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Interfacing DHT11 and DHT22 Sensors with Arduino

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24
Dec

Interfacing DHT11 and DHT22 Sensors with Arduino

 

All objects, including the human body, emit heat energy in the form of infrared radiation when their temperature is above absolute zero (0 Kelvin or -273.15 °C). This phenomenon is a result of the thermal motion of particles within the object. The hotter an object is, the more infrared radiation it emits. However, this radiation is not visible to the naked eye because it falls within the infrared spectrum, which lies just beyond the visible light range.

PIR (Passive Infrared) sensors are specifically designed to detect this infrared radiation. They can sense the heat emitted by objects in their vicinity, allowing them to detect motion based on changes in infrared energy. When a warm object, such as a human body, enters the sensor’s detection range, it causes a change in the amount of infrared radiation hitting the sensor. This change is what the PIR sensor detects and interprets as movement.

DHT11 vs DHT22

The DHT11 and DHT22 are two of the most commonly used sensors in the DHTxx series, widely favored for their simplicity and ease of integration into various projects. While these sensors look similar and share the same pinout, their specifications differ significantly, making them suitable for different use cases.

Among the two, the DHT22 is the more expensive option, but it undoubtedly offers superior performance. The DHT22 can measure temperatures in a wider range, from -40°C to +125°C, with an impressive accuracy of ±0.5°C. In contrast, the DHT11 is limited to measuring temperatures from 0°C to 50°C and has a much lower accuracy of ±2°C. This makes the DHT22 more versatile for applications that require higher temperature ranges and precise readings.

When it comes to humidity measurement, the DHT22 also outperforms the DHT11. The DHT22 can measure relative humidity from 0% to 100% with an accuracy of 2-5%, making it suitable for a wide range of environments. On the other hand, the DHT11 can only measure humidity between 20% and 80%, with a higher margin of error (±5%), limiting its usefulness in extreme humidity conditions.

Overall, the DHT22 is ideal for projects that require broader environmental monitoring and greater accuracy, such as weather stations, industrial applications, and scientific experiments. The DHT11, while more affordable, is best suited for simpler applications where precise readings are not as critical, such as basic temperature and humidity logging.

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