How to Use LilyPad Accelerometer: Examples, Pinouts, and Specs

The LilyPad Accelerometer ADXL335 is a small, thin, low-power, complete 3-axis accelerometer with signal-conditioned voltage outputs. It measures acceleration with a minimum full-scale range of ±3 g. It can measure the static acceleration of gravity in tilt-sensing applications, as well as dynamic acceleration resulting from motion or shock. Its high resolution (1 mg/LSB) enables the measurement of inclination changes less than 1.0°.

Common applications of the LilyPad Accelerometer include:

• Wearable devices
• Motion detection
• Gaming and pointing devices
• Fitness and activity monitoring
• Tilt sensing in robotics and vehicles

• Power Supply: 2.0V to 3.6V DC
• Sensitivity: Typically 300 mV/g at 3V
• Measurement Range: ±3 g
• Bandwidth: 50 Hz
• Operating Temperature: -40°C to +85°C
• Self-Test Feature

To use the LilyPad Accelerometer in a circuit:

1. Connect the VCC pin to a power supply between 2.0V and 3.6V.
2. Connect the GND pin to the ground of the power supply.
3. The X-OUT, Y-OUT, and Z-OUT pins provide analog voltage outputs that correspond to the acceleration on each axis. Connect these to analog inputs on your microcontroller, such as an Arduino UNO.

• Ensure that the power supply voltage does not exceed 3.6V.
• Use capacitors for noise reduction if necessary, as specified in the datasheet.
• Avoid physical shock and vibration that exceed the specified limits.
• Keep the device within the specified temperature range to ensure accuracy.

// Include the Arduino core library
#include <Arduino.h>

// Define the analog pins connected to the accelerometer
const int xPin = A0;
const int yPin = A1;
const int zPin = A2;

void setup() {
  // Initialize the serial communication
  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 xAccel = (xValue - 338.0) / 100.0; // 338 is zero-g voltage for x-axis
  float yAccel = (yValue - 338.0) / 100.0; // 338 is zero-g voltage for y-axis
  float zAccel = (zValue - 338.0) / 100.0; // 338 is zero-g voltage for z-axis

  // Print the acceleration values to the serial monitor
  Serial.print("X: ");
  Serial.print(xAccel);
  Serial.print("g, Y: ");
  Serial.print(yAccel);
  Serial.print("g, Z: ");
  Serial.print(zAccel);
  Serial.println("g");

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

Note: The zero-g voltage and sensitivity may vary slightly from one device to another. Calibration may be required for precise measurements.

• Inaccurate Readings: Ensure that the accelerometer is properly calibrated. Check for any power supply issues or interference from other electronic components.
• No Output Signal: Verify that the VCC and GND connections are secure and that the power supply is within the specified range.
• Intermittent Signal: Check for loose connections and ensure that the accelerometer is not subjected to mechanical stress or shock beyond its limits.

Q: Can the LilyPad Accelerometer be washed? A: The LilyPad Accelerometer is designed for use in e-textiles and wearable projects, but it is not waterproof. It should be removed before washing the fabric.

Q: How do I calibrate the accelerometer? A: Calibration involves recording the output at known orientations and adjusting the readings accordingly. Refer to the datasheet for detailed calibration procedures.

Q: What is the purpose of the self-test pin? A: The self-test pin, when set to a logic high, allows you to check the functionality of the accelerometer by producing a known output signal.

For further assistance, consult the manufacturer's datasheet and technical support resources.