# How to make a Tachometer for bicycle

To make a tachometer for bicycle tachometer we will be using Arduino and reed switch as the main component. We will design the tachometer to Display Speed and also temperature. Following are the list of components required.

Parts list:

• Arduino
• Bicycle with reed switch
• LCD display 16×2
• thermometer DS18B20
• Servo
• resistor 1.2k Ω , 4.7k Ω
• potentiometer 10 kΩ
• Miscellaneous – 9V battery, cables, switch, button
• Enclosure

Note that you can omit the Servo if you do not want to display speed in graphical way.

You may refer my earlier post on how to connect LCD display, measure temperature using DS18b20 sensor and how to control servo using Arduino

How to connect 16*2 LCD display Arduino UNO

How to Measure temperature with Arduino and DS18B20 sensor?

Servo Motor Control using Arduino

Step 1: Connecting the LCD display

• VSS –> GND Arduino
• VDP –> 5V Arduino
• VO –> output potentiometer (potentiometer VCC -> 5V Arduino, potentiometer GND -> Arduino GND).
• RS –> pin 12 Arduino
• RW –> GND Arduino
• E –> pin 11 Arduino
• D4 –> pin 5 Arduino
• D5 –> pin 4 Arduino
• D6 –> pin 3 Arduino
• D7 –> pin 2 Arduino
• A –> 5V Arduino with 1.2 k resistor
• K –> GND Arduino

Step 2: Connecting the Servo

• VCC –> 5V Arduino
• mass –> GND Arduino
• Data –> pin 6 Arduino

Step 3: Connecting the Thermometer

• VCC –> 5V Arduino
• mass –> GND Arduino
• Data –> pin 1 Arduino

data and power is connected via a 4.7 kΩresistor

Step 4: Sensor on wheel (reed switch)

• one end -> 5V Arduino
• second end -> A0 Arduino and resistor 1.2 kΩ

The other end of the resistor to ground in the Arduino

Step 5: Connect the Button

• one end –> 5V Arduino
• second end –> A1 Arduino

If you have a different wheel diameter you have to change it. You can calculate it with this formula:

circuit = π*d*2,54 (d=diameter of your wheel, I multiplied it by 2.54 to get the result in meters).

```//Code
#include  < Servo.h>
#include <LiquidCrystal.h>
#include <OneWire.h>
#include <DallasTemperature.h>

#define ONE_WIRE_BUS 1
OneWire oneWire(ONE_WIRE_BUS);
DallasTemperature sensors(&oneWire);

//LCD display pins
LiquidCrystal lcd(12, 11, 5, 4, 3, 2);
//servo name
Servo myservo;
//definition of variables
long previous, triptime, time, impulses;
float speedometer, dist, aspeed;
int servo;
int screen=1;
//If you have other diameter of wheel you need change it
float circuit=2.0;
double temperature;

void setup() {

lcd.begin(16, 2);
pinMode(A0, INPUT);
pinMode(A1, INPUT);

//servo definition and setting the tachometer to 0
myservo.attach(6);
myservo.write(180);
lcd.print("Bike tachometer");
delay(1000);
lcd.setCursor(5, 1);
lcd.print("V 1.0");
delay(4000);
lcd.clear();
delay(500);
lcd.setCursor(0, 0);
lcd.print("Dist:");
}

void loop() {
//if wheel turns
//number of turns++
impulses++;
//count turn time
time=(millis()-previous);
//count speed
speedometer=(circuit / time)*3600.0;
previous=millis();
Tachometer();
delay(100);
}

Lcd();
}

//display speed on tachometer
void Tachometer(){
//map speed 0-180 to servo
speedometer=int(speedometer);
servo = map(speedometer, 0, 72, 180, 0);
//setup servo
myservo.write(servo);
}

void Lcd(){
//when button is clicked
lcd.clear();
screen++;
if(screen==5){
screen=1;
}
}

if(screen==1){
//displays speed
lcd.setCursor(0, 1);
lcd.print("Speed:");
lcd.setCursor(7, 1);
lcd.print(speedometer);
lcd.print("km/h");
}

if(screen==2){

//displays themperature
temperature=sensors.getTempCByIndex(0);
sensors.requestTemperatures();
lcd.setCursor(0, 1);
lcd.print("Temp:");
lcd.setCursor(7, 1);
lcd.print(temperature);
lcd.print(" C");
}

if(screen==3){
//displays averagr speed
aspeed=dist/(millis()/1000.0)*3600.0;
lcd.setCursor(0, 1);
lcd.print("A.speed:");
lcd.setCursor(8, 1);
lcd.print(aspeed);
lcd.print("km/h");
}

if(screen== 4){
//diplays trip time
triptime=millis()/60000;

lcd.setCursor(0, 1);
lcd.print("Time:");
lcd.setCursor(7, 1);
lcd.print(triptime);

}

lcd.setCursor(0, 0);
lcd.print("Dist:");
//calculation of the distance
dist=impulses*circuit/1000.00;
//dislays distance
lcd.setCursor(6,0);
lcd.print(dist);
lcd.print("km");
}

```

Cut the image below and stick on top of the enclosure. You need to position the servo at the Centre. Movement of the arm will indicate the speed in the tachometer for bicycle. To make it simple you can omit this part and just use the LCD to display the speed and distance only. Temperature display is also optional. May be you can add extra features one by one.

This site uses Akismet to reduce spam. Learn how your comment data is processed.