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DHT22 Humidity and Temperature Sensor
The DHT22 Sensor Module is a basic, low-cost digital temperature and humidity sensor. It uses a capacitive humidity sensor and a thermistor to measure the surrounding air and spits out a digital signal on the data pin (no analog input pins are needed). It's fairly simple to use but requires careful timing to grab data. The only real downside of this sensor is you can only get new data from it once every 2 seconds, so when using our library, sensor readings can be up to 2 seconds old.
Simply connect the first pin on the left to 3-5v power, the second pin to your data input pin, and the rightmost pin to the ground. Although it uses a single wire to send data it is not Dallas One wire compatible if you want multiple sensors, each one must have its own data pin feature & application: High precision capacitive type full range temperature compensated relative humidity and temperature measurement calibrated digital signal outstanding long-term stability extra components not needed long transmission distance low power consumption 4 pins packaged and fully interchangeable.
- Testing and inspection equipment
- Consumer goods
- Automotive automation
- Data loggers
- Weather stations
- Home appliances
- Humidity control
- 1 x DHT22 Temperature Sensor
DHT22 Temperature Sensor Specifications
|Measuring range Temperature||-40 to 80 ℃|
|Measuring Range Humidity||0 to 99.9%RH|
|Resolution Temperature||0.1 ℃|
|Dimensions||3 x 2 x 1 cms|
1. What is DHT22? How to set up the DHT22 Temperature sensor?
- The DHT22 Digital Temperature and Humidity Sensor Module AM2302 is a basic, low-cost digital temperature and humidity sensor. It uses a capacitive humidity sensor and a thermistor to measure the surrounding air and spits out a digital signal on the data pin
Simply connect the first pin on the left to 3-5V power, the second pin to your data input pin and the rightmost pin to ground. Although it uses a single-wire to send data it is not Dallas One Wire compatible! If you want multiple sensors, each one must have its own data pin.
2. What is difference between DHT11 and DHT22 sensors?
- Both units use a capacitive humidity sensor and a thermistor to measure the surrounding air, and output a digital signal on the data pin (no analog input pins needed), to be easily read by a microcontroller. They are basic and slow, but great for small scale projects that require basic data logging.
The DHT11 is less precise, works in a smaller range of temperature/humidity, and is slightly slower, but also features a lower price point and a smaller form factor. If accuracy is important for your project, and you don't mind the higher price, go for the DHT22. Otherwise, the DHT11 should be good enough
3. What is the working principle of DHT22 Sensor?
- DHT22 sensor consists of a capacitive humidity sensing element and a thermistor for sensing temperature. The humidity sensing capacitor has two electrodes with a moisture holding substrate as a dielectric between them. Change in the capacitance value occurs with the change in humidity levels. The IC measure, process this changed resistance values and change them into digital form.
For measuring temperature this sensor uses a Negative Temperature coefficient thermistor, which causes a decrease in its resistance value with increase in temperature. To get larger resistance value even for the smallest change in temperature, this sensor is usually made up of semiconductor ceramics or polymers.
4. Does the DHT22 module need a resistor?
- DHT22 4 pin module itself requires an external pull up resistor for it to function correctly. But DHT22 is also available on PCB which will have its own pull up resistor, thus forgoing the need for the user to add a pull up resistor.
5. Are DHT11 and DHT22 interchangeable?
- Both the DHT-11 and DHT-22 are temperature and humidity sensors. The two options are fully interchangeable. the main differences between the two are accuracy, measuring range, and price.
6. How does the humidity and temperature sensor perform?
- The humidity sensor in DHT22 is a capacitive humidity sensor. It works based on the varying capacitance at different humidity level.
For temperature, the DHT22 sensor houses a thermistor. It is able to deduce the ambient temperature based on the variation of resistance due to surrounding temperature.