Touch-to-Light: Control LEDs with Arduino and HMI Display

1char buffer[40];
2int idx = 0;
3
4const int redLED = 9;
5const int yellowLED = 8;
6const int greenLED = 7;
7
8void setup() {
9  Serial.begin(115200);
10  Serial1.begin(115200);
11
12  pinMode(redLED, OUTPUT);
13  pinMode(yellowLED, OUTPUT);
14  pinMode(greenLED, OUTPUT);
15
16  // Start all OFF
17  digitalWrite(redLED, LOW);
18  digitalWrite(yellowLED, LOW);
19  digitalWrite(greenLED, LOW);
20
21  Serial.println("System Ready...");
22}
23
24void loop() {
25  while (Serial1.available()) {
26    char c = Serial1.read();
27
28    if (idx < sizeof(buffer) - 1) {
29      buffer[idx++] = c;
30    }
31
32    if (c == '\n' || c == '\r') {   // End of packet
33      buffer[idx] = '\0';
34      if (idx > 0) {
35        parsePacket(buffer);
36      }
37      idx = 0;  // Reset for next packet
38    }
39  }
40}
41
42void parsePacket(char *pkt) {
43  Serial.print("RX: ");
44  Serial.println(pkt);
45
46  int page = 0, type = 0, id = 0, value = -1;
47
48  if (sscanf(pkt, "P%dT%dI%dV%d", &page, &type, &id, &value) == 4) {
49    if (value == 1) {   //  Only act on press
50      if (page == 5 && type == 11 && id == 0) {
51        // Red
52        digitalWrite(redLED, HIGH);
53        digitalWrite(yellowLED, LOW);
54        digitalWrite(greenLED, LOW);
55        Serial.println("Red LED -> ON");
56      }
57      else if (page == 5 && type == 11 && id == 1) {
58        // Yellow
59        digitalWrite(redLED, LOW);
60        digitalWrite(yellowLED, HIGH);
61        digitalWrite(greenLED, LOW);
62        Serial.println("Yellow LED -> ON");
63      }
64      else if (page == 6 && type == 11 && id == 0) {
65        // Green
66        digitalWrite(redLED, LOW);
67        digitalWrite(yellowLED, LOW);
68        digitalWrite(greenLED, HIGH);
69        Serial.println("Green LED -> ON");
70      }
71    }
72    //  Ignore V=0 (release)
73  }
74}