Accelerometer + button

arduino.ino

#include <Wire.h>  // Wire library - used for I2C communication

int ADXL345 = 0x53; // The ADXL345 sensor I2C address

float X_out, Y_out, Z_out;  // Outputs

const int BUTTON_READ_PIN = 5;
const int BUTTON_POWER_PIN = 6;

void setup() {
  Serial.begin(9600); // Initiate serial communication for printing the results on the Serial monitor
  Wire.begin(); // Initiate the Wire library
  // Set ADXL345 in measuring mode
  Wire.beginTransmission(ADXL345); // Start communicating with the device 
  Wire.write(0x2D); // Access/ talk to POWER_CTL Register - 0x2D
  // Enable measurement
  Wire.write(8); // (8dec -> 0000 1000 binary) Bit D3 High for measuring enable 
  Wire.endTransmission();

  pinMode(BUTTON_READ_PIN, INPUT_PULLUP);
  pinMode(BUTTON_POWER_PIN, OUTPUT);
  digitalWrite(BUTTON_POWER_PIN, HIGH);

  delay(10);
}

void loop() {
  // === Read acceleromter data === //
  Wire.beginTransmission(ADXL345);
  Wire.write(0x32); // Start with register 0x32 (ACCEL_XOUT_H)
  Wire.endTransmission(false);
  Wire.requestFrom(ADXL345, 6, true); // Read 6 registers total, each axis value is stored in 2 registers
  X_out = ( Wire.read()| Wire.read() << 8); // X-axis value
  X_out = X_out/256; //For a range of +-2g, we need to divide the raw values by 256, according to the datasheet
  Y_out = ( Wire.read()| Wire.read() << 8); // Y-axis value
  Y_out = Y_out/256;
  Z_out = ( Wire.read()| Wire.read() << 8); // Z-axis value
  Z_out = Z_out/256;

  Serial.print("{\"type\":\"acc\",\"x\":");
  Serial.print(X_out);
  Serial.print(",\"y\":");
  Serial.print(Y_out);
  Serial.print(",\"z\":");
  Serial.print(Z_out);
  Serial.println("}");
  
  Serial.print("{\"type\":\"btn\",\"s\":");
  if (digitalRead(BUTTON_READ_PIN)) {
    Serial.print("true");
  } else {
    Serial.print("false");
  }
  Serial.println("}");

  Serial.println("{\"type\":\"ver\",\"c\":\"SECRETVALUE\"}");

  delay(100);
}