Arduino 教程--第三十五课 Arduino 湿度传感器.doc

第三十五课 Arduino 湿度传感器在本节中，我们将学习如何使用不同的传感器连接我们的Arduino板。我们将讨论以下传感器： 湿度传感器（DHT22） 温度传感器（LM35） 水位检测传感器（简单水触发器） PIR传感器 超声波传感器 GPS湿度传感器(DHT22)DHT-22（也称为AM2302）是一个数字输出，相对湿度和温度传感器。它使用电容式湿度传感器和热敏电阻来测量周围空气，并在数据引脚上发送数字信号。在本例中，你将学习如何将此传感器与Arduino UNO一起使用。室温和湿度将打印到串口监视器上。DHT-22传感器连接很简单。左边的第一个引脚为3-5V电源，第二个引脚连接到数据输入引脚，最右边的引脚接地。技术细节 电源- 3-5V 最大电流- 2.5mA 湿度- 0-100，精确度为2-5 温度- 40至80C，精确度为0.5C必需的组件你将需要以下组件： 1 Breadboard 面包板 1 Arduino Uno R3 1 DHT22 1 10K欧姆电阻程序按照电路图连接面包板上的组件，如下图所示。草图在计算机上打开Arduino IDE软件。使用Arduino语言进行编码控制你的电路。通过单击“New”打开一个新的草图文件。Arduino代码/ Example testing sketch for various DHT humidity/temperature sensors#include DHT.h#define DHTPIN 2 / what digital pin were connected to/ Uncomment whatever type youre using!/#define DHTTYPE DHT11 / DHT 11#define DHTTYPE DHT22 / DHT 22 (AM2302), AM2321/#define DHTTYPE DHT21 / DHT 21 (AM2301)/ Connect pin 1 (on the left) of the sensor to +5V/ NOTE: If using a board with 3.3V logic like an Arduino Due connect pin 1/ to 3.3V instead of 5V!/ Connect pin 2 of the sensor to whatever your DHTPIN is/ Connect pin 4 (on the right) of the sensor to GROUND/ Connect a 10K resistor from pin 2 (data) to pin 1 (power) of the sensor/ Initialize DHT sensor./ Note that older versions of this library took an optional third parameter to/ tweak the timings for faster processors. This parameter is no longer needed/ as the current DHT reading algorithm adjusts itself to work on faster procs.DHT dht(DHTPIN, DHTTYPE);void setup() Serial.begin(9600); Serial.println(DHTxx test!); dht.begin();void loop() delay(2000); / Wait a few seconds between measurements float h = dht.readHumidity(); / Reading temperature or humidity takes about 250 milliseconds! float t = dht.readTemperature(); / Read temperature as Celsius (the default) float f = dht.readTemperature(true); / Read temperature as Fahrenheit (isFahrenheit = true) / Check if any reads failed and exit early (to try again). if (isnan(h) | isnan(t) | isnan(f) Serial.println(Failed to read from DHT sensor!); return; / Compute heat index in Fahrenheit (the default) float hif = puteHeatIndex(f, h); / Compute heat index in Celsius (isFahreheit = false) float hic = puteHeatIndex(t, h, false); Serial.print (Humidity: ); Serial.print (h); Serial.print ( %t); Serial.print (Temperature: ); Serial.print (t); Serial.print ( *C ); Serial.print (f); Serial.print ( *Ft); Serial.print (Heat index: ); Serial.print (hic); Serial.print ( *C ); Serial.print (hif); Serial.println ( *F);代码说明DHT22传感器具有四个端子连接到电路板的端子（Vcc，DATA，NC，GND），如下： DATA引脚连接到Arduino的2号引脚号 Vcc引脚连接到