{"id":5378,"date":"2019-04-25T11:11:14","date_gmt":"2019-04-25T11:11:14","guid":{"rendered":"http:\/\/randomnerdtutorials.com\/?p=5378"},"modified":"2019-04-25T13:34:48","modified_gmt":"2019-04-25T13:34:48","slug":"complete-guide-for-dht11dht22-humidity-and-temperature-sensor-with-arduino","status":"publish","type":"post","link":"https:\/\/randomnerdtutorials.com\/complete-guide-for-dht11dht22-humidity-and-temperature-sensor-with-arduino\/","title":{"rendered":"Complete Guide for DHT11\/DHT22 Humidity and Temperature Sensor With Arduino"},"content":{"rendered":"\n

This article is a guide for the popular DHT11 and DHT22 temperature and humidity sensors with the Arduino. We\u2019ll explain how it works, show some of its features and share an Arduino project example that you can modify to use in your own projects.<\/p>\n\n\n\n

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For more guides about other popular sensors, check our compilation of more than 60 Arduino tutorials and projects: 60+ Arduino Projects and Tutorials<\/a><\/strong>.<\/p>\n\n\n\n

Introducing the DHT11 and DHT22 Sensors<\/h2>\n\n\n\n

The DHT11 and DHT22 sensors are used to measure temperature and relative humidity. These are very popular among makers and electronics hobbyists.<\/p>\n\n\n\n

\"DHT11\/DHT22<\/figure><\/div>\n\n\n\n

These sensors contain a chip that does analog to digital conversion and spit out a digital signal with the temperature and humidity. This makes them very easy to use with any microcontroller.<\/p>\n\n\n\n

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DHT11 vs DHT22<\/h3>\n\n\n\n

The DHT11 and DHT22 are very similar, but differ in their specifications. The following table compares some of the most important specifications of the DHT11 and DHT22 temperature and humidity sensors. For a more in-depth analysis of these sensors, please check the sensors’ datasheet. <\/p>\n\n\n\n
<\/td>
DHT11<\/strong><\/span><\/center><\/td>
DHT22<\/strong><\/span><\/center><\/td><\/tr>
<\/td>
\"\"<\/center><\/td>
\"\"<\/center><\/td><\/tr>
Temperature range<\/strong><\/td>0 to 50 \u00baC +\/-2 \u00baC<\/sup><\/td>-40 to 80 \u00baC +\/-0.5\u00baC<\/sup><\/td><\/tr>
Humidity range<\/strong><\/td>20 to 90% +\/-5%<\/sup><\/td>0 to 100% +\/-2%<\/sup><\/td><\/tr>
Resolution<\/strong><\/td>Humidity: 1%
Temperature: 1\u00baC <\/td>		Humidity: 0.1%
Temperature: 0.1\u00baC<\/td><\/tr>
Operating voltage<\/strong><\/td>3 – 5.5 V DC<\/td>3 – 6 V DC <\/td><\/tr>
Current supply<\/strong><\/td>0.5 – 2.5 mA<\/td>1 – 1.5 mA<\/td><\/tr>
Sampling period<\/strong><\/td>1 second<\/td>2 seconds<\/td><\/tr>
Price<\/strong><\/td>$1 to $5<\/td>$4 to $10<\/td><\/tr>
Where to buy<\/strong><\/td>Check prices<\/a><\/td>Check prices<\/a><\/td><\/tr><\/tbody><\/table>\n\n\n\n

The DHT22 sensor has a better resolution and a wider temperature and humidity measurement range. However, it is a bit more expensive, and you can only request readings with 2 seconds interval. <\/p>\n\n\n\n

The DHT11 has a smaller range and it’s less accurate. However, you can request sensor readings every second. It’s also a bit cheaper. <\/p>\n\n\n\n

Despite their differences, they work in a similar way, and you can use the same code to read temperature and humidity. You just need to select in the code the sensor type you’re using.<\/p>\n\n\n\n

DHT Pinout<\/h2>\n\n\n\n

DHT sensors have four pins as shown in the following figure. However, if you get your DHT sensor in a breakout board, it comes with only three pins and with an internal pull-up resistor on pin 2.<\/p>\n\n\n\n

\"DHT22<\/figure><\/div>\n\n\n\n

The following table shows the DHT22 and DHT11 pinout. When the sensor is facing you, pin numbering starts at 1 from left to right<\/p>\n\n\n\n
DHT pin<\/strong><\/td>Connect to<\/strong><\/td><\/tr>
1<\/strong><\/td>5V<\/span><\/td><\/tr>
2<\/strong><\/td>Any digital GPIO; also connect a 10k Ohm pull-up resistor<\/td><\/tr>
3<\/strong><\/td>Don’t connect<\/td><\/tr>
4<\/strong><\/td>GND<\/span><\/td><\/tr><\/tbody><\/table>\n\n\n\n

Where to buy?<\/h3>\n\n\n\n

You can check Maker Advisor Tools<\/a>‘ page and find the best price for these modules:<\/p>\n\n\n\n