How to Use Adafruit ADXL343 STEMMA QT: Examples, Pinouts, and Specs

The Adafruit ADXL343 STEMMA QT (Part ID: 4097) is a compact, low-power 3-axis accelerometer designed for motion sensing and orientation detection. It features an I2C interface for easy integration into microcontroller-based projects and is equipped with the STEMMA QT connector system, enabling plug-and-play functionality. This accelerometer is ideal for applications such as tilt sensing, vibration monitoring, and gesture recognition in robotics, wearables, and IoT devices.

The ADXL343 accelerometer offers a wide range of features and capabilities, making it suitable for various applications. Below are the key technical details:

The ADXL343 STEMMA QT board has the following pinout:

The Adafruit ADXL343 STEMMA QT is straightforward to use in a circuit. Below are the steps and best practices for integrating it into your project:

1. Wiring: Use the STEMMA QT connectors for a quick and reliable connection. Alternatively, you can use jumper wires:

   • Connect VIN to the Arduino's 5V pin.
   • Connect GND to the Arduino's GND pin.
   • Connect SCL to the Arduino's A5 pin (I2C clock line).
   • Connect SDA to the Arduino's A4 pin (I2C data line).

2. Install Libraries: Download and install the Adafruit ADXL343 library and the Adafruit Unified Sensor library from the Arduino Library Manager.

3. Upload Example Code: Use the following example code to read acceleration data:

#include <Wire.h>
#include <Adafruit_Sensor.h>
#include <Adafruit_ADXL343.h>

// Create an ADXL343 object
Adafruit_ADXL343 accel = Adafruit_ADXL343(12345); // Pass an arbitrary sensor ID

void setup() {
  Serial.begin(9600);
  while (!Serial) {
    delay(10); // Wait for Serial Monitor to open
  }

  Serial.println("Adafruit ADXL343 Test");

  // Initialize the sensor
  if (!accel.begin()) {
    Serial.println("Failed to find ADXL343 chip");
    while (1) {
      delay(10); // Halt if sensor is not found
    }
  }
  Serial.println("ADXL343 Found!");

  // Set range to ±2g
  accel.setRange(ADXL343_RANGE_2_G);
  Serial.print("Range set to: ");
  Serial.println(accel.getRange());
}

void loop() {
  // Read acceleration data
  sensors_event_t event;
  accel.getEvent(&event);

  // Print acceleration values
  Serial.print("X: ");
  Serial.print(event.acceleration.x);
  Serial.print(" m/s^2, Y: ");
  Serial.print(event.acceleration.y);
  Serial.print(" m/s^2, Z: ");
  Serial.print(event.acceleration.z);
  Serial.println(" m/s^2");

  delay(500); // Delay for readability
}

• Power Supply: Ensure the board is powered within the specified voltage range (3.3V to 5V).
• I2C Address: The default I2C address is 0x53. If you have multiple devices on the same I2C bus, ensure there are no address conflicts.
• Mounting Orientation: The sensor's orientation affects the acceleration readings. Mount it securely to avoid vibrations or misalignment.

1. Sensor Not Detected:

   • Ensure the wiring is correct and secure.
   • Verify that the I2C address matches the default (0x53) or the configured address.
   • Check if the Adafruit ADXL343 library is installed correctly.

2. Incorrect or No Data:

   • Confirm that the sensor is powered within the specified voltage range.
   • Ensure the sensor is not exposed to excessive vibrations or shocks.

3. Arduino Code Compilation Errors:

   • Verify that all required libraries are installed.
   • Ensure the library versions are compatible with your Arduino IDE.

Q: Can I use the ADXL343 with a 3.3V microcontroller?
A: Yes, the ADXL343 supports both 3.3V and 5V logic levels, making it compatible with a wide range of microcontrollers.

Q: How do I change the measurement range?
A: Use the setRange() function in the Adafruit ADXL343 library. For example, accel.setRange(ADXL343_RANGE_4_G); sets the range to ±4g.

Q: Can I use SPI instead of I2C?
A: Yes, the ADXL343 supports SPI communication. However, the STEMMA QT connectors are designed for I2C. For SPI, you will need to manually wire the SPI pins.

Q: What is the maximum cable length for the STEMMA QT connectors?
A: The maximum cable length depends on the I2C bus speed and environment. For standard I2C speeds (100 kHz), a cable length of up to 1 meter is generally reliable.

By following this documentation, you can effectively integrate the Adafruit ADXL343 STEMMA QT into your projects for accurate motion sensing and orientation detection.