Hello,
I'm a C++ newbie, I've done some small guided Arduino projects in the past and I decided to step up my game a bit, I'm working on a temperature controlled box. The set up is simple, two 5v relays and a RHT03 temperature and humidity sensor. Problem is the data sheet is pretty much useless and the example is leaving me a bit stumped.
Here's the example:
{
byte i = 0;
byte result=0;
for(i=0; i< 8; i++){
//We enter this during the first start bit (low for 50uS) of the byte
while(!(PINC & _BV(DHT11_PIN))); // wait until pin goes high
//signalling end of start of bit's transmission.
//Dataline will stay high for 27 or 70 uS, depending on if
// a 0 or a 1 is being sent, respectively
delayMicroseconds(30);//AFTER pin is high, wait further period, to be
//into the part of the timing diagram where a 0 or a 1 denotes
//the datum being send. The "further period" was 30uS in the software
//that this has been created from. I believe that a higher number
//(45?) would be more appropriate.
if(PINC & _BV(DHT11_PIN))//If pin still high
result |=(1<<(7-i));// "add" (not just addition) the 1 to the
//growing byte
while((PINC & _BV(DHT11_PIN))); // wait for pin to go low again, which
//signals he START of the NEXT bit's transmission.
}//end of "for.."
return result;
}//end of "read_dht11_dat()"
void setup()
{
DDRC |= _BV(DHT11_PIN);//set data pin... for now... as out(?)put
//DDRC is data direction register for pins A0-5 are on
PORTC |= _BV(DHT11_PIN);//(dis?)-connect internal pull up on line
//PORTC relates to the pins A0-5 are on.
Serial.begin(9600);
delay(300);//Let system settle
Serial.println("Humidity and temperature\n\n");
delay(700);//Wait rest of 1000ms recommended delay before
//accessing sensor.
}
void loop()
{
byte dht11_dat[5];//Array to hold the bytes sent from sensor. 0-4 should be enough
//don't belive dht11_dat[5] is used.
byte dht11_in;
byte i;
// Send "start read and report" command to sensor....
// 1. pull-down i/o pin for 18ms
PORTC &= ~_BV(DHT11_PIN);
}
Can someone please break this down in dummy friendly therms?
