Temperature Sensor

Learn to use a TMP36 temperature sensor with the Arduino

Written By: Cherie Tan

Difficulty

Easy

Steps

Temperature-sensing is a vital part of many Arduino projects.

This guide will show you how to use the TMP36 temperature sensor with a 100% compatible Arduino development board, the Little Bird Uno R3 board to read the surrounding temperature.

With temperature detection, you could create a solar-powered temperature sensor, a biofeedback device that uses body temperature data, or even a smart coaster that lets you know when your coffee or tea is safe to drink!

Step 1 A Word of Warning!

The TMP36 is a polarised part. The orientation of the TMP36 matters.

If you don't hook it up correctly, it can get very very hot!

In our examples, the flat edge (the bit with the writing) is pointed away from the Arduino.

Step 2 Insert the TMP36 Into the Breadboard

Insert the TMP36 Temperature Sensor into the breadboard so that the flat face of the sensor is facing away from the Arduino.

Step 3 Power supply

Connect the 5V line from the Arduino to the 5V pin of the TMP36.

Step 4 Voltage out pin

Connect Analogue Pin 0 to the TMP36's Voltage Out Pin (this is the middle pin).

Step 5 Ground pin

Connect the TMP36's ground pin to ground on the Arduino.

Step 6 Upload the TMP36 Code to Your Arduino

// We'll use analog input 0 to measure the temperature sensor's
// signal pin.

const int temperaturePin = A0;

void setup() {

  Serial.begin(9600); //Initialize serial port & set baud rate to 9600 bits per second (bps)
}

void loop() {

  float voltage, degreesC, degreesF; //Declare 3 floating point variables

  voltage = getVoltage(temperaturePin); //Measure the voltage at the analog pin

  degreesC = (voltage - 0.5) * 100.0; // Convert the voltage to degrees Celsius

  degreesF = degreesC * (9.0 / 5.0) + 32.0; //Convert degrees Celsius to Fahrenheit

  //Now print to the Serial monitor. Remember the baud must be 9600 on your monitor!
  // These statements will print lines of data like this:
  // "voltage: 0.73 deg C: 22.75 deg F: 72.96"

  Serial.print("voltage: ");
  Serial.print(voltage);
  Serial.print("  deg C: ");
  Serial.print(degreesC);
  Serial.print("  deg F: ");
  Serial.println(degreesF);

  delay(1000); // repeat once per second (change as you wish!)
}

float getVoltage(int pin) //Function to read and return
  //floating-point value (true voltage)
  //on analog pin
  {

    return (analogRead(pin) * 0.004882814);
    // This equation converts the 0 to 1023 value that analogRead()
    // returns, into a 0.0 to 5.0 value that is the true voltage
    // being read at that pin.
  }

// Other things to try with this code:

//   Turn on an LED if the temperature is above or below a value.

//   Read that threshold value from a potentiometer - now you've
//   created a thermostat!

Copy this code and upload it to your Arduino using the Arduino IDE.

View the temperature readings by opening the Serial monitor in your Arduino IDE.