📅  最后修改于: 2020-11-05 03:41:37             🧑  作者: Mango
在本节中,我们将学习如何将Arduino开发板与不同的传感器接口。我们将讨论以下传感器-
DHT-22(也称为AM2302)是数字输出,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的空气,并在数据引脚上发送数字信号。
在此示例中,您将学习如何将此传感器与Arduino UNO一起使用。室温和湿度将被打印到串行监视器上。
连接很简单。左边的第一个引脚为3-5V电源,第二个引脚为数据输入引脚,最右边的引脚接地。
电源-3-5V
最大电流-2.5mA
湿度-0-100%,精度2-5%
温度-40至80°C,±0.5°C精度
您将需要以下组件-
遵循电路图,并连接面包板上的组件,如下图所示。
打开计算机上的Arduino IDE软件。使用Arduino语言进行编码将控制您的电路。通过单击“新建”打开一个新的草图文件。
// 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 (" *F\t");
Serial.print ("Heat index: ");
Serial.print (hic);
Serial.print (" *C ");
Serial.print (hif);
Serial.println (" *F");
}
DHT22传感器具有四个端子(V cc ,DATA,NC,GND),它们按如下方式连接至电路板:
硬件连接完成后,您需要如前所述将DHT22库添加到Arduino库文件中。
您将在串口监视器上看到温度和湿度显示,该显示每2秒更新一次。