How to Use Adafruit ADXL326: Examples, Pinouts, and Specs

The Adafruit ADXL326 is a small, thin, low-power, triple-axis accelerometer with signal conditioned voltage outputs. It is capable of measuring acceleration up to ±16 g. It is designed to measure the static acceleration of gravity in tilt-sensing applications, as well as dynamic acceleration resulting from motion, shock, or vibration. Common applications include:

• Motion detection (e.g., tap detection, free-fall detection)
• Orientation sensing (e.g., portrait/landscape detection)
• Vibration analysis in industrial applications
• Gaming and pointing devices
• Fitness and health monitoring devices

• Power Supply: 1.8V to 3.6V
• Sensitivity: 57 mV/g at 3.3V (typical)
• Measurement Range: ±16 g
• Bandwidth: Up to 1600 Hz
• Operating Temperature: -40°C to +85°C
• Low Power: 350 µA (typical)

To use the ADXL326 in a circuit:

1. Connect VCC to a power supply between 1.8V and 3.6V.
2. Connect GND to the ground of your system.
3. Connect XOUT, YOUT, and ZOUT to analog inputs on your microcontroller, such as an Arduino UNO.

• Ensure that the power supply is stable and within the specified voltage range.
• Use decoupling capacitors close to the VCC and GND pins to minimize power supply noise.
• Avoid physical stress and overheating during soldering to prevent damage to the sensor.
• Calibrate the sensor in your application to account for any system-level inaccuracies.

// Include the Arduino Wire library for I2C
#include <Wire.h>

// ADXL326 outputs are analog and need to be read using analog pins
const int xPin = A0;
const int yPin = A1;
const int zPin = A2;

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

void loop() {
  // Read the analog values from the accelerometer
  int xValue = analogRead(xPin);
  int yValue = analogRead(yPin);
  int zValue = analogRead(zPin);

  // Convert the analog values to acceleration in g's
  float xG = (xValue - 512) * (16.0 / 1024.0);
  float yG = (yValue - 512) * (16.0 / 1024.0);
  float zG = (zValue - 512) * (16.0 / 1024.0);

  // Print the acceleration values to the serial monitor
  Serial.print("X: ");
  Serial.print(xG);
  Serial.print("g, Y: ");
  Serial.print(yG);
  Serial.print("g, Z: ");
  Serial.print(zG);
  Serial.println("g");

  // Delay before the next reading
  delay(100);
}

• Inaccurate Readings: Ensure that the accelerometer is properly calibrated and that the analog pins are correctly connected.
• No Output: Check the power supply and connections to the VCC and GND pins. Ensure that the board is not damaged.
• Intermittent Signals: Verify that there are no loose connections and that the solder joints are solid.

Q: Can the ADXL326 be used with a 5V system? A: While the ADXL326 is rated for 1.8V to 3.6V, a logic level converter should be used when interfacing with a 5V system.

Q: How can I improve the accuracy of the sensor? A: Calibration is key. Perform a calibration routine at startup and consider implementing a filtering algorithm to smooth out the data.

Q: What is the purpose of the ST pin? A: The ST pin is used for self-testing the sensor. When activated, it can help verify that the sensor is functioning correctly.

Q: How do I interpret the analog output values? A: The output is proportional to the acceleration measured. You'll need to convert the analog readings to g's using the sensitivity factor provided in the technical specifications.

For further assistance, consult the Adafruit ADXL326 datasheet and additional resources provided by Adafruit.