DHT21/AM2301 capacitive digital temperature and humidity sensor, alternative SHT10 SHT11
1). The relative humidity and temperature measurement, calibration, all digital output
2.) excellent long-term stability
3). No additional components
4). Long distance signal transmission
5) low energy consumption
6). 4 pin installation
7.) fully interchangeable
AM2301 description of products:
AM2301 digital temperature and humidity sensor is a contains a composite of the temperature and humidity sensor has been calibrated digital signal output. It dedicated digital module acquisition technology and the temperature and humidity sensor technology, ensure that the product has a very high reliability and excellent long-term stability.
Sensor includes a capacitive moisture element and a DS18B20 temperature measuring device, and connected to a high-performance 8-bit microcontroller. So the product has excellent quality, super fast response, strong anti-jamming capability, very high cost performance advantages.
Every AM2301 sensor calibration in the extremely precise humidity calibration laboratory. Calibration coefficient in the form of a program stored in the OTP memory, inside the sensor in detecting signal processing process to invoke these calibration coefficient. Single wire serial interface, the system integration becomes simple and fast. Ultra small volume, low power consumption, the signal transmission distance of 20 meters, making it a all kinds of optimal choice of even the most demanding applications, product lead for the three core shielded wire.
Areas of application:
1) hvac 2) test and inspection equipment
3) auto 4) data recorder
5) 6) automatic control of consumer goods
7) weather station 8) household appliances
9) the humidity regulator 10) medical care
Model measurement range of temperature measurement range resolution in humidity measurement precision, temperature measurement precision
AM2301 0-100% RH - 40 ~ 80 °C to + / - 3% RH + 0.5 0.1 °C
Compatibility can be completely interchangeable
Long-term stability of + / - 0.3% RH/year
Power supply pin:
AM2301 power supply voltage is 3.3 to 6 v. Sensor after power on, wait for 1 s to cross the unstable state, during this period do not need to send any instructions. Power supply pins (VDD and GND) can increase a 100 nf capacitance between to decoupling filtering.
Single bus interface:
Single bus data for communication between microprocessor and AM2301 and synchronization, a communication time about 5 ms, specific format in the following illustration, the current data of 40 bits, high in first out.
Data format: 40 bit data = 16 + 16 bit humidity data bit temperature data + 8 bits checksum
Example: receive 40 bit data are as follows:
0000 0010 1000 1100 0000 0001 0101 1111 1110 0001
Humidity, temperature data validation and data
Checksum = (low humidity high 8 + 8 + 8 + high temperature to low temperature 8) of the sum of 8, for example: at the end of the checksum = 0000 + 0010 + 1000 1000 0010 0001 0001 + 0101 = 1110, 1110
This case humidity = 65.2% RH, humidity value calculation method: put the humidity data from binary get 652 0000 0010 1000 0000 is converted to a decimal, humidity = 652/10 = 65.2% RH. The calculation method of temperature and humidity values are the same, so this case = 35.1 °C temperature.
When the temperature is lower than 0 °C temperature data of the highest position 1.
For example: 10.1 °C for 1000, 0000, 0110, 0101
User host (MCU) to send a start signal, AM2301 from low power mode switch to high speed mode, after waiting for the start of the host signal, AM2301 to send response signal, sent 40 bits of data, and triggers a signal acquisition.
(note: the host from AM2301 reading of temperature and humidity data is always the last measurements, such as measuring two intervals of time is very long, please read two consecutive times for real-time temperature and humidity value)
AM2301/DHT21 Product Overview
Is a AM2301/DHT21 digital temperature and humidity sensor with a calibrated digital signal output of the temperature and humidity combined sensor. Application-specific digital module acquisition technology and the temperature and humidity sensing technology, to ensure that products with high reliability and excellent long-term stability. The sensor includes a capacitive humidity sensitive element and a NTC temperature measurement devices, and connected with a high-performance 8-bit microcontroller. The product has excellent quality, fast response, anti-interference ability, cost and other advantages. Each AM2301/DHT21 sensors are extremely accurate humidity calibration chamber for calibration. Calibration coefficients stored in the form of a program in OTP memory, internal sensor detection signal processing to call these calibration coefficients. The single wire serial interface, the system integration becomes simpler and quicker. The ultra-small size, low power consumption, signal transmission distance up to 20 meters, it is the best choice for a variety of applications and even the most demanding applications. The product is a 4-pin single row pin package. Convenient connection Special packages can be provided according to user needs.
Of HVAC tests and testing equipment
Automotive data loggers
Automatic control of consumer goods
Weather station appliances