`capteur-dht.ino`

Particle Photon · File : capteur-dht.ino · Language : Arduino · Use case : Lire un DHT11 et publier température/humidité toutes les 30 s

The DHT11 sensor delivers temperature and humidity, published to the cloud every 30 s as a private event. The pace respects the Particle rate limit and the battery; the JSON fits in 64 bytes.

Hardware

A Particle Photon module (2.4 GHz Wi-Fi, STM32 microcontroller, metal shielding) powered by USB or VIN. 1 DHT11 sensor (3-pin module) + 10 kΩ resistor for bare sensors.

Wiring

VDD to 3V3, GND to GND, DATA to D5 with a 10 kΩ pull-up to 3V3.

How it works

The Adafruit library drives the 1-wire protocol; the reading is formatted as JSON then Particle.publish uploads it as a private event (visible to your account only).

Running it

With the Particle CLI: particle flash --serial (DFU mode, double reset) or OTA flash once the board is online. Safe Mode (reset + WiFi) covers troubleshooting.

Variants

Move to DHT22 for ±0.5 °C, or buffer locally (SaveToSparkFile/SF25) when the cloud is unreachable.

capteur-dht.ino

// DHT11 sur D5 + publication periodique vers le cloud.
// Bibliotheque : "DHT sensor library" (Adafruit) via Particle Build.
#include "DHT.h"

#define TYPE_DHT DHT11
DHT dht(D5, TYPE_DHT);

unsigned long dernierePublication = 0;
const unsigned long PERIODE = 30000; // 30 s : menage la limite cloud

void setup() {
  Serial.begin(9600);
  dht.begin();
}

void loop() {
  if (millis() - dernierePublication < PERIODE) return;
  dernierePublication = millis();

  float h = dht.readHumidity();
  float t = dht.readTemperature();
  if (isnan(h) || isnan(t)) {
    Serial.println(F("lecture DHT ratee"));
    return;
  }

  char trame[64];
  snprintf(trame, sizeof(trame),
           "{\"t\":%.1f,\"h\":%.1f}", t, h);
  Particle.publish("mesures", trame, 60, PRIVATE);
  Serial.println(trame);
}

// getTemperature() (API systeme) donne aussi la temperature du MCU.

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