reveil.ino
The SD sketch's NTP clock becomes an alarm: current time compared to the 07:30 slot, audio alarm on the speaker, clean stop on button A. The NTP-offset snooze shows the price of no RTC.
Hardware required
An M5Stack Core Basic/Gray (ESP32 in an enclosure with a 320×240 TFT, A/B/C buttons, speaker, microSD slot, 110 mAh battery). Wi-Fi for time; no component.
Wiring
No wiring. If Wi-Fi drops, the clock freezes: the alarm stops firing (fail-safe).
How it works
configTime drives the system clock via SNTP; the loop compares tm_hour/tm_min. wasPressed debounces the stop. The snooze reconfigures the offset to push the time back 10 minutes. In the Arduino IDE (esp32 package), board « M5Stack-Core-ESP32 »; install the « M5Stack » (or M5Unified) library from the Library Manager, then Upload.
Going further
On the M5StickC Plus2 (internal RTC) the alarm survives power cuts; here, add a battery-backed standalone buzzer.
reveil.ino
// Reveil NTP : sonne a 7 h 30, arret par bouton A, snooze 10 min par B.
#include <M5Stack.h>
#include <WiFi.h>
#include <time.h>
const char *SSID = "votre-wifi", *CLE = "votre-cle";
bool sonne = false;
void setup() {
M5.begin(true, false, true, true);
WiFi.begin(SSID, CLE);
configTime(3600 * 2, 0, "pool.ntp.org");
M5.Lcd.setTextSize(2);
}
void loop() {
M5.update();
struct tm t;
time_t maintenant = time(nullptr);
localtime_r(&maintenant, &t);
M5.Lcd.setCursor(10, 60);
M5.Lcd.printf("%02d:%02d:%02d", t.tm_hour, t.tm_min, t.tm_sec);
if (!sonne && t.tm_hour == 7 && t.tm_min == 30) sonne = true;
if (sonne) {
M5.Speaker.tone(1200, 200);
M5.Lcd.setTextColor(TFT_RED);
M5.Lcd.drawString("REVEIL !", 100, 130, 3);
if (M5.BtnA.wasPressed()) { sonne = false; M5.Speaker.mute(); }
if (M5.BtnB.wasPressed()) { // snooze 10 min
sonne = false;
configTime(3600 * 2 - 600, 0, "pool.ntp.org"); // trick : heure -10 min
}
}
delay(200);
}