Yapay zekâ tarafından English dilinden çevrildi ·
Kablolama sorun degil, okuman cok erken. No-hold modunda HTU21D, olcum bitene kadar okuma adresine NACK veriyor; analizorun gosterdigi de tam olarak bu. 12 bitlik bir nem okumasi yaklasik 16 ms’ye kadar surebilir; varsayilan cozunurluk ve biraz pay ile 15 ms’den fazla beklemek istersin. Sicaklik 50 ms ile daha yavas olan, ve buyuk ihtimalle gecikmeyi sadece nem olan bir ornekten kopyaladin ve sans eseri ters yonde kurtuldun.Tahmin yurutmek yerine yoklama yapiyorum:
Wire.beginTransmission(0x40);
Wire.write(0xF5);
Wire.endTransmission();
uint8_t n = 0;
for (int i = 0; i < 10 && n < 3; i++) {
delay(10);
n = Wire.requestFrom(0x40, 3);
}
if (n < 3) { /* skip humidity this round */ }Bir okuma yine basarisiz olursa, o dakikanin mesajindan anahtari cikar ya da null gonder. 0 gonderme; Hermetry bunu gercek bir %0 olarak kaydeder ve alarm kuralin bundan memnun olur. null sadece okuma olmadigi anlamina gelir.
Wiring is fine, your read is too early. In no-hold mode the HTU21D NACKs its read address until the measurement is done, which is exactly what the analyser shows. A 12-bit humidity reading takes up to about 16 ms, and with the default resolution and some margin you want more than 15. Temperature is the slow one at 50 ms, and you probably copied the delay from a humidity-only example and got lucky the other way round.
I poll instead of guessing:
Wire.beginTransmission(0x40);
Wire.write(0xF5);
Wire.endTransmission();
uint8_t n = 0;
for (int i = 0; i < 10 && n < 3; i++) {
delay(10);
n = Wire.requestFrom(0x40, 3);
}
if (n < 3) { /* skip humidity this round */ }And when a read still fails, leave the key out of that minute’s message or send null. Don’t send 0, Hermetry stores it as a real 0 % and your alarm rule will love that. null just means no reading.