4 Duration Control Timer

1// Paul Brace
2// 30 minutes to 2 hour timer for running an external  device
3// Jan 2021
4
5#define TIME_SELECT_BUTTON 2
6#define START_BUTTON  3
7#define STOP_BUTTON 4
8#define TIME_30_LIGHT 6   //Yellow  
9#define TIME_60_LIGHT  7   //Yellow
10#define TIME_90_LIGHT 8   //Yellow
11#define TIME_120_LIGHT 9  //Yellow
12#define  ACTIVE_LIGHT 10   //Green
13#define ACTIVE_PIN 11
14
15bool timerActive;
16unsigned  long timerLength;
17unsigned long startTime;
18unsigned long duration;
19
20
21
22void  setup() {
23  pinMode(START_BUTTON, INPUT_PULLUP);
24  pinMode(STOP_BUTTON, INPUT_PULLUP);
25  pinMode(TIME_SELECT_BUTTON, INPUT_PULLUP);
26  pinMode(ACTIVE_LIGHT, OUTPUT);
27  pinMode(ACTIVE_PIN, OUTPUT);
28  pinMode(TIME_30_LIGHT, OUTPUT);
29  pinMode(TIME_60_LIGHT,  OUTPUT);
30  pinMode(TIME_90_LIGHT, OUTPUT);
31  pinMode(TIME_120_LIGHT, OUTPUT);
32  digitalWrite(ACTIVE_LIGHT, LOW);
33  digitalWrite(TIME_30_LIGHT, HIGH);
34  digitalWrite(TIME_60_LIGHT,  LOW);
35  digitalWrite(TIME_90_LIGHT, LOW);
36  digitalWrite(TIME_120_LIGHT, LOW);
37  digitalWrite(ACTIVE_PIN, LOW);
38
39  timerLength = 30;     // Default to 30  minutes
40  timerActive = false;  // Timer in inactive state
41}
42
43void WaitForStart(){
44  // Called when timer inactive and will loop until 
45  // the start button is  pressed.
46  // Also checks to see if the select time button has been pressed and
47  // changes the duration if it has.
48  while (digitalRead(START_BUTTON) == HIGH){
49    // Check if the timer select button has been pressed
50    // if so cycle through  times for each press
51    if (digitalRead(TIME_SELECT_BUTTON) == LOW){
52      switch(timerLength){
53        case 30:
54          timerLength = 60;
55          digitalWrite(TIME_30_LIGHT,  LOW);
56          digitalWrite(TIME_60_LIGHT, HIGH);
57          break;
58        case  60:
59          timerLength = 90;
60          digitalWrite(TIME_60_LIGHT, LOW);
61          digitalWrite(TIME_90_LIGHT, HIGH);
62          break;
63        case  90:
64          timerLength = 120;
65          digitalWrite(TIME_90_LIGHT, LOW);
66          digitalWrite(TIME_120_LIGHT, HIGH);
67          break;
68        case  120:
69          timerLength = 30;
70          digitalWrite(TIME_120_LIGHT, LOW);
71          digitalWrite(TIME_30_LIGHT, HIGH);
72          break;
73      }
74      // Delay to cater for button bounce and repeat if held down
75      delay(500);
76    }
77  }
78  // Start button has been pressed
79  // Timer now active
80  timerActive = true;       
81  // Record the start time in milliseconds
82  startTime  = millis();     
83  // Calculate duration to activate timer for in milliseconds
84  // Calculation will be using unsigned long aritmatic 
85  // as first argument  is an unsigned long
86  duration = timerLength * 60 * 1000;  
87  // Turn on active  light and activate relay
88  digitalWrite(ACTIVE_PIN, HIGH);
89  digitalWrite(ACTIVE_LIGHT,  HIGH);
90}
91
92void loop() {
93  // If timer is not active then wait for the  start button
94  if (!timerActive){
95    WaitForStart();
96  }
97  // The following  code will only be reached when the timer is active
98  // Check every second if  the selected time has elapsed or stop button pressed
99  while (timerActive){
100    if ((digitalRead(STOP_BUTTON) == LOW) ||
101       ((millis() - startTime) >=  duration)){
102        // Duration reached or stop button pressed so
103        //  set to not active, turn off active light and relay
104        timerActive = false;
105        digitalWrite(ACTIVE_PIN, LOW);
106        digitalWrite(ACTIVE_LIGHT, LOW);
107     }
108     // Pause for 1 second
109     delay(1000); 
110  }
111}