ESP32でボタンによるLED制御（トグル）

1// ─────────────────────────────────────────
2//   BlueGrays · bluegrays.com
3//   ESP32 LED Control with Pushbutton (Toggle)
4// ─────────────────────────────────────────
5// Each press of the button toggles the LED: on becomes off, off becomes
6// on. A 50 ms debounce makes sure one press gives exactly one toggle.
7//
8// Pins:
9//   GPIO 5 -> Red LED (with a 220 ohm resistor)
10//   GPIO 4 -> Button (other leg to GND)
11
12const int LED_PIN = 5;      // LED output
13const int BUTTON_PIN = 4;   // Button input
14
15bool ledState = false;               // Is the LED on now
16bool lastButton = HIGH;              // Previous button reading
17bool stableButton = HIGH;            // Stable (debounced) button state
18unsigned long lastChange = 0;        // Last time the reading changed (ms)
19const unsigned long DEBOUNCE = 50;   // Debounce time (ms)
20
21void setup() {
22  pinMode(LED_PIN, OUTPUT);
23  pinMode(BUTTON_PIN, INPUT_PULLUP);  // Reads HIGH when not pressed
24}
25
26void loop() {
27  bool buttonState = digitalRead(BUTTON_PIN);
28
29  // Restart the timer whenever the reading changes
30  if (buttonState != lastButton) lastChange = millis();
31
32  // A reading that stays the same for DEBOUNCE ms counts as stable. The LED toggles once, only when
33  // the stable state turns LOW (a new press).
34  if (millis() - lastChange > DEBOUNCE && buttonState != stableButton) {
35    stableButton = buttonState;
36    if (stableButton == LOW) {
37      ledState = !ledState;
38      digitalWrite(LED_PIN, ledState);
39    }
40  }
41  lastButton = buttonState;
42}
43