bouton-led.ino
A button on D3 with internal pull-up, cleanly counted by the 40 ms filter. On NodeMCU GPIO0 is also the boot pin: holding it at power-on would drop the board into flash mode.
Hardware required
An ESP-12E module (ESP8266EX, 2.4 GHz Wi-Fi) mounted on a NodeMCU / Wemos D1 mini board, powered over micro-USB. 1 push button (D3 to GND).
Wiring
Button between D3 and GND; internal pull-up enabled. Boot-safe alternative: D1/D2 (GPIO4/5). Avoid GPIO15 (TX) and GPIO16.
How it works
The level is sampled continuously; an edge only counts after 40 ms of stability. INPUT_PULLUP inverts logic: pressed = LOW, hence the == LOW test. In the Arduino IDE, install the « esp8266 » package, select « NodeMCU 1.0 (ESP-12E Module) » then Upload (hold GPIO0 LOW if flashing fails). The A0 ADC reads 0-1 V (NodeMCU divider: 0-3.3 V).
Going further
Two buttons for a menu (up/down/OK), or deep-sleep wake on that same pin.
bouton-led.ino
// Bouton sur D3 (GPIO0, vers GND) + compteur anti-rebond 40 ms.
const int BOUTON = 0; // D3 — attention : GPIO0 = broche de boot !
const int LED = 2; // D4
const unsigned long ANTI_REBOND = 40;
bool dernier = HIGH, stable = HIGH;
unsigned long bord = 0;
int compteur = 0;
void setup() {
pinMode(BOUTON, INPUT_PULLUP);
pinMode(LED, OUTPUT);
Serial.begin(115200);
}
void loop() {
bool lu = digitalRead(BOUTON);
unsigned long t = millis();
if (lu != dernier) bord = t;
if (t - bord >= ANTI_REBOND && lu != stable) {
stable = lu;
if (stable == LOW) {
compteur++;
digitalWrite(LED, LOW); // LED activee (actif-bas)
Serial.printf("Appui n°%d\n", compteur);
} else {
digitalWrite(LED, HIGH);
}
}
dernier = lu;
}