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Здравствуйте! У меня есть такая проблема: DHT 22 не показывает минусовую температуру. Решение, взятое отсюда http://forum.amperka.ru/threads/dht-22-%D0%BD%D0%B5-%D0%BF%D0%BE%D0%BA%D0%B0%D0%B7%D1%8B%D0%B2%D0%B0%D0%B5%D1%82-%D0%BC%D0%B8%D0%BD%D1%83%D1%81%D0%BE%D0%B2%D1%83%D1%8E-%D1%82%D0%B5%D0%BC%D0%BF%D0%B5%D1%80%D0%B0%D1%82%D1%83%D1%80%D1%83.921/  не помогло((( 

файл .cpp библиотеки тут:

#ifndef DHT11_H
#include "dht22.h"



//######### Initialization and Pin Structures ###################
	dht22::dht22()
    {
		attach(2);//this is the default pin
    }

	dht22::dht22(int pin)
    {
		attach(pin);
    }

	//this will allow the bus of an instance of this library to be changed
	dht22::dht22(int pin, VersalinoBUS myBUS)
	{
		attach(pin, myBUS);
	}



void dht22::attach(int pin, VersalinoBUS myBUS)
{
	_sensorPin = pin;
	_myBUS = myBUS;
	_BUSenabled = true;

}

void dht22::attach(int pin)
{
	_sensorPin = pin;
	_BUSenabled = false;
}

	//This will return the VersalinoBUS currently assigned to the instance of this library
	VersalinoBUS dht22::getBUS()
	{
		return _myBUS;
	}

	void dht22::removeBUS()
	{
		_BUSenabled=false;
	}

	void dht22::setBUS(VersalinoBUS myBUS)
	{
		_myBUS = myBUS;
		_BUSenabled=true;
	}


//##################################################################

//##########################read DHT11##############################
// returnvalues:
//  0 : OK
// -1 : checksum error
// -2 : timeout


int dht22::read()
{
	if(_BUSenabled)
	return read(_myBUS.PINS[_sensorPin]);//if a BUS is attached then read using the Versalino Library
	else
	return read(_sensorPin);//reads from attached sensorPin (attach command must be run first or this will use the default pin 2)
}

int dht22::read(int pin, VersalinoBUS myBUS)
{
	return read(myBUS.PINS[pin]);//read from a pin on a VersalinoBUS using the Versalino Library
}


int dht22::read(int pin)
{
	// BUFFER TO RECEIVE
	uint8_t bits[5];
	uint8_t cnt = 7;
	uint8_t idx = 0;

	// EMPTY BUFFER
	for (int i=0; i< 5; i++) bits[i] = 0;

	// REQUEST SAMPLE
	pinMode(pin, OUTPUT);
	digitalWrite(pin, LOW);
	delay(18);
	digitalWrite(pin, HIGH);
	delayMicroseconds(40);
	pinMode(pin, INPUT);

	// ACKNOWLEDGE or TIMEOUT
	unsigned int loopCnt = 10000;
	while(digitalRead(pin) == LOW)
		if (loopCnt-- == 0) return -2;

	loopCnt = 10000;
	while(digitalRead(pin) == HIGH)
		if (loopCnt-- == 0) return -2;

	// READ OUTPUT - 40 BITS => 5 BYTES or TIMEOUT
	for (int i=0; i<40; i++)
	{
		loopCnt = 10000;
		while(digitalRead(pin) == LOW)
			if (loopCnt-- == 0) return -2;

		unsigned long t = micros();

		loopCnt = 10000;
		while(digitalRead(pin) == HIGH)
			if (loopCnt-- == 0) return -2;

		if ((micros() - t) > 40) bits[idx] |= (1 << cnt);
		if (cnt == 0)   // next byte?
		{
			cnt = 7;    // restart at MSB
			idx++;      // next byte!
		}
		else cnt--;
	}

	// WRITE TO RIGHT VARS
	humidity    = word(bits[0], bits[1]) * 0.1;//calculates and stores the humidity

	 uint8_t sign = 1;
	        if (bits[2] & 0x80) // negative temperature
	        {
	                bits[2] = bits[2] & 0x7F;//negative temp adjustments
	                sign = -1;
	        }
        temperature = sign * word(bits[2], bits[3]) * 0.1;//temp calculation and storage, change na -0.1


	uint8_t sum = bits[0] + bits[1] + bits[2] + bits[3];//sum values

	if (bits[4] != sum) return -1;//failed checksum
	return 0;//great success!
}

//##################################################################

//###############UNIT CONVERSIONS & CALCULATIONS####################
double dht22::celcius()
{
	read();//make sure the temp has been read

	return temperature;
}


//Celsius to Fahrenheit conversion
double dht22::fahrenheit(double dCelsius)
{
	return 1.8 * dCelsius + 32;
}

double dht22::fahrenheit()
{
	read();//make sure the temp has been read

	return fahrenheit(temperature);
}

//Celsius to Kelvin conversion
double dht22::kelvin(double dCelsius)
{
	return dCelsius + 273.15;
}

double dht22::kelvin()
{
	read();
	return kelvin(temperature);
}


// dewPoint function NOAA
// reference: http://wahiduddin.net/calc/density_algorithms.htm
double dht22::dewPoint()
{
	read();//make sure the temp has been read

	double A0= 373.15/(273.15 + temperature);
	double SUM = -7.90298 * (A0-1);
	SUM += 5.02808 * log10(A0);
	SUM += -1.3816e-7 * (pow(10, (11.344*(1-1/A0)))-1) ;
	SUM += 8.1328e-3 * (pow(10,(-3.49149*(A0-1)))-1) ;
	SUM += log10(1013.246);
	double VP = pow(10, SUM-3) * humidity;
	double T = log(VP/0.61078);   // temp var
	return (241.88 * T) / (17.558-T);
}

// delta max = 0.6544 wrt dewPoint()
// 5x faster than dewPoint()
// reference: http://en.wikipedia.org/wiki/Dew_point
double dht22::dewPointFast()
{
	read();//make sure the temp has been read

	double a = 17.271;
	double b = 237.7;
	double temp = (a * temperature) / (b + temperature) + log((double) humidity/100);
	double Td = (b * temp) / (a - temp);
	return Td;
}
//###############################################################



#endif // DHT22_H

собственно сам скретч

#include <dht22.h>

dht22 DHT22;

void setup()
{
  DHT22.attach(7);
  Serial.begin(9600);
  Serial.println("DHT22 TEST PROGRAM ");
  Serial.print("LIBRARY VERSION: ");
  Serial.println(DHT22LIB_VERSION);
}

void loop()
{
  Serial.println("\n");

  int chk = DHT22.read();

 // Serial.print("Read sensor: ");
  switch (chk)
  {
    case 0: Serial.println("OK"); break;
    case -1: Serial.println("Checksum error"); break;
    case -2: Serial.println("Time out error"); break;
    default: Serial.println("Unknown error"); break;
  }

  Serial.print("Humidity (%): ");
  Serial.println((float)DHT22.humidity, 2);

  Serial.print("Temperature (°C): ");
  Serial.println((float)DHT22.temperature, 2);


  delay(2000);
}

Вопрос, что здесь не так???