Grove - Temperature and Humidity Sensor

// Example testing sketch for various DHT humidity/temperature sensors
// Written by ladyada, public domain
 
#include "DHT.h"
 
#define DHTPIN A0 // what pin we're connected to
 
// Uncomment whatever type you're using!
#define DHTTYPE DHT11 // DHT 11
//#define DHTTYPE DHT22 // DHT 22 (AM2302)
//#define DHTTYPE DHT21 // DHT 21 (AM2301)
 
// Connect pin 1 (on the left) of the sensor to +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
 
DHT dht(DHTPIN, DHTTYPE);
 
void setup()
{
    Serial.begin(9600);
    Serial.println("DHTxx test!");
 
    dht.begin();
}
 
void loop()
{
    // Reading temperature or humidity takes about 250 milliseconds!
    // Sensor readings may also be up to A0 seconds 'old' (its a very slow sensor)
    float h = dht.readHumidity();
    float t = dht.readTemperature();
 
    // check if returns are valid, if they are NaN (not a number) then something went wrong!
    if (isnan(t) || isnan(h))
    {
        Serial.println("Failed to read from DHT");
    }
    else
    {
        Serial.print("Humidity: ");
        Serial.print(h);
        Serial.print(" %\t");
        Serial.print("Temperature: ");
        Serial.print(t);
        Serial.println(" *C");
    }
}

#define DHTTYPE DHT11   // DHT 11 
//#define DHTTYPE DHT22   // DHT 22  (AM2302)
//#define DHTTYPE DHT21   // DHT 21 (AM2301)

/*
  Grove-Temperature-Humidity Sensor
 Read value from grove-temperature-humidity sensor then display on grove-4-digital-display
 
 The circuit:
 * 4-digital-display attached to pin38 & pin39 (J14 plug on Grove Base BoosterPack)
 * sig pin of the Grove-Temperature-Humidity Sensor to the analog pin 24 (Grove connector J6)
 * one side pin (either one) to ground
 * the other side pin to +VCC
 * LED anode (long leg) attached to RED_LED
 * LED cathode (short leg) attached to ground
 
 * Note: Put your hands on Grove-Temperature-Humidity Sensor, both of the value 
         will rise. 
 
         4-digital-display:
         |--------------------------|
         | temperature :  humidity  |    
         |--------------------------| 
 
 This example code is in the public domain.
 
 http://www.seeedstudio.com/wiki/Grove_-_Temperature_and_Humidity_Sensor_Pro 
 
 */
 
#include "TM1637.h" 
#include "DHT.h"
 
/* Macro Define */
#define CLK               39                  /* 4-digital display clock pin */
#define DIO               38                 /* 4-digital display data pin */
#define BLINK_LED         RED_LED            /* blink led */
#define TEMP_HUMI_PIN     24                 /* pin of temperature&humidity sensor */
 
/* Global Varibles */
TM1637 tm1637(CLK, DIO);                  /* 4-digital display object */
DHT dht(TEMP_HUMI_PIN, DHT22);            /* temperature&humidity sensor object */
 
int8_t t_bits[2] = {0};                   /* array to store the single bits of the temperature */
int8_t h_bits[2] = {0};                   /* array to store the single bits of the humidity */  
 
/* the setup() method runs once, when the sketch starts */
void setup() {
 
    tm1637.init();                       /* initialize 4-digital display */
    tm1637.set(BRIGHT_TYPICAL);          /* set the brightness */    
    tm1637.point(POINT_ON);              /* light the clock point ":" */
 
    dht.begin();                         /* initialize temperature humidity sensor */
 
    pinMode(RED_LED, OUTPUT);            /* declare the red_led pin as an OUTPUT */
 
}
 
/* the loop() method runs over and over again */
void loop() {   
 
    int _temperature = dht.readTemperature();             /* read the temperature value from the sensor */
    int _humidity = dht.readHumidity();                   /* read the humidity value from the sensor */    
 
    memset(t_bits, 0, 2);                                 /* reset array when we use it */
    memset(h_bits, 0, 2);
 
    /* 4-digital-display [0,1] is used to display temperature */
    t_bits[0] = _temperature % 10;
    _temperature /= 10;
    t_bits[1] = _temperature % 10;
 
    /* 4-digital-display [2,3] is used to display humidity */ 
    h_bits[0] = _humidity % 10;
    _humidity /= 10;
    h_bits[1] = _humidity % 10;
 
    /* show it */
    tm1637.display(1, t_bits[0]);
    tm1637.display(0, t_bits[1]);
 
    tm1637.display(3, h_bits[0]);
    tm1637.display(2, h_bits[1]);
 
}