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Adafruit ADXL343 Accelerometer

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Important Note

This entire repo was AI created - including all of the data within. The intent was to A) help me with my personal electronics inventory; and B) see how I could use AI to make that process a bit easier. DO NOT TRUST!

Adafruit ADXL343 Accelerometer

High-performance 3-axis accelerometer with advanced motion detection features, low power operation, and flexible interface options for demanding applications.

Overview

The Adafruit ADXL343 is a small, thin, ultralow power, 3-axis accelerometer with high resolution (13-bit) measurement at up to ±16g. This sensor is based on Analog Devices’ ADXL343 and provides advanced motion detection capabilities including activity/inactivity monitoring, tap detection, and free-fall detection.

Key Features

High Performance Sensing

  • 13-bit resolution for precise measurements
  • Multiple measurement ranges (±2g to ±16g)
  • Low noise and high stability
  • Fast data rates up to 3200Hz
  • Advanced motion detection algorithms

Power Efficiency

  • Ultra-low power consumption (25μA in measurement mode)
  • Multiple power modes for different applications
  • Sleep and standby modes for battery conservation
  • Auto-sleep functionality
  • Wake-up on motion capability

Advanced Features

  • Activity/inactivity detection
  • Single/double tap detection
  • Free-fall detection with configurable parameters
  • Orientation sensing (portrait/landscape)
  • Shock detection with programmable thresholds

Technical Specifications

Electrical Characteristics

  • Operating Voltage: 2.0V to 3.6V (3.3V recommended)
  • Supply Current: 25μA (measurement mode), 0.1μA (standby)
  • Interface: I²C (up to 400kHz) or SPI (up to 5MHz)
  • I²C Address: 0x53 (default) or 0x1D (configurable)

Performance Specifications

  • Measurement Range: ±2g, ±4g, ±8g, ±16g (selectable)
  • Resolution: 13-bit (up to 4mg/LSB at ±16g)
  • Output Data Rate: 0.1Hz to 3200Hz
  • Zero-g offset: ±150mg maximum
  • Sensitivity: 256 LSB/g (±2g), 128 LSB/g (±4g), 64 LSB/g (±8g), 32 LSB/g (±16g)

Environmental Specifications

  • Operating Temperature: -40°C to +85°C
  • Shock Survival: 10,000g for 0.2ms
  • Package: 3mm × 5mm × 1mm LGA

Applications

Consumer Electronics

  • Smartphone orientation sensing
  • Gaming controllers with motion input
  • Fitness trackers and activity monitors
  • Camera stabilization systems
  • Portable device auto-sleep functionality

Industrial Applications

  • Machine vibration monitoring
  • Equipment tilt detection
  • Asset tracking with motion sensing
  • Safety systems with shock detection
  • Platform stabilization control

Automotive Applications

  • Vehicle dynamics monitoring
  • Crash detection systems
  • Anti-theft motion sensing
  • Parking assistance with tilt detection
  • Electronic stability control

Programming Example

Arduino Basic Usage

#include <Adafruit_ADXL343.h>
 
Adafruit_ADXL343 accel = Adafruit_ADXL343(12345);
 
void setup() {
  Serial.begin(115200);
  
  if (!accel.begin()) {
    Serial.println("Could not find ADXL343");
    while (1);
  }
  
  // Set range and data rate
  accel.setRange(ADXL343_RANGE_4_G);
  accel.setDataRate(ADXL343_DATARATE_100_HZ);
  
  Serial.println("ADXL343 found!");
}
 
void loop() {
  sensors_event_t event;
  accel.getEvent(&event);
  
  Serial.print("X: "); Serial.print(event.acceleration.x);
  Serial.print(" Y: "); Serial.print(event.acceleration.y);
  Serial.print(" Z: "); Serial.println(event.acceleration.z);
  
  delay(100);
}

Advanced Motion Detection

// Configure tap detection
void setupTapDetection() {
  // Set tap threshold (62.5mg/LSB)
  accel.writeRegister(ADXL343_REG_THRESH_TAP, 50);  // ~3.1g threshold
  
  // Set tap duration (625μs/LSB)
  accel.writeRegister(ADXL343_REG_DUR, 15);  // ~9.4ms duration
  
  // Set tap latency (1.25ms/LSB)
  accel.writeRegister(ADXL343_REG_LATENT, 80);  // ~100ms latency
  
  // Set tap window (1.25ms/LSB)
  accel.writeRegister(ADXL343_REG_WINDOW, 200);  // ~250ms window
  
  // Enable tap detection on all axes
  accel.writeRegister(ADXL343_REG_TAP_AXES, 0x07);
  
  // Enable tap interrupt
  accel.writeRegister(ADXL343_REG_INT_ENABLE, 0x40);
}
 
// Configure free-fall detection
void setupFreeFallDetection() {
  // Set free-fall threshold (62.5mg/LSB)
  accel.writeRegister(ADXL343_REG_THRESH_FF, 7);  // ~437mg threshold
  
  // Set free-fall time (5ms/LSB)
  accel.writeRegister(ADXL343_REG_TIME_FF, 30);  // ~150ms duration
  
  // Enable free-fall interrupt
  accel.writeRegister(ADXL343_REG_INT_ENABLE, 0x04);
}

Pinout and Connections

Standard Connections

PinSignalDescription
VINVCCPower input (2.0V to 5.5V with regulator)
3V33V33.3V regulated output
GNDGNDGround
SCLSCLI²C Clock / SPI Clock
SDASDAI²C Data / SPI MOSI
SDOSDOSPI MISO / I²C Address Select
CSCSSPI Chip Select

Interrupt Pins

PinSignalDescription
INT1INT1Interrupt 1 output
INT2INT2Interrupt 2 output

Power Management

Power Modes

  • Measurement Mode: 25μA at 100Hz data rate
  • Standby Mode: 0.1μA with quick wake-up
  • Sleep Mode: Ultra-low power with wake-up capability
  • Auto-sleep: Automatic transition based on activity

Power Optimization Strategies

// Configure low power mode
void configureLowPower() {
  // Set low power mode
  accel.writeRegister(ADXL343_REG_BW_RATE, 0x10);  // Low power bit set
  
  // Reduce data rate for lower power
  accel.setDataRate(ADXL343_DATARATE_12_5_HZ);
  
  // Enable auto-sleep
  accel.writeRegister(ADXL343_REG_POWER_CTL, 0x18);  // Auto-sleep + measure
  
  // Set activity threshold for wake-up
  accel.writeRegister(ADXL343_REG_THRESH_ACT, 4);  // ~250mg threshold
}

Motion Detection Features

Activity/Inactivity Detection

  • Configurable thresholds for activity detection
  • Time-based validation to prevent false triggers
  • Automatic sleep transition on inactivity
  • Wake-up on activity for power savings
  • Independent X, Y, Z axis enable/disable

Tap Detection

  • Single tap and double tap recognition
  • Configurable thresholds and timing parameters
  • Axis-specific tap detection enable
  • Tap duration and latency settings
  • Window timing for double tap validation

Free-Fall Detection

  • Configurable threshold (typically 300-600mg)
  • Duration validation to confirm free-fall
  • All-axis monitoring for true free-fall detection
  • Interrupt generation on detection
  • Low false-positive rate with proper tuning

Orientation Detection

  • Portrait/landscape detection
  • Face up/face down sensing
  • Configurable deadband for stability
  • Hysteresis to prevent oscillation
  • Interrupt on orientation change

Calibration and Setup

Basic Calibration

  1. Offset calibration: Measure and correct zero-g offsets
  2. Sensitivity verification: Validate against known accelerations
  3. Temperature compensation: Account for temperature effects
  4. Noise characterization: Determine baseline noise levels

Motion Detection Tuning

  1. Threshold optimization: Adjust for application requirements
  2. Duration tuning: Set appropriate validation times
  3. False positive reduction: Optimize parameters for environment
  4. Environmental testing: Validate in real operating conditions

Design Considerations

Mechanical Design

  • Rigid mounting: Minimize vibration and mechanical noise
  • Proper orientation: Align axes with measurement requirements
  • Shock protection: Design for expected shock levels
  • Temperature stability: Account for thermal effects

Electrical Design

  • Power supply filtering: Use clean, stable power source
  • Bypass capacitors: 0.1μF ceramic near power pins
  • I²C pull-ups: 4.7kΩ resistors on SCL/SDA
  • Interrupt handling: Proper interrupt service routines

Software Design

  • Interrupt-driven: Use interrupts for efficient operation
  • Data filtering: Implement appropriate digital filters
  • Calibration storage: Store calibration in non-volatile memory
  • Error handling: Robust error detection and recovery

Troubleshooting

Common Issues

  • High noise: Check power supply, mounting, and filtering
  • False motion detection: Adjust thresholds and validation times
  • Communication errors: Verify I²C/SPI connections and settings
  • Power consumption: Optimize data rates and power modes

Performance Optimization

  • Proper calibration: Follow calibration procedures carefully
  • Environmental control: Minimize vibration and temperature variations
  • Power management: Use appropriate power modes for application
  • Signal processing: Implement effective filtering algorithms

Storage Information

  • Location: Cabinet 3, Bin 28
  • Quantity: 2 units
  • Condition: New, unused
  • Features: High resolution, advanced motion detection, ultra-low power

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