_34_accelerometer_code.ino

/*
   Project name: GY-85 — A quick datasheet study #arduSerie 34
     ADXL345 How it Works
     Flavour I - Accelerometer code
     Hex File: _34_accelerometer_code.ino
   Revision History:
     Jun, 2017
       v 1.0 - Medium webpage: https://goo.gl/rdL4uY
     Sept, 2017
       v 1.1 - Removed: if (Wire.available() <= 1) will always true - it can be removed 
               Thanks to https://github.com/Koepel
   Description:
         In this code we will unlock the accelerometer — ADXL335— off the GY-85 board!
   MCU:                  Arduino 1.8.2 - @16MHz       http://www.arduino.cc/
   ADXL345:              ADXL345 - GY-85 Datasheet    https://goo.gl/uOZc2b
   Connections:
      See Official youtube channel vids: https://goo.gl/unfHZA
   Based on:  MEMS Accelerometer Gyroscope Magnetometer & Arduino
   from http://howtomechatronics.com/how-it-works/electrical-engineering/mems-accelerometer-gyrocope-magnetometer-arduino/
   Datasheet Atmega328P  8-bit AVR Microcontrollers:
   http://www.atmel.com/Images/Atmel-42735-8-bit-AVR-Microcontroller-ATmega328-328P_Datasheet.pdf

   This program is free software: you can redistribute it and/or modify
   it under the terms of the GNU General Public License v3 as published by
   the Free Software Foundation
*/
#include <Wire.h>
//--- Accelerometer Register Addresses
#define Power_Register 0x2D
#define X_Axis_Register_DATAX0 0x32 // Hexadecima address for the DATAX0 internal register.
#define X_Axis_Register_DATAX1 0x33 // Hexadecima address for the DATAX1 internal register.
#define Y_Axis_Register_DATAY0 0x34
#define Y_Axis_Register_DATAY1 0x35
#define Z_Axis_Register_DATAZ0 0x36
#define Z_Axis_Register_DATAZ1 0x37
int ADXAddress = 0x53;  //Device address in which is also included the 8th bit for selecting the mode, read in this case.
int X0, X1, X_out;
int Y0, Y1, Y_out;
int Z1, Z0, Z_out;
float Xa, Ya, Za;
void setup() {
  Wire.begin(); // Initiate the Wire library
  Serial.begin(9600);
  delay(100);

  Wire.beginTransmission(ADXAddress);
  Wire.write(Power_Register); // Power_CTL Register
  // Enable measurement
  Wire.write(8); // Bit D3 High for measuring enable (0000 1000)
  Wire.endTransmission();
}
void loop() {
  // X-axis
  Wire.beginTransmission(ADXAddress); // Begin transmission to the Sensor
  //Ask the particular registers for data
  Wire.write(X_Axis_Register_DATAX0);
  Wire.write(X_Axis_Register_DATAX1);
  Wire.endTransmission(); // Ends the transmission and transmits the data from the two registers
  Wire.requestFrom(ADXAddress, 2); // Request the transmitted two bytes from the two registers
  //if (Wire.available() <= 2) { //
    X0 = Wire.read(); // Reads the data from the register
    X1 = Wire.read();
    /* Converting the raw data of the X-Axis into X-Axis Acceleration
      - The output data is Two's complement
      - X0 as the least significant byte
      - X1 as the most significant byte */
    X1 = X1 << 8;
    X_out = X0 + X1;
    Xa = X_out / 256.0; // Xa = output value from -1 to +1, Gravity acceleration acting on the X-Axis
  //}
  // Y-Axis
  Wire.beginTransmission(ADXAddress);
  Wire.write(Y_Axis_Register_DATAY0);
  Wire.write(Y_Axis_Register_DATAY1);
  Wire.endTransmission();
  Wire.requestFrom(ADXAddress, 2);
  //if (Wire.available() <= 2) {
    Y0 = Wire.read();
    Y1 = Wire.read();
    Y1 = Y1 << 8;
    Y_out = Y0 + Y1;
    Ya = Y_out / 256.0;
  //}
  // Z-Axis
  Wire.beginTransmission(ADXAddress);
  Wire.write(Z_Axis_Register_DATAZ0);
  Wire.write(Z_Axis_Register_DATAZ1);
  Wire.endTransmission();
  Wire.requestFrom(ADXAddress, 2);
  //if (Wire.available() <= 2) {
    Z0 = Wire.read();
    Z1 = Wire.read();
    Z1 = Z1 << 8;
    Z_out = Z0 + Z1;
    Za = Z_out / 256.0;
  //}
  // Prints the data on the Serial Monitor
  Serial.print("Xa= ");
  Serial.print(Xa);
  Serial.print("   Ya= ");
  Serial.print(Ya);
  Serial.print("   Za= ");
  Serial.println(Za);
}