#include <Wire.h>
#define I2CADDRESS 0x38
uint8_t buf[6];

void setup() {
  Wire.begin();
  Serial.begin(115200);
  Serial.println("DHT20:Tempratue  Humidy");
}

int dht20(){
  uint8_t chk=1;
  while(chk) {
    Wire.beginTransmission(I2CADDRESS);
    Wire.write(0xac);
    Wire.write(0x33);
    Wire.write(0x00);
    Wire.endTransmission();
    delay(80);/* 80mS遅延 */
    Wire.requestFrom(I2CADDRESS,6);
    for(uint8_t i=0;i<6;i++) buf[i]=Wire.read();
    chk=(buf[0]&0x80);
  }  
  return chk;
}

float getHumidy(){
  long t;
  t= ((buf[1]<<8) | (buf[2]))<<4 | (buf[3]>>4 &0x0f);
  return t/10485.76;
}

float getTemprature(){
  long t;
  t=(((buf[3]&0x0f)<<8) | buf[4])<<8 | buf[5];
  return t/5242.88-50;  
}

void loop() {
  delay(1000); /*1秒ごとに更新*/
  dht20();
  Serial.print(String(getTemprature()) + " deg ");
  Serial.print(String(getHumidy()) + " % ");
  Serial.println();
}