DHT22 - 温度和湿度传感器

2018年4月19日 - 0 Comments

DHT22 Temperature Sensor Module

DHT22 Sensor Pinout

针识别和配置

No:	Pin Name	Description
For DHT22 Sensor
1	Vcc	Power supply 3.5V to 5.5V
2	数据	Outputs both Temperature and Humidity through serial Data
3	NC	No Connection and hence not used
4	Ground	Connected to the ground of the circuit
For DHT22 Module
1	Vcc	Power supply 3.5V to 5.5V
2	数据	Outputs both Temperature and Humidity through serial Data
3	Ground	Connected to the ground of the circuit

DHT22规范

Operating Voltage: 3.5V to 5.5V
Operating current: 0.3mA (measuring) 60uA (standby)
输出：串行数据
温度范围：-40°C至80°C
Humidity Range: 0% to 100%
Resolution: Temperature and Humidity both are 16-bit
Accuracy: ±0.5°C and ±1%

注意：DHT22 Datasheet.can be found at the bottom of the page

DHT22 Equivalent Temperature Sensors

DHT11，am2302，sht71

Other Temperature Sensors

Thermocouple, TMP100,LM75, DS18820, SHT15,LM35DZ, TPA81, D6T

Difference between DHT22 Sensor and Module

The DHT22 sensor is the successor of theDHT11模块, it can either be purchased as a sensor or as a module. Either way the performance of the sensor is same. The sensor will come as a 4-pin package out of which only three pin will be used whereas the module will come with just three pins as shown in theDHT22引脚声above.

传感器和模块之间的唯一区别在于模块将具有滤波电容和内置电阻器，并且如果需要，您必须在外部使用它们。

The module is slightly costly than the DHT11, but it has a higher measuring range and slightly better accuracy .

Where DHT22 Sensor is Used

TheDHT22is a commonly used Temperature and humidity sensor. The sensor comes with a dedicatedNTCto measure temperature and an 8-bit microcontroller to output the values of temperature and humidity as serial data. The sensor is also factory calibrated and hence easy to interface with other microcontrollers.

The sensor can measure temperature from-40°C to 80°Cand humidity from0% to 100%with an accuracy of ±1°C and ±1%. So if you are looking to measure in this range then this sensor might be the right choice for you.

How to use DHT22 Sensor

TheDHT22 Sensoris factory calibrated and outputs serial data and hence it is highly easy to set it up. The connection diagram for this sensor is shown below.

DHT22 Microcontroller Interfacing Circuit Diagram

As you can see the data pin is connected to an I/O pin of the MCU and a 5K pull up resistor is used. This data pin outputs the value of both temperature and humidity as serial data. If you are trying to接口DHT22与Arduino Unothen there are ready made libraries for it which will give you a quick start.

If you are trying to interface it with some other MCU then the datasheet given below will come in handy. The output given out by the data pin will be in the order of 8bit humidity integer data + 8bit the Humidity decimal data +8 bit temperature integer data + 8bit fractional temperature data +8 bit parity bit. To request the DHT11 module to send these data the I/O pin has to be momentarily made low and then held high as shown in the timing diagram below.

DHT22 Timing Diagram