.20 metres and one revolution takes 0.5 seconds:

Speed = 0.20 ÷ 0.5

Speed = 0.4 m/s

Converting to km/h:

0.4 × 3.6 = 1.44 km/h

LCD Output

The LCD displays the measured speed and the number of detected revolutions.

Example:

Important Setting

The wheel circumference is set in the Arduino code:

The value must be changed according to the actual wheel.

For example:

1. 10 cm circumference → 0.10
2. 20 cm circumference → 0.20
3. 30 cm circumference → 0.30

IR Sensor

IR SensorArduino

VCC - 5V

GND - GND

OUT - D9

16×2 LCD

LCD PinArduino

RS - A4

EN - A3

D4 - A2

D5 - A1

D6- A0

D7 - D13

VSS - GND

VDD - 5V

The Mini Speed Meter demonstrates how an Arduino can detect wheel rotation using an IR sensor, calculate speed using the time between rotations, and display the result on a 16×2 LCD. It is a simple practical project that combines sensors, programming, mathematics, and display technology.