3 Axis Digital Accelerometer(ADXL345),Gyroscope

The ADXL345 is a ultralow power, small, thin, 3-axis accelerometer with high resolution(13-bit) measurement at up to ±16 g. it communicate with MCU in I2C or SPI communication type. The ADXL345 is well suited to measure the static acceleration of gravity in tilt-sensing applications, as well as dynamic acceleration resulting from motion or shock. For its high resolution (4 mg/LSB), it’s enable to measure the inclination changes less than 1.0°. Several special sensing functions are provided. Activity and inactivity sensing detect the presence or lack of motion and if the acceleration on any axis exceeds a user-set level. Tap sensing detects single and double taps. Free-fall sensing detects if the device is falling. These functions can be mapped to one of two interrupt output pins.

Technical data

Work voltage: 3 to 5V

Sensitivity:

X: 28.6 LSB/g

Y: 31.2 LSB/g

Z: 34.5LSB/g

Usage

[code]

/*****************************************************************************/

// This library is free software; you can redistribute it and/or

// modify it under the terms of the GNU Lesser General Public

// License as published by the Free Software Foundation; either

// version 2.1 of the License, or (at your option) any later version.

// This library is distributed in the hope that it will be useful,

// but WITHOUT ANY WARRANTY; without even the implied warranty of

// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU

// Lesser General Public License for more details.

// You should have received a copy of the GNU Lesser General Public

// License along with this library; if not, write to the Free Software

// Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA

/*******************************************************************************/

#include <Wire.h>

#include <ADXL345.h>

ADXL345 adxl; //variable adxl is an instance of the ADXL345 library

void setup(){

Serial.begin(9600);

adxl.powerOn();

//set activity/ inactivity thresholds (0-255)

adxl.setActivityThreshold(75); //62.5mg per increment

adxl.setInactivityThreshold(75); //62.5mg per increment

adxl.setTimeInactivity(10); // how many seconds of no activity is inactive?

//look of activity movement on this axes - 1 == on; 0 == off

adxl.setActivityX(1);

adxl.setActivityY(1);

adxl.setActivityZ(1);

//look of inactivity movement on this axes - 1 == on; 0 == off

adxl.setInactivityX(1);

adxl.setInactivityY(1);

adxl.setInactivityZ(1);

//look of tap movement on this axes - 1 == on; 0 == off

adxl.setTapDetectionOnX(0);

adxl.setTapDetectionOnY(0);

adxl.setTapDetectionOnZ(1);

//set values for what is a tap, and what is a double tap (0-255)

adxl.setTapThreshold(50); //62.5mg per increment

adxl.setTapDuration(15); //625us per increment

adxl.setDoubleTapLatency(80); //1.25ms per increment

adxl.setDoubleTapWindow(200); //1.25ms per increment

//set values for what is considered freefall (0-255)

adxl.setFreeFallThreshold(7); //(5 - 9) recommended - 62.5mg per increment

adxl.setFreeFallDuration(45); //(20 - 70) recommended - 5ms per increment

//setting all interrupts to take place on int pin 1

//I had issues with int pin 2, was unable to reset it

adxl.setInterruptMapping( ADXL345_INT_SINGLE_TAP_BIT, ADXL345_INT1_PIN );

adxl.setInterruptMapping( ADXL345_INT_DOUBLE_TAP_BIT, ADXL345_INT1_PIN );

adxl.setInterruptMapping( ADXL345_INT_FREE_FALL_BIT, ADXL345_INT1_PIN );

adxl.setInterruptMapping( ADXL345_INT_ACTIVITY_BIT, ADXL345_INT1_PIN );

adxl.setInterruptMapping( ADXL345_INT_INACTIVITY_BIT, ADXL345_INT1_PIN );

//register interrupt actions - 1 == on; 0 == off

adxl.setInterrupt( ADXL345_INT_SINGLE_TAP_BIT, 1);

adxl.setInterrupt( ADXL345_INT_DOUBLE_TAP_BIT, 1);

adxl.setInterrupt( ADXL345_INT_FREE_FALL_BIT, 1);

adxl.setInterrupt( ADXL345_INT_ACTIVITY_BIT, 1);

adxl.setInterrupt( ADXL345_INT_INACTIVITY_BIT, 1);

}

void loop(){

//Boring accelerometer stuff

int x,y,z;

adxl.readXYZ(&x, &y, &z); //read the accelerometer values and store them in variables x,y,z

// Output x,y,z values

Serial.print("values of X , Y , Z: ");

Serial.print(x);

Serial.print(" , ");

Serial.print(y);

Serial.print(" , ");

Serial.println(z);

double xyz[3];

double ax,ay,az;

adxl.getAcceleration(xyz);

ax = xyz[0];

ay = xyz[1];

az = xyz[2];

Serial.print("X=");

Serial.print(ax);

Serial.println(" g");

Serial.print("Y=");

Serial.print(ay);

Serial.println(" g");

Serial.print("Z=");

Serial.println(az);

Serial.println(" g");

Serial.println("**********************");

delay(500);

//Fun Stuff!

//read interrupts source and look for triggerd actions

//getInterruptSource clears all triggered actions after returning value

//so do not call again until you need to recheck for triggered actions

byte interrupts = adxl.getInterruptSource();

// freefall

if(adxl.triggered(interrupts, ADXL345_FREE_FALL)){

Serial.println("freefall");

//add code here to do when freefall is sensed

}

//inactivity

if(adxl.triggered(interrupts, ADXL345_INACTIVITY)){

Serial.println("inactivity");

//add code here to do when inactivity is sensed

}

//activity

if(adxl.triggered(interrupts, ADXL345_ACTIVITY)){

Serial.println("activity");

//add code here to do when activity is sensed

}

//double tap

if(adxl.triggered(interrupts, ADXL345_DOUBLE_TAP)){

Serial.println("double tap");

//add code here to do when a 2X tap is sensed

}

//tap

if(adxl.triggered(interrupts, ADXL345_SINGLE_TAP)){

Serial.println("tap");

//add code here to do when a tap is sensed

} */

}

[/code]

Features

Ultra Low Power: 40uA in measurement mode, 0.1uA in standby@ 2.5V.

Tap/Double Tap Detection.

Free-Fall Detection.

SPI and I2C interfaces.

Application

Industrial instrumentation

Medical instrumentation

Hard disk drive(HDD) protection

Resource

Program

Schematic

Datesheet