Automated Railway Reverse Loop

1//  LOOP FOR APP DEMO //
2
3// L298
4#define L298_ENA 6
5#define  L298_IN1 7
6#define L298_IN2 5
7#define L298_IN3 4
8#define L298_IN4 2
9#define  L298_ENB 3
10
11// SWITCH MACHINE
12#define STRAIGHT 9
13#define BRANCH 10
14
15//  SENSOR
16#define SENSOR 11
17
18// VARIABLES //
19bool stringComplete = false;
20String  inputString = ""; 
21byte speedArray [] = {60, 80, 100, 120, 140, 170, 200, 230,  255};
22byte speedTrain = 0;
23bool directionForward = false, directionBackward  = false;
24bool sensorLatch = false;
25bool flagTimer = false;
26unsigned long  millisLoop;
27
28void setup() {
29
30// Initializing Serial
31  Serial.begin(9600);
32  inputString.reserve(4); 
33
34// Initializing Motor-Driver
35  pinMode(L298_ENA,  OUTPUT); 
36  pinMode(L298_IN1, OUTPUT); 
37  pinMode(L298_IN2, OUTPUT);
38  pinMode(L298_IN3,  OUTPUT); 
39  pinMode(L298_IN4, OUTPUT); 
40  pinMode(L298_ENB, OUTPUT);  
41
42//  Initializing Switch Machine 
43  pinMode(STRAIGHT, OUTPUT); 
44  pinMode(BRANCH,  OUTPUT);
45
46// Initializing Sensor 
47  pinMode(SENSOR, INPUT); 
48
49//  SET TURNOUT TO DEFAULT POSITION  
50  digitalWrite(STRAIGHT, HIGH);
51  delay(600);
52  digitalWrite(STRAIGHT, LOW);
53
54}
55
56void loop() {
57
58// ---- START  PARSING INCOMING APP COMMANDS
59  if (stringComplete) {
60
61    if (inputString.charAt(0)  =='a') {
62
63      // Speed 
64      if (inputString.charAt(1) =='0') {
65        if (inputString.charAt(2) =='0') speedTrain = 0;
66        if (inputString.charAt(2)  =='2') speedTrain = speedArray[0];
67        if (inputString.charAt(2) =='4') speedTrain  = speedArray[1];
68        if (inputString.charAt(2) =='6') speedTrain = speedArray[2];
69        if (inputString.charAt(2) =='8') speedTrain = speedArray[3];
70      }  
71      if (inputString.charAt(1) =='1') {
72        if (inputString.charAt(2)  =='0') speedTrain = speedArray[4];
73        if (inputString.charAt(2) =='2') speedTrain  = speedArray[5];
74        if (inputString.charAt(2) =='4') speedTrain = speedArray[6];
75        if (inputString.charAt(2) =='6') speedTrain = speedArray[7];
76        if  (inputString.charAt(2) =='8') speedTrain = speedArray[8];
77      }
78
79      //  Direction and Stop
80      if (inputString.charAt(1) =='d') {
81        if (inputString.charAt(2)  =='f') { // (f) Forward
82          digitalWrite(L298_IN1, HIGH);
83          digitalWrite(L298_IN2,  LOW);
84          directionForward = true;
85          directionBackward = false;
86        }
87        if (inputString.charAt(2) =='b') { // (b) Backward
88          digitalWrite(L298_IN1,  LOW);
89          digitalWrite(L298_IN2, HIGH);
90          directionForward =  false;
91          directionBackward = true;          
92        }
93        if  (inputString.charAt(2) =='s') { // (s) Stop button
94          digitalWrite(L298_IN1,  LOW);
95          digitalWrite(L298_IN2, LOW);
96          speedTrain = 0;
97          directionForward = false;
98          directionBackward = false;          
99        } 
100      }
101      analogWrite(L298_ENA, speedTrain); // Throttle
102      analogWrite(L298_ENB, speedTrain); // Throttle      
103    }
104
105    inputString  = "";
106    stringComplete = false;
107  }
108
109// ---- LOOP 
110  // Train  in sensor area
111  if (digitalRead(SENSOR) == HIGH) {
112    // To check STOP state
113    if (directionForward != directionBackward) {
114      directionForward = !directionForward;
115      directionBackward = !directionBackward;
116      // To change polarity of  Main Line
117      if (directionForward) {
118        digitalWrite(L298_IN1, HIGH);
119        digitalWrite(L298_IN2, LOW);        
120      } 
121      else {
122        digitalWrite(L298_IN1,  LOW);
123        digitalWrite(L298_IN2, HIGH);          
124      }
125      //  Switching turnout to branch
126        digitalWrite(STRAIGHT, LOW);       
127        digitalWrite(BRANCH,  HIGH);         
128    }
129    sensorLatch = true;
130  }  
131
132  // The train  left the sensor
133  if (sensorLatch && digitalRead(SENSOR) == LOW) {
134    millisLoop  = millis();
135    sensorLatch = false;
136    flagTimer = true;
137  }
138
139  // Delay time is up (5000 - 5 sec.) 
140  if (millis() > millisLoop + 5010) flagTimer  = false;
141
142  if ((millis() > millisLoop + 5000) && flagTimer) { 
143    Serial.println("Delay  time is up");
144    // Switching turnout to straight
145    digitalWrite(BRANCH,  LOW);       
146    digitalWrite(STRAIGHT, HIGH);  
147  }      
148
149  // To  check STOP state
150    if ((directionForward != directionBackward) && digitalRead(SENSOR)  == LOW) {
151
152    // To change polarity of Loop Line
153    if (directionForward)  {
154      digitalWrite(L298_IN3, HIGH);
155      digitalWrite(L298_IN4, LOW);        
156    } 
157    else {
158      digitalWrite(L298_IN3, LOW);
159      digitalWrite(L298_IN4,  HIGH);          
160    }
161  }  
162}
163
164
165//// FUNCTIONS ////
166
167void  serialEvent() {
168  if (Serial.available()) {
169    char inChar = (char)Serial.read();
170    inputString += inChar;
171    if (inChar == 'z') {
172      stringComplete =  true;
173    }
174  }
175}