Simple Thermometer Using TMP36 and ESP32

• ESP32 Development board - $5
• TMP36 Temperature Sensor - $1.5
• 3 pieces of jumper wires - a few cents
• [OPTIONAL] Breadboard

1. Connect the middle pin of the temperature IC, TMP36, to pin D6 on the ESP32 Development Board.
2. Connect the left pin with the flat edge of the temperature IC facing towards you, to the 3.3V pin on the ESP32 development board
3. Lastly, connect the right pin of the temperature IC to the GND pin on the ESP32 development board.

There are very subtle differences in when coding a temperature sensor on the ESP32 board as opposed to the Arduino. For the ESP32 board, we do not need to multiply the raw sensor reading by the voltage, but simply needs to be normalized by the 2^10 bits.

const int tempPin = 2;     //analog input pin constant<br>

int tempVal;    // temperature sensor raw readings

float volts;    // variable for storing voltage 

float temp;     // actual temperature variable

void setup()
{
  // start the serial port at 9600 baud
  Serial.begin(9600);
}

void loop()
{
 //read the temp sensor and store it in tempVal
 tempVal = analogRead(tempPin);

 volts = tempVal/1023.0;             // normalize by the maximum temperature raw reading range

 temp = (volts - 0.5) * 100 ;         //calculate temperature celsius from voltage as per the equation found on the sensor spec sheet.

Serial.print(" Temperature is:   "); // print out the following string to the serial monitor
Serial.print(temp);                  // in the same line print the temperature
Serial.println (" degrees C");       // still in the same line print degrees C, then go to next line.

delay(1000);                         // wait for 1 second or 1000 milliseconds before taking the next reading. 
}

Attachments

• lesson_4-tempsensor.ino
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