Published December 31, 2015 © GPL3+

Portable Noncontact Tachometer

We use tachometer in our industry. So I'd like to make some tachometer to check it in home with available resource.

IntermediateFull instructions provided1,184

Things used in this project

Hardware components

Serial 16X2 LCD Display

Pcb Push Button

IR Diode and Receiver

270 ohms Resistor

33K Resistor

Multi-Turn Precision Potentiometer- 1k ohms (25 Turn)

Double Sided Tape

Hand tools and fabrication machines

Soldering iron (generic)

Story

We use tachometer in our industry. So Like to make some tachometer to check it in home with available resource.

Step 1: Materails Required

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1) Linkit one Board with Battery.

2) Infra red LED and Photo Diode - 1no.

3) 16X2 Serial LCD display.

4) 270 ohms Resister - 1No.

5) 33K Resister - 1No.

6) 1K Trim pot.

7) PCB puch button 1 No

8) Double Side Tape.

9) Wires, Soldering Iron lead and Paste

10) old Sketch pen.

Step 2: Sensor Circuit

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1) see sensor Circuit Diagram in diagram tag.

2) Cut a small piece of PCB and Soldered the Components as Per diagram.

3) Cut the Sketch Pen body for two smalls tubes.

4) use it to separate the IR LED and Photo Diode.

5) Fix it using Hot Glue Gun.

6) Another Small Circuit For Digital Input using a Push Button and 220 Ohms Resister.

7) Solder a Female PCB connector in the Sensor board.

8) Solder a Male PCB connector in the Switch Board.

9) Solder four wires VCC, GND, Sensor Signal, Push Button Wire in the Sensor PCB.

10) Join the Male connector to Sensor Board Female Connector.

Step 3: Make a Shield

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1) Plug in male connector to the Link it one (to required pins only, For my future use i solder all pins).

2) Join Plain PCB Over it.

3) Solder the pins.

4) Solder the sensor pin wires as follows

a ) Black - GND

b) Red - VCC 5V

c) Blue - A0 Analog input

d) Yellow - 12 Digital Input

5) Solder the Serial LCD Display

a) Black - GND

b) Brown - VCC 5V

c) Red - 1 Tx of the Serial1.

6) Connect the Battery.

All done in circuit part

Step 4: Make it Portable

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Using double Side Sticker Paste the Battery below the Linkit one board. Paste LCD above the PCB over Linkit one Board. Now u have indicator and a sensor probe.

Step 5: Programming

1) Upload the above program to Link it one.

2) Check the sensor reading when different type of object cross.

3) Use 10K trim pot to change the sensitivity.

4) Test with reflecting sticker for tachometer. I check with double side tape with out remove the top paper.

5) It shows more reflection then all other.

6) With that reading Change the if condition value in the Program if required.

7) I use Serial LCd display brought from Robokits india online website. They supply documents for code.

Download Code from coding tab

Step 6: Testing

caption (optional)

Testing video Shows how it shows the reading. Switch on the Link it one board using the battery switch. Press the Push button over the sensor board. Move the Sticker before the Sensor. It shows current RPM. For every 5 crossing it calculate the RPM and shows. When the push button is release it shows the Maximum RPM.

Step 7: Real Time Check

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I check it with my Ceiling fan. Switch off the fan. Paste a piece of double side tape over on the Fan (in industry u use reflection sticker for tachometer). After turn on the fan. Hold the sensor board straight to that sticker and Push the button. U able to see the RPM. After release the push button we able to see Maximum RPM of fan. Use it with any rotating motors.

Code

Tachometer.ino

const int buttonPin = 12;     // the number of the pushbutton pin
const int ledPin =  13;      // the number of the LED pin
int rpmcnt=0;
int sensorstatus=0;
int Buttonstatus=0;

long previoustakentime;
long rpm;
long maxrpm;
String Display2; 

void setup() {
  Serial1.begin(9600);
//  attachInterrupt(0, Count, RISING);
  pinMode(ledPin, OUTPUT);
  pinMode(buttonPin, INPUT);  
  Buttonstatus=0;
  Serial1.write(22);
  Serial1.write(12);
}

void lcddisplay(){
    Serial1.write(128);
    Serial1.println("***Tachometer***");    
    Serial1.write(148);    
    if(digitalRead(buttonPin) == HIGH){
      Display2="RPM : ";
      Display2=Display2 + rpm;
      Display2=Display2 + "          ";
    }
    else
    {
      Display2="MAX RPM :";
      Display2=Display2 + maxrpm;    
      Display2=Display2 + "       ";      
    }
    Serial1.println(Display2);
}

void loop() {
  int sensorValue = analogRead(A0);
  if(digitalRead(buttonPin) == HIGH){
    if (Buttonstatus==0)
    {
      maxrpm=0;
      Buttonstatus=1;
      rpmcnt=0;
      previoustakentime=millis();
    }
    digitalWrite(ledPin, HIGH);  
    if(sensorValue>200 && sensorstatus==0)
    {
      sensorstatus=1;
      rpmcnt=rpmcnt+1;
    }
    else if(sensorValue<200 && sensorstatus==1) 
    {
      sensorstatus=0;
    }     

    if (rpmcnt >= 5)
    {
      rpm = (60000/(millis() - previoustakentime))*rpmcnt;
      if (rpm>maxrpm)
      {
        maxrpm=rpm;
      }
      lcddisplay();
      rpmcnt=0;
      previoustakentime=millis();
    }
  }
  else{
    rpm = 0;
    lcddisplay();
    digitalWrite(ledPin, LOW);
  }
}

Credits

jegatheesan

18 projects • 67 followers

Simply A Mechatronics Lover.

Portable Noncontact Tachometer

Things used in this project

Hardware components

Hand tools and fabrication machines

Story

Step 1: Materails Required

Step 2: Sensor Circuit

Step 3: Make a Shield

Step 4: Make it Portable

Step 5: Programming

Step 6: Testing

Step 7: Real Time Check

Schematics

IR Sensor circuit

Code

Tachometer.ino

Credits

jegatheesan

Comments

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Portable Noncontact Tachometer

Portable Noncontact Tachometer

Things used in this project

Hardware components

Hand tools and fabrication machines

Story

Step 1: Materails Required

Step 2: Sensor Circuit

Step 3: Make a Shield

Step 4: Make it Portable

Step 5: Programming

Step 6: Testing

Step 7: Real Time Check

Schematics

IR Sensor circuit

Code

Tachometer.ino

Credits

jegatheesan

Comments

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