Model Train Control

1/*
2  Train control
3  This code is developed to "test" drive
4  a model train between two gates made of a LED and LDR.
5
6  Parts required:
7  1 - arduino uno/mega or compatible
8  1 - arduino motor shield R3
9  2 - Led  brite white (5mm)
10  2 - Ldr (A 9013 photo resistor 5mm) 
11  2 - 10K resistor
12  2 - 220 Ohm resistor
13  1 - model train 
14
15  Created 4 October 2016
16  by Kitemasters
17
18  This code is part of the public domain
19*/
20// --------CONSTANTS  (won't change)---------------
21
22int sens_L_Pin = A4;                         //  the pin number for ldr L
23int sens_R_Pin = A5;                         // the  pin number for ldr R
24int led_L_Pin = 4;                           // the pin  number for the L LED
25int led_R_Pin = 5;                           // the pin  number for the R LED
26int motor_Pin = 3;                           // the pin  number for the motor speed
27int brake_Pin = 9;                           // the  pin number for the motor brake
28int direction_Pin = 12;                      //  the pin number for the motor direction
29int current_sens_Pin = A0;                   //  the pin number for the current sensor
30
31int read_sens_Interval = 200;                //  millisecs between reading sensors
32int motor_Acc_Interval = 100;                //  millisecs between acceleration steps
33int motor_Dec_Interval = 10;                 //  millisecs between deceleration steps
34
35//------------ VARIABLES (will change)---------------------
36
37unsigned  long currentMillis = 0;               // stores the value of millis() in each iteration  of loop()
38unsigned long previous_sens_Millis = 0;        // will store the last  time sensors are read
39unsigned long previous_Acc_Millis = 0;         // will  store time of last acceleration step
40unsigned long previous_Dec_Millis = 0;         //  will store time of last deceleration step
41
42int sensLreading = 0;                          //  declare variable and set value for left sensor reading
43int sensRreading = 0;                          // declare variable and set value for right sensor reading
44int  max_Speed = 200;                           // declare variable and set value for  maximum Speed (0 to 255)
45int Speed = 0;                                 // declare  variable and set value for current Speed (0 to 255)
46boolean direct = HIGH;                         //  declare variable and set value for direction to HIGH (HIGH = left)
47
48#define  STATE_START 1                          // declare value 0 to be STATE_START
49#define  STATE_RUN 2                            // declare value 1 to be STATE_RUN
50#define  STATE_DECELERATE 3                     // declare value 2 to be STATE_DECELERATE
51#define  STATE_TURN 4                           // declare value 3 to be STATE_TURN
52#define  STATE_ACCELERATE 5                     // declare value 4 to be STATE_ACCELERATE
53
54int  state = STATE_START;                       // declare variable "state" and set  value to STATE_START
55
56//========================================
57
58void  setup() {
59
60  Serial.begin(9600);
61
62  pinMode(led_L_Pin, OUTPUT);                    //  set led_L_Pin as output
63  pinMode(led_R_Pin, OUTPUT);                    // set  led_R_Pin as output
64  pinMode(motor_Pin, OUTPUT);                    // set motor_Pin  as output
65  pinMode(brake_Pin, OUTPUT);                    // set brake_Pin as  output
66  pinMode(direction_Pin, OUTPUT);                // set direction_Pin  as output
67  pinMode(sens_L_Pin, INPUT);                    // set sens_L_Pin  as input
68  pinMode(sens_R_Pin, INPUT);                    // set sens_R_Pin as  input
69  pinMode(current_sens_Pin, INPUT);              // set current_sens_Pin  as input
70
71}
72//========================================
73
74void loop()  {
75
76  currentMillis = millis();                      // store the latest value  of millis()
77  read_sens();                                   // read the sensors
78
79  switch (state)                                 // state switch
80  {
81    case  STATE_START:
82      Start();
83      break;
84
85    case STATE_ACCELERATE:
86      Accelerate();
87      break;
88
89    case STATE_DECELERATE:
90      Decelerate();
91      break;
92
93    case STATE_TURN:
94      Turn();
95      break;
96
97    case STATE_RUN:
98      break;
99  }
100}
101//========================================
102
103void  read_sens() {
104
105  if (currentMillis - previous_sens_Millis >= read_sens_Interval)  {   // time is up, so read sensors
106    previous_sens_Millis = currentMillis;                             // because shooter and Koepel told me so.// save the  time we last read sensors
107    sensLreading = analogRead(sens_L_Pin);                            //  read left ldr (high value means the light is off or blockt)
108    sensRreading  = analogRead(sens_R_Pin);                            // read right ldr (high value  means the light is off or blockt)
109
110    if (sensLreading > 200 && direct ==  HIGH) {                       // if conditions are throu, the train reached left  gate***
111      digitalWrite(led_L_Pin, LOW);                                   //  turn left LED off
112      digitalWrite(led_R_Pin, HIGH);                                  //  turn right LED on
113      state = STATE_DECELERATE;                                       //  set state to "decelerate"
114      previous_Dec_Millis = currentMillis;                            //  set previous_Dec_Millis to current time
115    }
116
117    if (sensRreading > 200  && direct == LOW) {                        // if conditions are throu, the train  reached right gate***
118      digitalWrite(led_R_Pin, LOW);                                   //  turn right LED off
119      digitalWrite(led_L_Pin, HIGH);                                  //  turn left LED on
120      state = STATE_DECELERATE;                                       //  set state to "decelerate"
121      previous_Dec_Millis = currentMillis;                            //  set previous_Dec_Millis to current time
122    }  
123  }
124}
125//========================================
126
127void  Start() {
128
129  digitalWrite(led_L_Pin, HIGH);                                      //  turn left led on
130  digitalWrite(brake_Pin, LOW);                                       //  Disengage the Brake
131  digitalWrite(direction_Pin, direct);                                //  Establishes direction of the train
132  state = STATE_ACCELERATE;                                           //  set state to "accelerate"
133  previous_Acc_Millis = currentMillis;                                //  set previous_Acc_Millis to current time
134}
135//========================================
136
137void  Accelerate() {
138
139  if (currentMillis - previous_Acc_Millis >= motor_Acc_Interval)  {    // check interval time
140    previous_Acc_Millis = currentMillis;                              //  because shooter and Koepel told me so.//last time of acceleration step
141    Speed  = Speed + 1;                                                // add 1 to speed
142    analogWrite(motor_Pin, Speed);                                    // send Speed  to motor_Pin
143    if (Speed == max_Speed) {                                         //  if speed reach max speed
144      state = STATE_RUN;                                              //  set state to "run"
145    }
146  }
147}
148//========================================
149
150void  Decelerate() {
151
152  if (currentMillis - previous_Dec_Millis >= motor_Dec_Interval)  {    // check interval time
153    previous_Dec_Millis = currentMillis;                              //  because shooter and Koepel told me so.//last time of acceleration step
154    Speed  = Speed - 1;                                                // subtract 1 of speed
155    analogWrite(motor_Pin, Speed);                                    // send Speed  to motor_Pin
156    if (Speed == 0) {                                                 //  if speed reach 0
157      state = STATE_TURN;                                             //  set state to "turn"
158    }
159  }
160}
161//========================================
162
163void  Turn() {
164
165  if (direct == HIGH) {                                               //  flip direction
166    direct = LOW;
167    digitalWrite(direction_Pin, direct);                              // establishes right direction of train
168  }
169  else {
170    direct = HIGH;
171    digitalWrite(direction_Pin, direct);                              //  establishes left direction of train
172  }
173  state = STATE_ACCELERATE;                                           //  set state to "accelerate"
174  previous_Acc_Millis = currentMillis;                                //  set previous_Acc_Millis to current time
175}
176//========================================END
177