Rocket Auto Abort System!

//DeltaSpaceSystems2019//

#include <elapsedMillis.h>
#include "Wire.h" // This library allows you to communicate with I2C devices.
int led = 3;
int relay = 2;
int a;
int ax;
int ay;
int az;
int i;
const int MPU_ADDR = 0x68; // I2C address of the MPU-6050. If AD0 pin is set to HIGH, the I2C address will be 0x69.
int16_t accelerometer_x, accelerometer_y, accelerometer_z; // variables for accelerometer raw data
int16_t gyro_x, gyro_y, gyro_z; // variables for gyro raw data
int16_t temperature; // variables for temperature data
char tmp_str[7]; // temporary variable used in convert function
char* convert_int16_to_str(int16_t i) { // converts int16 to string. Moreover, resulting strings will have the same length in the debug monitor.
  sprintf(tmp_str, "%6d", i);
  return tmp_str;
 
}
void setup() {
  Serial.begin(9600);
  pinMode(relay, OUTPUT);
  digitalWrite(relay, LOW);
   pinMode(led, OUTPUT);
  digitalWrite(led, LOW);
  Wire.begin();
  Wire.beginTransmission(MPU_ADDR); // Begins a transmission to the I2C slave (GY-521 board)
  Wire.write(0x6B); // PWR_MGMT_1 register
  Wire.write(0); // set to zero (wakes up the MPU-6050)
  Wire.endTransmission(true);
}
void loop() {
  Wire.beginTransmission(MPU_ADDR);
  Wire.write(0x3B); // starting with register 0x3B (ACCEL_XOUT_H) [MPU-6000 and MPU-6050 Register Map and Descriptions Revision 4.2, p.40]
  Wire.endTransmission(false); // the parameter indicates that the Arduino will send a restart. As a result, the connection is kept active.
  Wire.requestFrom(MPU_ADDR, 7*2, true); // request a total of 7*2=14 registers
  
  // "Wire.read()<<8 | Wire.read();" means two registers are read and stored in the same variable
  accelerometer_x = Wire.read()<<8 | Wire.read(); // reading registers: 0x3B (ACCEL_XOUT_H) and 0x3C (ACCEL_XOUT_L)
  accelerometer_y = Wire.read()<<8 | Wire.read(); // reading registers: 0x3D (ACCEL_YOUT_H) and 0x3E (ACCEL_YOUT_L)
  accelerometer_z = Wire.read()<<8 | Wire.read(); // reading registers: 0x3F (ACCEL_ZOUT_H) and 0x40 (ACCEL_ZOUT_L)
  temperature = Wire.read()<<8 | Wire.read(); // reading registers: 0x41 (TEMP_OUT_H) and 0x42 (TEMP_OUT_L)
  gyro_x = Wire.read()<<8 | Wire.read(); // reading registers: 0x43 (GYRO_XOUT_H) and 0x44 (GYRO_XOUT_L)
  gyro_y = Wire.read()<<8 | Wire.read(); // reading registers: 0x45 (GYRO_YOUT_H) and 0x46 (GYRO_YOUT_L)
  gyro_z = Wire.read()<<8 | Wire.read(); // reading registers: 0x47 (GYRO_ZOUT_H) and 0x48 (GYRO_ZOUT_L)
  
  // print out data
  Serial.print("aX,"); Serial.print(convert_int16_to_str(accelerometer_x));
  Serial.print(",aY,"); Serial.print(convert_int16_to_str(accelerometer_y));
  Serial.print(",aZ,"); Serial.print(convert_int16_to_str(accelerometer_z));
  // the following equation was taken from the documentation [MPU-6000/MPU-6050 Register Map and Description, p.30]
  Serial.print(",tmp,"); Serial.print(temperature/340.00+36.53);
  Serial.print(",gX,"); Serial.print(convert_int16_to_str(gyro_x));
  Serial.print(",gY,"); Serial.print(convert_int16_to_str(gyro_y));
  Serial.print(",gZ,"); Serial.print(convert_int16_to_str(gyro_z));
ax=accelerometer_x/100;
ay=accelerometer_y/100;
az=accelerometer_z/100;

  a=(sq(ax)+sq(ay));    //gets tilt calc
  Serial.print(",Calculation,"); Serial.print(a);
  Serial.println();

  if (a>8000){    // this detects launch acceleration
    digitalWrite(relay, HIGH);
 delay(5000);
 digitalWrite(relay, LOW);}
  Serial.print("Fire Pyro");
    Serial.println();
    digitalWrite(led, HIGH);
  delay(100);
 digitalWrite(led, LOW);

  }