DHT22 Setup, with Simple Error Checking

1// Example testing sketch for various DHT humidity/temperature sensors
2//  Written by ladyada, public domain
3
4#include "DHT.h"
5
6#define DHTPIN  2     // what digital pin we're connected to
7
8#define DHTTYPE DHT22
9
10DHT  dht(DHTPIN, DHTTYPE);
11
12void setup() {
13	Serial.begin(9600);
14	Serial.println("Reading  DHT22 data!");
15	dht.begin();
16	pinMode(12, OUTPUT); // Green
17	pinMode(11,  OUTPUT); // Red
18}
19
20void loop() {
21	// Reading temperature or humidity  takes about 250 milliseconds!
22	// Sensor readings may also be up to 2 seconds  'old' (its a very slow sensor)
23	float hum1 = dht.readHumidity();
24	// Read  temperature as Celsius
25	float temp1 = dht.readTemperature();
26
27
28	//  Check if any reads failed and exit early (to try again).
29	if (isnan(hum1) ||  isnan(temp1)) {
30		digitalWrite(11, HIGH);
31		digitalWrite(12, LOW);
32		Serial.println("Error  in reading sensor data!");
33		while (isnan(hum1) || isnan(temp1)) {
34			hum1  = dht.readHumidity();
35			temp1 = dht.readTemperature();
36		}
37	}
38	else  {
39		digitalWrite(11, LOW);
40		digitalWrite(12, HIGH);
41	}
42
43	//  Wait a few seconds between measurements.
44	delay(3000);
45	float hum2 = dht.readHumidity();
46	float  temp2 = dht.readTemperature();
47
48	// Compute heat index in Celsius (isFahreheit  = false)
49	float hic = dht.computeHeatIndex(temp1, hum1, false);
50	Serial.print("Humidity:  ");
51	Serial.print(round)(hum1 + hum2) / 2));
52	Serial.print(" % ");
53	Serial.print("Temperature:  ");
54	Serial.print((temp1 + temp2) / 2);
55	Serial.print(" *C ");
56	Serial.print("Heat  index: ");
57	Serial.print(round(hic));
58	Serial.println(" *C ");
59}
60