arduino dht22 datasheet - DHT22 output calibrated digital signal. It utilizes exclusive digital-signal-collecting-technique and humidity sensing technology, assuring its reliability and stability.
Its sensing elements is connected with 8-bit single-chip computer. Every sensor of this model is temperature compensated and calibrated in accurate calibration chamber and the calibration-coefficient is saved in type of programme in OTP memory, when the sensor is detecting, it will cite coefficient from memory.
Small size & low consumption & long transmission distance (20m) enable arduino DHT22 to be suited in all kinds of harsh application occasions. Single-row packaged with four pins, making the connection very convenient.
Power's voltage should be 3.3-6V DC. When power is supplied to sensor, don't send any instruction to the sensor within one second to pass unstable status. One capacitor valued 100nF can be added between VDD and GND forwave filtering.
(2) Communication and signal
Single-bus data is used for communication between MCU and DHT22, it costs 5mS for single time communication.
Data is comprised of integral and decimal part, the following is the formula for data. DHT22 send out higher data bit firstly! DATA=8 bit integral RH data+8 bit decimal RH data+8 bit integral T data+8 bit decimal T data+8 bit check-sumIf the data transmission is right, check-sum should be the last 8 bit of "8 bit integral RH data+8 bit decimal RHdata+8 bit integral T data+8 bit decimal T data".
When MCU send start signal, DHT22 change from low-power-consumption-mode to running-mode.
When MCU finishs sending the start signal, DHT22 will send response signal of 40-bit data that reflect the relative humidity and temperature information to MCU.
Without start signal from MCU, DHT22 will not give response signal to MCU. One start signal for one time's response data that reflect the relative humidity and temperature informationfrom DHT22. DHT22 will change to low-power-consumption-mode when data collecting finish if it don't receive start signal from MCU again.
For more detail information you can download arduino DHT22 / AM2302 sensor datasheet here.
Its sensing elements is connected with 8-bit single-chip computer. Every sensor of this model is temperature compensated and calibrated in accurate calibration chamber and the calibration-coefficient is saved in type of programme in OTP memory, when the sensor is detecting, it will cite coefficient from memory.
Small size & low consumption & long transmission distance (20m) enable arduino DHT22 to be suited in all kinds of harsh application occasions. Single-row packaged with four pins, making the connection very convenient.
DHT22 Feature & Application:
- 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
DHT22 Operating specifications:
(1) Power and PinsPower's voltage should be 3.3-6V DC. When power is supplied to sensor, don't send any instruction to the sensor within one second to pass unstable status. One capacitor valued 100nF can be added between VDD and GND forwave filtering.
(2) Communication and signal
Single-bus data is used for communication between MCU and DHT22, it costs 5mS for single time communication.
Data is comprised of integral and decimal part, the following is the formula for data. DHT22 send out higher data bit firstly! DATA=8 bit integral RH data+8 bit decimal RH data+8 bit integral T data+8 bit decimal T data+8 bit check-sumIf the data transmission is right, check-sum should be the last 8 bit of "8 bit integral RH data+8 bit decimal RHdata+8 bit integral T data+8 bit decimal T data".
When MCU send start signal, DHT22 change from low-power-consumption-mode to running-mode.
When MCU finishs sending the start signal, DHT22 will send response signal of 40-bit data that reflect the relative humidity and temperature information to MCU.
Without start signal from MCU, DHT22 will not give response signal to MCU. One start signal for one time's response data that reflect the relative humidity and temperature informationfrom DHT22. DHT22 will change to low-power-consumption-mode when data collecting finish if it don't receive start signal from MCU again.
DHT22 Temperature and Humidity Sensor: Is The Pull-up Resistor Necessary?
For more detail information you can download arduino DHT22 / AM2302 sensor datasheet here.
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