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5-2 修改電路1_改成較穩定的電路

5-4 修改電路3_加裝4個LED標示燈 next

pm2.5空氣品質感測器製作研習
================

需要材料：

DHT22溫濕度感測器 \* 1

10k OM 電阻 \* 1

長杜邦線 \* 1 (資料傳輸 黃線)

麵包板跳線 \* 1 (電源 紅線)

ps：DHT22電源 接地先不接！再下一步驟會跟LED燈一起接。

![](http://maker.tn.edu.tw/uploads/tad_book3/image/SharpGP2Y1010_ESP8266_DHT22_s_bb.png)

DHT22的程式庫需另外下載安裝，請在Arduino IDE程式的\[草稿碼\]→\[匯入程式庫\]→\[管理程式庫...\]

![](http://maker.tn.edu.tw/uploads/tad_book3/image/2016-07-19_220346.png)

搜尋DHT22，\[選擇版本\] 點選最新版本，按 \[安裝\]

![](http://maker.tn.edu.tw/uploads/tad_book3/image/2016-07-19_220803.png)

測試程式

![](http://maker.tn.edu.tw/uploads/tad_book3/image/2016-07-22_125346.png)

修改程式：

<span style="color:#FF0000;">\#define DHTPIN 7 // 研習使用Arduino Digital 7，請修改為7</span>

![](http://maker.tn.edu.tw/uploads/tad_book3/image/2016-07-22_125402.png)

程式庫提供的範例 DHTtester

```

// Example testing sketch for various DHT humidity/temperature sensors
// Written by ladyada, public domain
#include "DHT.h"
#define DHTPIN 7     // 研習使用Arduino Digital 7，請修改為7
// 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() {
// Wait a few seconds between measurements.
delay(2000);
// Reading temperature or humidity takes about 250 milliseconds!
// Sensor readings may also be up to 2 seconds 'old' (its a very slow sensor)
float h = dht.readHumidity();
// Read temperature as Celsius (the default)
float t = dht.readTemperature();
// Read temperature as Fahrenheit (isFahrenheit = true)
float f = dht.readTemperature(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");
}
```

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