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

Arduino 湿度传感器

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80°C,精确度为±0.5°C

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。

Arduino 湿度传感器

Arduino 湿度传感器

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 湿度传感器

Arduino代码

// Example testing sketch for various DHT humidity/temperature sensors 
#include "

DHT.h"

#define DHTPIN 2 // what digital pin we're connected to // Uncomment whatever type you're 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 = dht.computeHeatIndex(f, h);

   // Compute heat index in Celsius (isFahreheit = false)
   float hic = dht.computeHeatIndex(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Arduino板的5伏电压
  • GND引脚连接到Arduino板的接地
  • 我们需要在DATA和Vcc引脚之间连接10k欧姆电阻(上拉电阻)

一旦硬件连接完成,你需要添加DHT22库到你的Arduino库文件,如前所述。

结果

你将看到串口监视器上的温度和湿度显示,每2秒更新一次。