import MypcDuinoIO
import time
from fractions import Fraction

class dht22:

	def read(self,pin,retries):
		mypin=pin
		mytries=retries
		if mytries==0:
			x=self.getdht22(mypin)
		elif mytries<0:
			x=1
			while x>0:
				x=self.getdht22(mypin)
		elif mytries>0:
			for i in range(0,mytries):
				x=self.getdht22(mypin)
				if x==0:
					break
				else:
					time.sleep(0.1)
		return x

	def getdht22(self,pin):
		myerror=0
		testpin=pin
		Mybits=''
		Mylist=[]
		count=1
		MyPin = MypcDuinoIO.pin(testpin,1)
		MyPin.low()
		time.sleep(0.0006)
		MyPin.setmode(0)
		for i in range(0,41):
			while MyPin.state()==0:
				pass
			while (MyPin.state()==1 and count<20):
				count += 1
			if count>=20:
					myerror=1
					break
			if count>2:
				Mylist.append('1')
			else:
				Mylist.append('0')
			count=1
		Mybits=''.join(Mylist)
		if len(Mybits)<41:
			self.tempc=0
			self.humid=0
			return 3
		temp=int(Mybits[1:17],2)+int(Mybits[18:33],2)
		if temp>255:
			temp=temp-256
		crc=int(Mybits[33:41],2)
		if temp==crc:
			myerror=0
		else:
			myerror=2
		MyTemp=int(Mybits[18:33],2)
		if MyTemp>32767:
			MyTemp=32768-MyTemp
		self.tempc=MyTemp/10.0
		self.humid=int(Mybits[1:17],2)/10.0
		return myerror

	def temperature(self):
		return self.tempc

	def humidity(self):
		return self.humid

	def dewpoint(self):
		expo=Fraction('1/8')
		temp=(self.humid/100)**expo
		temp2=temp*(112+(0.9*self.tempc))+(0.1*self.tempc)-112
		return "%.2f"%temp2
MypcDuinoIO.py
import os

class pin:
	GPIO_MODE_PATH= os.path.normpath('/sys/devices/virtual/misc/gpio/mode/')
	GPIO_PIN_PATH=os.path.normpath('/sys/devices/virtual/misc/gpio/pin/')
	GPIO_FILENAME="gpio"
	thepin=''

	def __init__(self,mypin,mode):
		self.gpio=mypin
		self.mode=mode
		self.pinMode=(os.path.join(self.GPIO_MODE_PATH, 'gpio'+str(self.gpio)))
		self.pinData=(os.path.join(self.GPIO_PIN_PATH, 'gpio'+str(self.gpio)))
		file=open(self.pinMode,'r+')
		file.write(str(self.mode))
		file.close
		self.file=open(self.pinData,'r+',0)

	def high(self):
		self.file.write("1")
		self.thepin=1

	def low(self):
		self.file.write("0")
		self.thepin=0

	def toggle(self):
		if self.thepin==0:
			self.high()
		else:
			self.low()

	def state(self):
		self.file.seek(0)
		return int(self.file.read(1))

	def setmode(self,x):
		self.mode=x
		file2=open(self.pinMode,'r+')
		file2.write(str(self.mode))
		file2.close

	def __del__(self):
		self.file.close

class adc:
	ADC_PATH=os.path.normpath('/proc/')
	raw=0

	def __init__(self,pin):
		self.adc=pin
		if self.adc==0 or self.adc==1:
			self.adcMult=2/62
		else:
			self.adcMult=3.3/4095
		self.adcData=(os.path.join(self.ADC_PATH, 'adc'+str(self.adc)))
		self.file=open(self.adcData,'r')

	def raw(self):
		self.file.seek(0)
		value=self.file.read(9)
		value=int(value[5:len(value)])
		return value

	def volts(self):
		self.file.seek(0)
		value=self.file.read(9)
		value=int(value[5:len(value)])
		if value==0:
			return 0
		else:
			return '%.4f'%(value*self.adcMult)

	def __del__(self):
		self.file.close
test22.py
import dht22

MyDHT22=dht22.dht22()

## read(pin number, retries)
## 0 retries means it tries only once
## greater than 0 and it will retry that number of times
## less than 0 ad it will retry forever until it gets a good CRC check
test=MyDHT22.read(2,0)
## The return = 0 if its good anything else is an error
print test
## Temperature in degress celcius
print MyDHT22.temperature()
## Humidity in %
print MyDHT22.humidity()
## Calculated dew point in degress celcius
print MyDHT22.dewpoint()