SMART HELMET: ACCIDENT DETECTION SYSTEM

1#include <Wire.h>
2
3#include <MPU6050_tockn.h>
4
5#include <TinyGPS++.h>
6
7#include <SoftwareSerial.h>
8
9 
10
11// Constants
12
13#define GPS_BAUD 9600
14
15#define SERIAL_BAUD 9600
16
17#define GYRO_THRESHOLD 200.0    // deg/s (sudden rotation)
18
19#define TILT_ANGLE_THRESHOLD 60 // degrees from vertical
20
21#define SPEED_CHANGE_THRESHOLD 15.0 // km/h sudden stop
22
23#define ALERT_COOLDOWN 10000    // 10 seconds
24
25 
26
27// Pins
28
29const uint8_t GPS_RX = 4;
30
31const uint8_t GPS_TX = 3;
32
33 
34
35const uint8_t STATUS_LED = 13;
36
37 
38
39MPU6050 mpu(Wire);
40
41TinyGPSPlus gps;
42
43SoftwareSerial gpsSerial(GPS_RX, GPS_TX);
44
45 
46
47// State variables
48
49float prevSpeed = 0;
50
51uint32_t lastAlertTime = 0;
52
53 
54
55void setup() {
56
57  pinMode(STATUS_LED, OUTPUT);
58
59  Serial.begin(SERIAL_BAUD);
60
61  gpsSerial.begin(GPS_BAUD);
62
63  Wire.begin();
64
65 
66
67  mpu.begin();
68
69  mpu.calcGyroOffsets(true);
70
71 
72
73  Serial.println(F("Gyro-Based Crash Detection Ready"));
74
75}
76
77 
78
79void loop() {
80
81  static uint32_t lastUpdate = 0;
82
83  const uint32_t currentMillis = millis();
84
85   
86
87    mpu.update();
88
89   
90
91    // 1. Detect sudden rotation (gyroscope)
92
93    const float gyroX = mpu.getGyroX();
94
95    const float gyroY = mpu.getGyroY();
96
97    const float gyroZ = mpu.getGyroZ();
98
99    const float gyroMagnitude = sqrt(gyroX*gyroX + gyroY*gyroY + gyroZ*gyroZ);
100
101 
102
103    // 2. Check sustained tilt (using gravity vector)
104
105    const float accelY = mpu.getAccY();
106
107    const float accelZ = mpu.getAccZ();
108
109    const float tiltAngle = atan2(accelY, accelZ) * 180/PI; // Vertical tilt
110
111 
112
113    // 3. Detect sudden stop (GPS speed)
114
115    const float currentSpeed = gps.speed.kmph();
116
117    const float speedDelta = abs(prevSpeed - currentSpeed);
118
119    prevSpeed = currentSpeed;
120
121 
122
123    // Accident condition check
124
125    if((gyroMagnitude > GYRO_THRESHOLD && abs(tiltAngle) > TILT_ANGLE_THRESHOLD)||
126
127       (prevSpeed > 10 && speedDelta > SPEED_CHANGE_THRESHOLD) ) {
128
129      triggerAlert();
130
131    }
132
133 
134
135}
136
137 
138
139void triggerAlert() {
140
141  if(millis() - lastAlertTime < ALERT_COOLDOWN) return;
142
143  lastAlertTime = millis();
144
145 
146
147  digitalWrite(STATUS_LED, HIGH);
148
149   Serial.println(F("@ACCIDENT_SOS 28.06, 77.03"));   //assumed gps values due to poor connectivity of gps inside a room
150
151 
152
153  if(gps.location.isValid()) {
154
155    Serial.print(F("Location: "));
156
157    Serial.print(gps.location.lat(), 6);
158
159    Serial.print(",");
160
161    Serial.println(gps.location.lng(), 6);
162
163  }
164
165 
166
167  delay(500);
168
169  digitalWrite(STATUS_LED, LOW);
170
171
172}