DIY Digital Tachometer Circuit Working Using Arduino

In this tutorial, I will show you how to make a digital tachometer using Arduino. The IR proximity sensor module consists of an IR transmitter & receiver that can work a digital Tachometer for speed measurement of any rotating object. The digital tachometer is an RPM counter which counts the number of rotations per minute. Here an Arduino based digital tachometer is used with an IR proximity sensor module to detect any rotational object for count rotations. IR rays from the IR transmitter reflect by in front object and back to the IR receiver and then IR Module generates an output that is detected by the Arduino when we press the start button. It counts continuously for a few seconds.

What is Digital Tachometer?

A tachometer (revolution counter, tach, rev-counter, RPM check) is an instrument estimating the rotation speed of a disk or plate, as in an engine or other machine. The gadget generally shows the revolutions per minute (RPM) on an adjusted analogue dial, yet digital tachometer shows are progressively normal.

To know about more of this tachometer then visit this link “Tachometer

Circuit Diagram

digital tachometer using arduino

Components Required

  • Arduino 
  • 16*2 LCD Display
  • IR Proximity Sensor Module
  • DC Fan
  • Breadboard 
  • Jumper Wires

Circuit Connection

LCD display to Arduino Nano setup connection

  • Connect LCD pins 1, 3, 5,16 to the GND pin of Arduino Nano
  • Connect LCD pin 4 to the pin D7 of Arduino Nano
  • Connect LCD pin 6 to pin D6 of Arduino Nano
  • Connect LCD pin 11 to pin D5 of Arduino Nano
  • Connect LCD pin 12 to pin D4 of Arduino Nano
  • Connect LCD pin 13 to pin D3 of Arduino Nano
  • Connect LCD pin 14 to pin D2 of Arduino Nano
  • Connect IR proximity sensor module pin GND to GND pin of Arduino Nano
  • Connect IR proximity sensor module plus pin to VCC pin of Arduino Nano
  • Connect IR proximity sensor module output pin to pin D9 of Arduino Nano 
  • Connect LCD pins 2, 15 to the VCC(+5 V) pin of Arduino Nano

Working of Digital Tachometer

An infrared sensor is an electronic component that is used to detect infrared radiation. An infrared sensor is also capable of measuring the heat of an object that’s why we can measure the temperature of any materials or human beings. 

The infrared transmitter is a light emitting diode that emits infrared radiation. Hence, they are called IR LEDs. This radiation is invisible to the human eye. Infrared receivers are also called as infrared sensors so it detects the radiation from the IR transmitter. Infrared photodiodes are different from normal P-N junction diodes because they detect only infrared radiation. 

In this digital tachometer circuit, the IR proximity sensor module is connected with Arduino to measure rotation speed in RPM. 

After sometime Arduino gives a signal to calculate RPM using the given formula.

RPM=count x 12 / objects

Where object = all fan blades 

Applications This device can use for many types of movement and rotating measurements like motor speed, all types of car speed measurement, and many industrial measurements, etc.

Arduino Code

/*Electro Gadget -*/
#include <LiquidCrystal.h>
LiquidCrystal lcd(7, 6, 5, 4, 3, 2);
#define sensor 9
#define start 12
int delay1()
//unsigned int long k;
int i,j;
unsigned int count=0;
return count;
void setup()
pinMode(sensor, INPUT);
pinMode(start, INPUT);
pinMode(2, OUTPUT);
digitalWrite(start, HIGH);
void loop()
unsigned int time=0,RPM=0;

Leave a comment