Trying to use Tap Detection solution using ADXL345 with Arduino

Question

I am using ADXL345 sensor connecting with Arduino via I2C interface, I am able to test the data at tri-axial axis but as there are some other features also, which I am going to try with Tap detection method as I didn't use TAP THRESH register and instead of that I am using the registers (in decimal) of Tap latency - 33, Tap Duration - 34, Tap Window - 35.

For which I just started with raw code,

#include <Wire.h>

// ADXL345 I2C address is 0x53(83)
#define Addr 0x53

void setup()
{
  // Initialise I2C communication as MASTER
  Wire.begin();
  // Initialise serial communication, set baud rate = 9600
  Serial.begin(9600);

  // Start I2C Transmission
  Wire.beginTransmission(Addr);
  // Select bandwidth rate register
  Wire.write(0x2C);
  // Normal mode, Output data rate = 100 Hz
  Wire.write(0x0A);
  // Stop I2C transmission
  Wire.endTransmission();

  // Start I2C Transmission
  Wire.beginTransmission(Addr);
  // Select power control register
  Wire.write(0x2D);
  // Auto-sleep disable
  Wire.write(0x08);
  // Stop I2C transmission
  Wire.endTransmission();

  // Start I2C Transmission
  Wire.beginTransmission(Addr);
  // Select data format register
  Wire.write(0x31);
  // Self test disabled, 4-wire interface, Full resolution, Range = +/-2g
  Wire.write(0x08);
  // Stop I2C transmission
  Wire.endTransmission();
  delay(300);
 }

 void loop()
 {
   unsigned int data[3];
   for(int i = 0; i < 3; i++)
   {
    // Start I2C Transmission
    Wire.beginTransmission(Addr);
    // Select data register
    Wire.write((33 + i));
    // Stop I2C transmission
    Wire.endTransmission();

    // Request 1 byte of data
    Wire.requestFrom(Addr, 1);

    //Read Three Bytes 
    if(Wire.available() == 1)
    {
      data[i] = Wire.read();
    }
 }
   int TAP_DUR = data[1];
   int TAP_LAT = data[2];
   int TAP_WIN = data[3];

   Serial.print("TAP DURATION: ");
   Serial.println(TAP_DUR);
   Serial.print("TAP Latency: ");
   Serial.println(TAP_LAT);
   Serial.print("Tap Window : ");
   Serial.println(TAP_WIN);
   delay(3000);
   }

which is not working properly, and giving the result like this

TAP DURATION: 0
TAP Latency: 0
Tap Window : 22272
TAP DURATION: 0
TAP Latency: 0
Tap Window : 22272
TAP DURATION: 0
TAP Latency: 0
Tap Window : 22272

The main aim is to test the no of tap count and duration between single tap and double tap rather than using any library I need to work with the code I have been making.

Suggestion and bits of advice to make it work will be welcome.

Answer 1

the arrays are indexed from 0 but you assign to TAP_ variables array values indexed 1,2,3.

Are you sure the sensor is wired ok? Did it work with a library example?