How to Use Temperature sensor: Examples, Pinouts, and Specs

The TMP36 is a low voltage, precision centigrade temperature sensor manufactured by Analog Devices. It provides a voltage output that is linearly proportional to the Celsius temperature. The TMP36 is easy to use and requires no external calibration or trimming to provide typical accuracies of ±1°C at +25°C and ±2°C over the −40°C to +125°C temperature range.

• Environmental monitoring systems
• Consumer electronics
• Industrial temperature control
• HVAC systems
• Medical devices
• Data loggers

1. Power the Sensor: Connect the Vcc pin to a 2.7V to 5.5V power supply.
2. Ground Connection: Connect the GND pin to the ground of the circuit.
3. Read the Output: Connect the Vout pin to an analog input of a microcontroller or an ADC (Analog-to-Digital Converter).

• Decoupling Capacitor: Place a 0.1 µF capacitor between Vcc and GND close to the sensor to filter out noise.
• Avoid Long Wires: Long wires can introduce noise and affect the accuracy of the sensor. Keep connections short.
• Stable Power Supply: Ensure a stable power supply to avoid fluctuations in the output voltage.
• Thermal Isolation: Avoid placing the sensor near heat sources or in direct sunlight to prevent inaccurate readings.

TMP36 Pin 1 (Vcc)  -> Arduino 5V
TMP36 Pin 2 (Vout) -> Arduino A0
TMP36 Pin 3 (GND)  -> Arduino GND

// TMP36 Temperature Sensor Example Code
// Reads temperature from TMP36 and prints to Serial Monitor

const int sensorPin = A0; // TMP36 connected to analog pin A0
int sensorValue = 0;      // Variable to store the sensor value
float voltage = 0.0;      // Variable to store the voltage
float temperatureC = 0.0; // Variable to store the temperature in Celsius

void setup() {
  Serial.begin(9600); // Initialize serial communication at 9600 bps
}

void loop() {
  sensorValue = analogRead(sensorPin); // Read the analog value from sensor
  voltage = sensorValue * (5.0 / 1023.0); // Convert the analog value to voltage
  temperatureC = (voltage - 0.5) * 100.0; // Convert voltage to temperature
  
  // Print the temperature to the Serial Monitor
  Serial.print("Temperature: ");
  Serial.print(temperatureC);
  Serial.println(" °C");
  
  delay(1000); // Wait for 1 second before next reading
}

1. Inaccurate Readings:

   • Solution: Ensure stable power supply and proper decoupling capacitor. Avoid placing the sensor near heat sources.

2. No Output Voltage:

   • Solution: Check connections and ensure the sensor is powered correctly. Verify the ground connection.

3. Fluctuating Readings:

   • Solution: Use a decoupling capacitor and ensure short, stable connections. Check for electrical noise in the environment.

Q1: Can the TMP36 be used to measure negative temperatures?

• A1: Yes, the TMP36 can measure temperatures as low as -40°C. The output voltage will be below 0.5V for negative temperatures.

Q2: What is the accuracy of the TMP36?

• A2: The TMP36 has an accuracy of ±1°C at +25°C and ±2°C over the full temperature range.

Q3: Can I use the TMP36 with a 3.3V power supply?

• A3: Yes, the TMP36 can operate with a supply voltage as low as 2.7V, making it compatible with 3.3V systems.

Q4: How do I convert the output voltage to temperature?

• A4: The output voltage can be converted to temperature using the formula: Temperature (°C) = (Vout - 0.5) * 100.

By following this documentation, users can effectively integrate the TMP36 temperature sensor into their projects, ensuring accurate and reliable temperature measurements.