How to Use 16304-SparkFun_Qwiic_TMP102_Digital_Temp_Sensor: Examples, Pinouts, and Specs

The 16304-SparkFun Qwiic TMP102 Digital Temp Sensor is a high-precision digital temperature sensor designed for easy integration into projects and products. Utilizing the TMP102 sensor chip, this breakout board is ideal for environmental temperature sensing for home automation, industrial systems, and weather stations. Its Qwiic connector system enables quick, solderless connection to other Qwiic-compatible devices, making it a convenient choice for rapid prototyping and educational purposes.

• Environmental monitoring
• Data logging
• HVAC systems
• Consumer electronics
• Wearable devices

• Temperature Range: -40°C to +125°C
• Accuracy: ±0.5°C (from -25°C to +85°C)
• Resolution: 0.0625°C
• Supply Voltage: 1.4V to 3.6V
• Interface: I2C
• I2C Address: 0x48 (default), 0x49, 0x4A, 0x4B (with jumpers)

1. Powering the Sensor: Connect the VCC pin to a power supply within the range of 1.4V to 3.6V and the GND pin to the ground of your system.
2. I2C Communication: Connect the SDA and SCL pins to your microcontroller's I2C data and clock lines, respectively.
3. Address Selection: If multiple TMP102 sensors are used on the same I2C bus, configure the ADD0 pin to set different addresses.
4. Alert Functionality: The ALRT pin can be used as an interrupt or comparator output for temperature threshold events.

• Ensure that the power supply is within the specified voltage range to prevent damage.
• Use pull-up resistors on the I2C lines if they are not already present on your microcontroller board.
• Avoid placing the sensor near heat-generating components to ensure accurate readings.
• For optimal performance, calibrate the sensor in the final application environment.

#include <Wire.h>

// TMP102 I2C address is 0x48 (default)
#define Addr 0x48

void setup() {
  // Initialise I2C communication as MASTER
  Wire.begin();
  // Initialise serial communication, set baud rate = 9600
  Serial.begin(9600);
  
  // Start I2C Transmission
  Wire.beginTransmission(Addr);
  // Select configuration register
  Wire.write(0x01);
  // Set continuous conversion mode, 12-bit resolution
  Wire.write(0x60);
  // Stop I2C Transmission
  Wire.endTransmission();
  delay(300);
}

void loop() {
  unsigned int data[2];

  // Start I2C Transmission
  Wire.beginTransmission(Addr);
  // Select data register
  Wire.write(0x00);
  // Stop I2C Transmission
  Wire.endTransmission();

  // Request 2 bytes of data
  Wire.requestFrom(Addr, 2);

  // Read 2 bytes of data
  // temp msb, temp lsb
  if (Wire.available() == 2) {
    data[0] = Wire.read();
    data[1] = Wire.read();
  }

  // Convert the data to 12-bits
  int temp = ((data[0] * 256) + (data[1] & 0xF0)) / 16;
  if (temp > 2047) {
    temp -= 4096;
  }
  float celsius = temp * 0.0625;
  float fahrenheit = (celsius * 1.8) + 32;

  // Output data to serial monitor
  Serial.print("Temperature in Celsius: ");
  Serial.print(celsius);
  Serial.println(" C");
  Serial.print("Temperature in Fahrenheit: ");
  Serial.print(fahrenheit);
  Serial.println(" F");

  delay(500);
}

• Inaccurate Temperature Readings: Ensure the sensor is not placed near heat sources and that it has been properly calibrated.
• No Data on I2C: Check connections and ensure pull-up resistors are in place. Verify that the correct I2C address is being used.

• Sensor Not Responding: Double-check wiring, especially the VCC and GND connections. Ensure that the microcontroller's power supply is stable.
• Multiple Sensors on I2C: Use different addresses for each sensor by configuring the ADD0 pin and ensure no address conflict occurs.

Q: Can the sensor be used with a 5V system? A: While the sensor operates at 1.4V to 3.6V, level shifters can be used for interfacing with a 5V system.

Q: How can I change the I2C address of the sensor? A: The I2C address can be changed by connecting the ADD0 pin to GND, VCC, SDA, or SCL, corresponding to addresses 0x48, 0x49, 0x4A, or 0x4B, respectively.

Q: What is the maximum distance for the I2C bus? A: I2C is typically used for short distances, but with proper bus buffering and termination, longer distances can be achieved. Keep the lines as short as possible for reliable communication.