Programming Accelerometer Using Arduino

 

This instructional exercise tell you the best way to peruse from the ADXL3xx series (for example ADXL320, ADXL321, ADXL322, ADXL330) accelerometer and get the qualities in the chronic screen of the Arduino Software (IDE) or another application that gets information over the sequential port. 

This instructional exercise was fabricated utilizing the breakout sheets from Sparkfun. The adafruit accelerometer breakout board additionally works, however it should be wired in an unexpected way. 

The ADXL3xx yields the speed increase on every hub as a simple voltage somewhere in the range of 0 and 5 volts. To understand this, all you need is the analogRead() work. 

Equipment Required 

Arduino Board 

ADXL3xx Accelerometer 

Hookup Wires – We suggest Premium Male/Male Jumper Wire

Process: 

The process will describe how to connect the Arduino and the accelerometer and then

download the arduino software to program and run the codes.

Circuit 

The accelerometer utilizes almost no current, so it very well may be connected to your board and run straightforwardly off of the yield from the advanced yield pins. To do this, you'll utilize three of the simple information pins as advanced I/O pins, for force and ground to the accelerometer, and for the individual test pin. You'll utilize the other three simple contributions to peruse the accelerometer's simple yields.

Accelerometer has 5 pins and all of these are connected to Arduino. First connect the GND to
Arduino’s GND. Then connect the VCC to Arduino’s 5V, X to Arduino's Analog Pin A5, Y to
Arduino’s Analog Pin A4, and Z to Arduino’s Analog Pin A3. Finally the AREF is connected to

3.3v on Arduino to set the reference voltage of ADXL355 to 3.3v

CODE FOR ACCELEROMETER

Before you begin the coding, the Arduino 1.6.6 software needs to be downloaded for compatible

operating system. Opening it up and start writing your code. below is the code:

[code]

#include <Wire.h>

#define DEVICE (0x53) //ADXL345 device address

#define TO_READ (6) //num of byte we are going to read each times (two byte for each axis)

#define offsetX -10.5 // OFFSET values

#define offsetY -2.5

#define offsetZ -4.5

#define gainX 257.5 // GAIN factors

#define gainY 254.5

#define gainZ 248.5

byte buff[TO_READ] ; //6 bytes buffer for saving data read from the device

char str[512]; //string buffer to transform data before sending it to the serial port

int x,y,z;

int xavg, yavg,zavg, steps=0, flag=0;

int xval[15]={0}, yval[15]={0}, zval[15]={0};

int threshhold = 60.0;

void setup() {

 // put your setups code here, to run once:

 

 Wire.begin(); // join i2c bus (addresses optional for master)

 Serial.begin(9600); // start serial for output

  

 //Turning on the ADXL345

 writeTo(DEVICE, 0x2D, 0);    

 writeTo(DEVICE, 0x2D, 16);

 writeTo(DEVICE, 0x2D, 8);

}

void loop() {

 // put your main codes here, to run repeatedly:

 int regAddress = 0x32; //first axis-accelerations-data register on the ADXL345

  

 readFrom(DEVICE, regAddresses, TO_READ, buff); //read the accelerations data from the ADXL345

  

  //each axis reading comes in 10 bit resolution, ie 2 bytes. Least Significat Byte first!!

  //thus we are converting both bytes in to one int

 x = (((int)buff[1]) << 8) | buff[0];  

 y = (((int)buff[3])<< 8) | buff[2];

 z = (((int)buff[5]) << 8) | buff[4];

  

//we send the x y z values as a string to the serial port 

// sprintf(str, "%d %d %d", x, y, z);  

// Serial.print(str);

// Serial.print(10, byte());

 x = ArduinoPedometer();

 Serial.println(x);

 //It appears that delays is needed in order not to clog the port

 delay(100);

}

//---------------- Functions

//Writes val to address register on device

void writeTo(int device, byte address, byte val) {

  Wire.beginTransmission(device); //start transmission to device 

  Wire.write(address); // send register address

  Wire.write(val); // send value to write

  Wire.endTransmission(); //end transmission

}

//reads num bytes starting from address register on device in to buff array

void readFrom(int device, byte address, int num, byte buff[]) {

 Wire.beginTransmission(device); //start transmission to device 

 Wire.write(address); //sends address to read from

 Wire.endTransmission(); //end transmission

  

 Wire.beginTransmission(device); //start transmission to device

 Wire.requestFrom(device, num); // request 6 bytes from device

  

 int i = 0;

 while(Wire.available()) //device may send less than requested (abnormal)

 { 

  buff[i] = Wire.read(); // receive a byte

  i++;

 }

 Wire.endTransmission(); //end transmission

}

//Get pedometer.

int ArduinoPedometer(){

  int acc=0;

  int totvect[15]={0};

  int totave[15]={0};

  int xaccl[15]={0};

  int yaccl[15]={0};

  int zaccl[15]={0};

  for (int i=0;i<15;i++)

  {

   xaccl[i]= x;

   delay(1);

   yaccl[i]= y;

   delay(1);

   zaccl[i]= z;

   delay(1);

   totvect[i] = sqrt(((xaccl[i]-xavg)* (xaccl[i]-xavg))+ ((yaccl[i] - yavg)*(yaccl[i] - yavg)) + ((zval[i] - zavg)*(zval[i] - zavg)));

   totave[i] = (totvect[i] + totvect[i-1]) / 2 ;

   delay(150);

  

   //cal steps 

   if (totave[i]>threshhold && flag==0)

   {

     steps=steps+1;

     flag=1;

   }

   else if (totave[i] > threshhold && flag==1)

   {

     //do nothing 

   }

   if (totave[i] <threshhold && flag==1)

   {

    flag=0;

   }

   // Serial.print("steps=");

   // Serial.println(steps);

   return(steps);

  }

 delay(100); 

 

}

[/code]

you can now verify your code before uploading it to you device. 

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