#include <Wire.h>
#include <MPU6050.h>

MPU6050 mpu;

int16_t ax, ay, az;
float accel_mag;

const int vib_pin = 9;
const float threshold = 105.0; // Adjust this value to set the stroke detection sensitivity

unsigned long stroke_start_time = 0;
const unsigned long stroke_timeout = 1000; // Time limit to complete a stroke in milliseconds
bool vibration_on = false; // Variable to keep track of whether vibration motor is on or off

void setup() {
  Wire.begin();
  mpu.initialize();
  pinMode(vib_pin, OUTPUT);
  Serial.begin(115200);
}

void loop() {
  mpu.getAcceleration(&ax, &ay, &az); // Read acceleration data from the MPU6050

  accel_mag = sqrt(ax*ax + ay*ay + az*az); // Calculate the magnitude of the acceleration vector
  if (isnan(accel_mag)) {
  // Handle NaN value here, e.g. set accel_mag to a default value
  accel_mag = 0.0;
}

  Serial.print("acceleration magnitude = ");
  Serial.println(accel_mag);

  if (accel_mag > threshold) { // If a stroke is detected
    if (stroke_start_time == 0) { // If this is the first stroke of a cycle
      stroke_start_time = millis(); // Start the stroke timer
    } else if (millis() - stroke_start_time < stroke_timeout) { // If within time limit for completing a stroke
      if (vibration_on) { // If vibration motor is on
        digitalWrite(vib_pin, LOW); // Turn off the vibration motor
        vibration_on = false; // Set vibration_on to false
      }
    }
    else { // Stroke not completed within time limit
      if (!vibration_on) { // If vibration motor is not on
        digitalWrite(vib_pin, HIGH); // Activate the vibration motor
        vibration_on = true; // Set vibration_on to true
      }
      stroke_start_time = 0; // Reset the stroke timer
    }
  } else { // No stroke detected
    if (millis() - stroke_start_time >= stroke_timeout && !vibration_on) { // If within time limit for completing a stroke and vibration motor is not on
      digitalWrite(vib_pin, HIGH); // Activate the vibration motor
      vibration_on = true; // Set vibration_on to true
    } else if (vibration_on) { // If vibration motor is on
      digitalWrite(vib_pin, LOW); // Turn off the vibration motor
      vibration_on = false; // Set vibration_on to false
    }
    stroke_start_time = 0; // Reset the stroke timer
  }
  delay(10); // Add a small delay to reduce the processing load on the microcontroller
}