Comments on: Complete Guide for DHT11/DHT22 Humidity and Temperature Sensor With Arduino

By: Boris Levitan

Boris Levitan — Mon, 28 Mar 2022 17:33:50 +0000

The problem I’ve get was an unstable operation. The sketch loop block internally interrupted and operation started with printing DHTxx test! . That happened sporadically more or less frequently, sometimes normal reading doesn’t working, just a few lines printing with DHTxx test!.
In my case the problem solved with adding small delays between sensor reading statements:
void loop() {
// Wait a few seconds between measurements.
delay(2000);

// Reading temperature or humidity takes about 250 milliseconds!
// Sensor readings may also be up to 2 seconds ‘old’ (its a very slow sensor)
Serial.print(F(“Start to read: “));
float h = dht.readHumidity(); Serial.print(F(” h, “));
delay(250); // making readings form the sensor more sparce
// Read temperature as Celsius (the default)
float t = dht.readTemperature(); Serial.print(F(” t, “));
delay(250); // making readings form the sensor more sparce
// Read temperature as Fahrenheit (isFahrenheit = true)
float f = dht.readTemperature(true); Serial.print(F(” f “));
delay(250); // making readings form the sensor more sparce
// Check if any reads failed and exit early (to try again).
if (isnan(h) || isnan(t) || isnan(f)) {
Serial.println(F(“Failed to read from DHT sensor!”));
return;
}
//}

// Compute heat index in Fahrenheit (the default)
float hif = dht.computeHeatIndex(f, h); Serial.print(F(” Calculate hiV “));
// Compute heat index in Celsius (isFahreheit = false)
float hic = dht.computeHeatIndex(t, h, false); Serial.print(F(” Calculate hiC “));
delay(1000); Serial.println(F(” Ready to print “));
//Serial.println(F(“all are ready”));
Serial.print(F(“Humidity: “));
Serial.print(h);
Serial.print(F(“% Temperature: “));
Serial.print(t);
Serial.print(F(“°C “));
Serial.print(f);
Serial.print(F(“°F Heat index: “));
Serial.print(hic);
Serial.print(F(“°C “));
Serial.print(hif);
Serial.println(F(“°F”));
}

One more unstable issue is delay() method operation. From time to time it starts to work with falce delay interval much less than requested by parameter of the method. Usually it turns into normal opreation after a few minutes ubnormality.

By: vilasrao

vilasrao — Sat, 08 Feb 2020 09:42:41 +0000

Well ! Best tutorial !

By: Sara Santos

Sara Santos — Sat, 27 Apr 2019 10:08:43 +0000

In reply to yuvraj agarwal.

Hi.
We have this tutorial that may help. https://randomnerdtutorials.com/arduino-temperature-displayed-on-4-digit-7-segment/
Please note that this tutorial is a few years old. I’m not sure if it is still working.
Regards,
Sara

By: yuvraj agarwal

yuvraj agarwal — Sat, 27 Apr 2019 05:58:13 +0000

How do i show the temperature on a 3 digit seven segment display?PLEASE!?

By: Sara Santos

Sara Santos — Sun, 03 Mar 2019 17:48:38 +0000

In reply to Al.

Hi Al.
Please check that the sensor is being properly powered (5V to the Vin pin of the sensor).
Regards,
Sara

By: Al

Al — Sat, 02 Mar 2019 22:33:41 +0000

I have tried this method and several other libraries. I hoping this would be the one that worked. But still no go. I can hook up the DHT22 to my Arduino UNO and it reads Temp/Humidity just fine, but I cannot get the ESP8266-01 to read data. I get the “Failed to read from DHT sensor.” Any thoughts on why it works on the UNO but not on the EP8266? Thank you!

By: Sara Santos

Sara Santos — Thu, 04 Oct 2018 15:47:48 +0000

In reply to zikry.

Hi.
Yes! Here’s the tutorial:
https://randomnerdtutorials.com/esp32-dht11-dht22-temperature-humidity-web-server-arduino-ide/
Regards,
Sara 🙂

By: zikry

zikry — Wed, 03 Oct 2018 13:40:17 +0000

do you have any tutorial on how to connect to esp32 with DHT11, because i’m really new to this. I really need your help

By: Sara Santos

Sara Santos — Fri, 31 Aug 2018 08:58:31 +0000

In reply to Ralph Hulslander.

Hi.
You can use an ethernet shield connected to the Arduino.
Or you may consider using an ESP8266 or an ESP32. Take a look at the following tutorials that might help you:
– https://randomnerdtutorials.com/esp8266-dht11dht22-temperature-and-humidity-web-server-with-arduino-ide/
– https://randomnerdtutorials.com/esp32-dht11-dht22-temperature-humidity-web-server-arduino-ide/
I hope this helps.
Regards,
Sara 🙂

By: Sara Santos

Sara Santos — Fri, 31 Aug 2018 08:52:03 +0000

In reply to Kara.

Hi Kara.
It seems that you also need to install the Adafruit_Sensor library.
Here’s the link for that library:
https://github.com/adafruit/Adafruit_Sensor
I hope this helps.
Regards,
Sara 🙂