#Lab4

[suchanoot11]

#Lab4.txt

[suchanoot11]

อธิบายหลักการทำงาน วัดอุณหภูมิและความชื้นสัมพัทธ์แบบดิจิทัล หากอุณหภูมิมากกว่า 30 องศา ไฟ LED จะติด

Source code

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); const int led = 13; 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"); if (t > 30) { digitalWrite(led, HIGH); } else { digitalWrite(led, LOW); }

}