ESP8266 Community Forum

- Thu Mar 17, 2016 4:32 pm #43435 for me it worked to set the DHTPIN to OUTPUT and LOW before going to sleep:

Code: Select allpinMode(DHTPIN, OUTPUT);
digitalWrite(DHTPIN, LOW);
ESP.deepSleep(0.1 * 60000000); // Send to sleep for 35 minutes


- Mon Mar 11, 2019 4:39 pm #81049 I have exactly the same problem.
My ESP board comes out of deep sleep, but then I can't read DHT22 values any longer.

If I remove the DHT22 from the breadboard and plug it back in, it reads a value.
What is the solution?

I have:

NodeMCU v3 Lolin

DHT22 sensor

D0 is connected to RST

DHT22 is connected to D4

Parts of code:

Code: Select all#define DHTTYPE DHT22
uint8_t DHTPIN = D4;

void setup() {
  // this code will only run once
  Serial.begin(115200);

  Serial.println(F("Setting up DHT..."));
  pinMode(DHTPIN, INPUT);
  dht.begin();

  // set up wifi
  delay(100); // doesn't work if we go straight to WiFi setup...
  Serial.println(F("Setting up Wifi"));
  WiFi.begin(ssid, password);
  connect_wifi();
...
}
void connect_wifi() {
...
}
void loop() {
  int i; 

  if (WiFi.status() != WL_CONNECTED) {
    Serial.println(F("Wifi: disconnected -> reconnecting"));
    connect_wifi();   
  }
  client.loop();

 for (i=0; i<20; i++) {
    temperatureC = dht.readTemperature();
    Serial.print(F("Temperature: ")); Serial.println(temperatureC);
    publish_mqtt(mqtt_temp_topic, temperatureC);
 
    humidity = dht.readHumidity();
    Serial.print(F("Humidity: ")); Serial.println(humidity);
    publish_mqtt(mqtt_humidity_topic, humidity);
    delay((i+1)*1000);
    if (isnan(temperatureC)) {
       client.publish(mqtt_debug_topic, "impossible de relever la temperature via DHT22");
    } else {
       break;
    }
  }
 
  // disconnect & sleep
  client.disconnect();
  WiFi.disconnect();
  delay(100);
  Serial.println(F("Entering deep sleep for 60 seconds"));
  ESP.deepSleep(60 * 1000000, WAKE_RF_DEFAULT);
  delay(1000);
  Serial.println(F("Init DHT")); // tried this
  dht.begin();
}



Thanks