[NUCLEO-L552ZE Review] + IoT Application Development: Driving Temperature and Humidity Sensor DHT22

dql2016

[NUCLEO-L552ZE Review] + IoT Application Development: Driving Temperature and Humidity Sensor DHT22 [Copy link]

DHT22 (AM2302) is a calibrated digital temperature and humidity sensor used to detect ambient temperature and humidity, with a standard single bus
interface. It has higher accuracy and a larger range than DHT11.

The real thing is as follows:

The basic parameters of DHT22 are as follows:

Interface description:
VCC: connect to 3.3V ~ 5.5V
GND: connect to GND
DOUT: connect to MCU IO

The AM2302 device uses a simplified single bus communication. A single bus has only one data line, and the data exchange and control in the system are all
completed by the data line. A single bus usually requires an external pull-up resistor of about 5.1kΩ, so that when the bus is idle, its state is
high. SDA is used for communication and synchronization between the microprocessor and AM2302. It uses a single bus data format and transmits 40
bits of data at a time, with the high bit first. Therefore, only one GPIO of NUCLEO-L552ZE is needed to drive it, and PG1 is used here.

Add the driver code to the project, where the temperature and humidity values are printed every 1 second:

The results are as follows:

Test project:

stm32l552zet6qu_test.7z (6.49 MB, downloads: 17)

2020-12-26 18:08 上传

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DHT22 related information:

DHT22-Temperature-Humidity-Sensor-UserManual.pdf (707.75 KB, downloads: 2)

2020-12-26 18:08 上传

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AM2302_V1.1.pdf (865.45 KB, downloads: 4)

2020-12-26 18:08 上传

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jinglixixi

Thanks for sharing

okhxyyo

ST new product NUCLEO-L552ZE-Q (Cortex-M33)

Summary post: https://bbs.eeworld.com.cn/thread-1152571-1-1.html

dql2016

jinglixixi posted on 2020-12-27 20:42 Relationship sharing