UK-Style 3-Way Traffic Light Simulation with Countdown Display

1#include <TM1637Display.h>
2
3// ---- Display ----
4#define CLK 8
5#define DIO 9
6TM1637Display display(CLK, DIO);
7
8// ---- Light Pins ----
9// Traffic Light A
10#define A_RED 2
11#define A_YEL 3
12#define A_GRN 4
13// Traffic Light B
14#define B_RED 5
15#define B_YEL 6
16#define B_GRN 7
17// Traffic Light C
18#define C_RED 10
19#define C_YEL 11
20#define C_GRN 12
21
22// ---- Timing ----
23const int greenTime = 5;     // seconds green is on
24const int amberTime = 3;     // seconds for amber light
25const int redAmberTime = 2;  // seconds for red+amber before green
26bool spinDirection = true;   // toggle animation direction
27
28void setup() {
29  pinMode(A_RED, OUTPUT);
30  pinMode(A_YEL, OUTPUT);
31  pinMode(A_GRN, OUTPUT);
32  pinMode(B_RED, OUTPUT);
33  pinMode(B_YEL, OUTPUT);
34  pinMode(B_GRN, OUTPUT);
35  pinMode(C_RED, OUTPUT);
36  pinMode(C_YEL, OUTPUT);
37  pinMode(C_GRN, OUTPUT);
38
39  display.setBrightness(7);
40  allRed();
41  delay(1000);
42}
43
44void loop() {
45  runLight(1, A_RED, A_YEL, A_GRN);
46  runLight(2, B_RED, B_YEL, B_GRN);
47  runLight(3, C_RED, C_YEL, C_GRN);
48}
49
50// ---- Sequence for one light ----
51void runLight(int lightNum, int redPin, int yelPin, int grnPin) {
52  // ---- All lights start red ----
53  allRed();
54
55  // ---- Red + Amber (prepare) ----
56  digitalWrite(redPin, HIGH);
57  digitalWrite(yelPin, HIGH);
58  digitalWrite(grnPin, LOW);
59  countdown(lightNum, redAmberTime);
60
61  // ---- Green ----
62  allRed();
63  digitalWrite(redPin, LOW);
64  digitalWrite(yelPin, LOW);
65  digitalWrite(grnPin, HIGH);
66  countdown(lightNum, greenTime);
67
68  // ---- Amber ----
69  allRed();
70  digitalWrite(redPin, LOW);
71  digitalWrite(yelPin, HIGH);
72  digitalWrite(grnPin, LOW);
73  changeover();
74
75  // ---- Back to Red ----
76  allRed();
77
78  // ---- Both red + animation ----
79  spinRing(spinDirection);
80  spinDirection = !spinDirection;
81}
82
83// ---- Countdown Display ----
84void countdown(int lightNum, int seconds) {
85  for (int i = seconds; i > 0; i--) {
86    int displayVal = (lightNum * 100) + i;  // e.g. 1:05 = 105
87    display.showNumberDecEx(displayVal, 0b01000000, true);
88    delay(1000);
89  }
90  display.clear();
91}
92
93// ---- All lights red ----
94void allRed() {
95  digitalWrite(A_RED, HIGH);
96  digitalWrite(A_YEL, LOW);
97  digitalWrite(A_GRN, LOW);
98
99  digitalWrite(B_RED, HIGH);
100  digitalWrite(B_YEL, LOW);
101  digitalWrite(B_GRN, LOW);
102
103  digitalWrite(C_RED, HIGH);
104  digitalWrite(C_YEL, LOW);
105  digitalWrite(C_GRN, LOW);
106}
107
108// ---- Amber wave animation ----
109void changeover() {
110  uint8_t segmentOrder[] = { SEG_A, SEG_F, SEG_G, SEG_C, SEG_D, SEG_E, SEG_B };
111  int segmentCount = sizeof(segmentOrder) / sizeof(segmentOrder[0]);
112  unsigned long endTime = millis() + (amberTime * 1000UL);
113
114  while (millis() < endTime) {
115    for (int step = 0; step < segmentCount; step++) {
116      uint8_t segs[4];
117      for (int d = 0; d < 4; d++) {
118        int segIndex = (step - d + segmentCount) % segmentCount;
119        segs[d] = segmentOrder[segIndex];
120      }
121      display.setSegments(segs);
122      delay(120);
123    }
124  }
125  display.clear();
126}
127
128// ---- 500ms alternating chase ring ----
129void spinRing(bool clockwise) {
130  uint8_t orderCW[] = { SEG_A, SEG_B, SEG_C, SEG_D, SEG_E, SEG_F, SEG_G };
131  uint8_t orderCCW[] = { SEG_A, SEG_F, SEG_E, SEG_D, SEG_C, SEG_B, SEG_G };
132  uint8_t* order = clockwise ? orderCW : orderCCW;
133
134  unsigned long start = millis();
135  while (millis() - start < 500) {
136    for (int i = 0; i < 7; i++) {
137      uint8_t segs[4];
138      for (int d = 0; d < 4; d++) {
139        int segIndex = (i + d) % 7;
140        segs[d] = order[segIndex];
141      }
142      display.setSegments(segs);
143      delay(60);
144    }
145  }
146  display.clear();
147}