Description:

This is a digital speedometer using Arduino which measures speed and fare. In this, LM393 Speed Sensor is used to detect the speed of a wheel(A wheel with bunch of holes or color mark which can be detected by the speed sensor) attached to the motor. The output can be viewed on an 16×2 LCD Display and everything is controlled using Arduino UNO.

Circuit Diagram:

Components:

SR. NO.	COMPONENT	PINOUT DIAGRAM	BUY
1	Arduino UNO (Other Arduinos can be used too)	Arduino UNO Pinout Diagram⇗
2	LM393 Speed Sensor
3	16×2 LCD Display
4	L298N Motor Driver
5	BO DC Motor with Gear Box
6	A wheel with holes (Check the 3D Model and Steps Section down below)
7	10K Ohm Potentiometer

Steps and Info:

1. Get correct components as given. You can buy online or offline. I buy electronics components mostly from Amazon.

2. Start connecting the components. If you are new to connecting components in an electronic, circuit then use a Breadboard or you can straight up make connections using Jumper wires but it will create problem when there will be two or more connections needed at one pin(for example two or more different sensors 5V connection to Arduino’s 5V pin). But before soldering components on a PCB or printing a PCB for your circuit, better try using breadboard so that any errors and mistakes can be observed on breadboard and not after soldering. Or do connections in your way.

3. Now after building the circuit, download the Arduino IDE from https://www.arduino.cc/ website.

4. If you are new to Arduino IDE software, then watch this video we made specially for beginners about Arduino IDE.

5. If you know Arduino IDE then straight up copy the code we given and paste it into the Arduino IDE sketch.

6. Connect the Arduino to your Computer/device. Select a proper port, proper Arduino type and whatever other settings are. Here it is Arduino UNO. (If you don’t know what this all is then watch our video: ).

7. Compile the code and Upload it.

8. If any error occurs then try to troubleshoot it by finding/copy-pasting it into our Solve Errors page https://electronicsprojects.in/solve-errors/, or you can straight up paste the error on Internet and you know the rest. Also check if there are no spelling/syntax errors in the code. Compile the code again once to check if errors are fixed. I have given proper connections and code but still nothing is perfect.

9. Once code compiles and uploads smoothly, you can start testing the working of your circuit/project.

10. For this project, you will need a wheel with holes. I have given my 3D printable model in the download section. You can use it, edit it if necessary as there are two files: .stl and Google Sketchup file. If you don’t have 3D printer then you can make a wheel out of something like cardboard or plastic. Also the wheel I posted has 12 holes, so I have written 12 somewhere in the code, if your wheel has different number of holes then make sure to add that number in the code.

11. Now once the wheel is ready, attach it to the shaft of the motor and keep the wheel in between those two black sensors of LM393 Speed Sensor.

12. Observe if something pops up on the LCD, if works then cool, otherwise keep reading.

13. Check the connections and code. Also place wheel properly in the sensor. You can talk with me and the community on our discord server as well. Link to socials is given at right side of this page.

14. If your LM298N Motor Driver is not working or Motor is not spinning then attach a 12v battery to LM298N Motor Driver.

Program Code:

/* https://electronicsprojects.in Speedometer using Arduino, LM393 Speed Sensor, L298N Motor Driver and 16x2 LCD Display */

#include <LiquidCrystal.h>
 
int motorIn1 = 12;
int motorIn2 = 11;
int motorEnA = 13;
 
int encoder = 1;
 
volatile unsigned int counter;
int RPM;
 
LiquidCrystal lcd(2,3,4,5,6,7); /* If output not came then try this (7,6,5,4,3,2) */
 
void setup() {
  pinMode(motorIn1, OUTPUT);
  pinMode(motorIn2, OUTPUT);
  pinMode(motorEnA, OUTPUT);
  pinMode(encoder, INPUT);
 
  digitalWrite(encoder, HIGH);
  digitalWrite(motorIn1, HIGH);
  digitalWrite(motorIn2, LOW);
  analogWrite(motorEnA, 100);
 
  attachInterrupt(0,countpulse,RISING);
  lcd.begin(16, 2);
}
 
void countpulse(){
        counter++;
}
 
void loop() {
  static uint32_t previousMillis;
  if (millis() - previousMillis >= 1000) {
            RPM = (counter/12)*60;       /* Here my wheel has 12 holes so counter/12, i have written 12, if you use my wheel model then okay otherwise you can change that 12 and write your own wheel's number of holes */
            counter = 0;
            previousMillis += 1000;
  }
 
  lcd.setCursor(0,0);
  lcd.print("Speed: ");
  lcd.setCursor(7,0);
  lcd.print(RPM);
  lcd.print(" rps");
  delay(1);
}

Download:

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