arduino控制的DHT11温湿度传感器程序 -

#define DHT11_PIN 0
int Led = 8;
int Buzzer = 7;
byte read_dht11_dat()
{
byte i = 0;
byte result = 0;
for (i = 0; i<8; i++)
{
while (!(PINC&_BV(DHT11_PIN)));
delayMicroseconds(30);
if (PINC&_BV(DHT11_PIN))
result |= (1 << (7 - i));
while ((PINC&_BV(DHT11_PIN)));
}
return result;
}
void setup()
{
DDRC |= _BV(DHT11_PIN);
PORTC |= _BV(DHT11_PIN);
pinMode(Led, OUTPUT);
pinMode(Buzzer, OUTPUT);
Serial.begin(19200);
Serial.println("Ready");
}
void loop()
{
byte dht11_dat[5];
byte dht11_in;
byte i;
PORTC &= ~_BV(DHT11_PIN);
delay(18);
PORTC |= _BV(DHT11_PIN);
delayMicroseconds(40);
DDRC &= ~_BV(DHT11_PIN);
delayMicroseconds(40);
dht11_in = PINC & _BV(DHT11_PIN);
if (dht11_in)
{
Serial.println("dht11 start condition 1 not met");
return;
}
delayMicroseconds(80);
dht11_in = PINC & _BV(DHT11_PIN);
if (!dht11_in)
{
Serial.println("dht11 start condition 2 not met");
return;
}
delayMicroseconds(80);
for (i = 0; i<5; i++)
dht11_dat[i] = read_dht11_dat();
DDRC |= _BV(DHT11_PIN);
PORTC |= _BV(DHT11_PIN);
byte dht11_check_sum = dht11_dat[0] + dht11_dat[1] + dht11_dat[2] + dht11_dat[3];
if (dht11_dat[4] != dht11_check_sum)
{
Serial.println("DHT11 checksum error");
}
Serial.print("Current humdity= ");
Serial.print(dht11_dat[0], DEC);
Serial.print(".");
Serial.print(dht11_dat[1], DEC);
Serial.print("%");
Serial.print("temperature = ");
Serial.print(dht11_dat[2], DEC);
Serial.print(".");
Serial.print(dht11_dat[3], DEC);
Serial.println("C");
if (dht11_dat[0] == 25)
digitalWrite(Led, HIGH);
else
digitalWrite(Led, LOW);
if (dht11_dat[0] == 28)
digitalWrite(Buzzer, LOW);
else
digitalWrite(Buzzer, HIGH);
delay(2000);
}

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