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Topic: Triple Axis Accelerometer Breakout - ADXL345 (Read 2655 times) previous topic - next topic

fraser_s

I have managed to get the arduino to recognise the accelerometer but I cant work out the if/else code so that it recognises different movements.

any help would be awesome!!

AWOL

You'll need to post your code for us to see the if/else you're referring to.
"Pete, it's a fool looks for logic in the chambers of the human heart." Ulysses Everett McGill.
Do not send technical questions via personal messaging - they will be ignored.

fraser_s

#include <Wire.h>

#define DEVICE (0x53)    //ADXL345 device address
#define TO_READ (6)        //num of bytes we are going to read each time (two bytes for each axis)

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

void setup()
{
 Wire.begin();        // join i2c bus (address 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()
{
 int regAddress = 0x32;    //first axis-acceleration-data register on the ADXL345
 int x, y, z;
 
 readFrom(DEVICE, regAddress, TO_READ, buff); //read the acceleration 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);
 
 //It appears that delay is needed in order not to clog the port
 delay(1000);
}

//---------------- Functions
//Writes val to address register on device
void writeTo(int device, byte address, byte val) {
  Wire.beginTransmission(device); //start transmission to device
  Wire.send(address);        // send register address
  Wire.send(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.send(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 = Wire.receive(); // receive a byte
   i++;
 }
 Wire.endTransmission(); //end transmission
}

if (

fraser_s

thats the code i have so far, all i want to the arduino to do is recognise when the accelerometer has been picked up, then put down again, by displaying a simple message in the serial monitor.

AWOL

Picking up would imply some movement in the Z axis, so that's the one I'd monitor.
You'd need to detect some acceleration over a threshold for more than, say, 100ms.

Please use the # icon in the editor when posting code.
"Pete, it's a fool looks for logic in the chambers of the human heart." Ulysses Everett McGill.
Do not send technical questions via personal messaging - they will be ignored.

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