ABSTRACT
This design is the use of MSC-51 Series MCU AT89S51 and DHT11 in the
low-cost temperature and humidity detection system. This design includes the design
of hardware and system software design. Hardware circuit includes a microcontroller,
temperature and humidity sensors, display module, the alarm and the keyboard 5, the
DHT11 temperature and humidity sensor and 1602 constitute a system of character
LCD module display module, the system circuit is simple, stable, high integration,
commissioning Convenient, high precision, has some practical value. Temperature
and humidity control circuit in which the temperature and humidity sensors and
compare the value of the preset temperature alarm circuit, the user input required
pre-default value, when the actual temperature and humidity measurements of
temperature and humidity is greater than the preset value, an alarm signal (bee Buzzer
beep). Software part includes the main program, display routines, subroutines side
temperature and humidity
The design uses the DHT11 temperature and humidity sensors is a digital output
with a calibrated temperature and humidity combined sensor, the sensor includes a
resistance and a sense of the original wet NTC temperature measurement devices, and
with a high-performance 8-bit microcontroller connected. Therefore, the product has
excellent quality, fast response, anti-interference ability, high cost and other
advantages. AT89S51 is a low consumption of item-level, high-performance CMOS8
bit microcontroller, because of its powerful features and low price, so use it in many
fields.
【Key words】
Temperature measurement Humidity measurement AT89S51 DHT11
