From: Erik Andresen <erik@vontaene.de>
Date: Sun, 25 Dec 2016 10:23:11 +0000 (+0100)
Subject: added i2c/humidity
X-Git-Url: https://defiant.homedns.org/gitweb/?a=commitdiff_plain;ds=sidebyside;h=1e900f8150af092dd46c690a48b2541a36a6bca0;p=pyshared.git

added i2c/humidity
---

diff --git a/humidity.py b/humidity.py
new file mode 100755
index 0000000..9e4d439
--- /dev/null
+++ b/humidity.py
@@ -0,0 +1,65 @@
+#!/usr/bin/env python
+# -*- coding: iso-8859-15 -*-
+
+RS = 8314.3 # J/(kmol*K) universelle Gaskonstante
+MW = 18.016 # kg/kmol Molekulargewicht des Wasserdampfes
+
+# Openweathermap
+STATION=2911298
+API_ID="41ff32c10636d35b4c7a46000cb1a6a1"
+
+import urllib
+import json
+
+# Sättigungsdampfdruck in hPa
+def calc_saturation_vapor_pressure(temp_c):
+	if temp_c >= 0:
+		a = 7.5
+		b = 237.3
+	else:
+		a = 7.6
+		b = 240.7 
+	
+	return 6.1078 * 10**((a*temp_c)/(b+temp_c))
+
+
+# https://www.wetterochs.de/wetter/feuchte.html
+def calc_humidity_abs(temp_c, humdity_rel):
+	temp_k = temp_c + 273.15
+
+	# Dampfdruck in hPa
+	SDD = calc_saturation_vapor_pressure(temp_c)
+	DD = humdity_rel/100.0 * SDD
+	humidity_abs = 10**5 * MW/RS * DD/temp_k
+	return humidity_abs
+
+
+def calc_humidity_rel(temp_c, humidity_abs):
+	temp_k = temp_c + 273.15
+	SDD = calc_saturation_vapor_pressure(temp_c)
+	DD = humidity_abs*temp_k * RS / (10**5*MW)
+	
+	humdity_rel = DD/SDD*100
+	return humdity_rel
+
+def get_weather_current():
+	query = urllib.urlencode({'id': STATION, 'APPID': API_ID, 'lang': 'de'})
+	url = "http://api.openweathermap.org/data/2.5/weather?units=metric&%s" % query
+	response = urllib.urlopen(url)
+	results = response.read()
+	return json.loads(results)
+
+def check_ventilate(temp_indoor, humdity_rel_indoor):
+	dWeatherCurrent = get_weather_current()
+	temp_outdoor = dWeatherCurrent["main"]["temp"]
+	humdity_rel_outdoor = dWeatherCurrent["main"]["humidity"]
+
+	humdity_abs_indoor = calc_humidity_abs(temp_indoor, humdity_rel_indoor)
+	humdity_abs_outdoor = calc_humidity_abs(temp_outdoor, humdity_rel_outdoor)
+
+	print "Wassergehalt Innen: %.2f, Außen: %.2f" % (humdity_abs_indoor, humdity_abs_outdoor)
+	return humdity_abs_indoor - humdity_abs_outdoor
+
+
+if __name__ == "__main__":
+	check_ventilate(21, 50)	
diff --git a/i2c.py b/i2c.py
new file mode 100755
index 0000000..2e9a109
--- /dev/null
+++ b/i2c.py
@@ -0,0 +1,72 @@
+#!/usr/bin/env python
+# -*- coding: iso-8859-15 -*-
+
+import threading
+import inspect
+import os
+import logging
+from ctypes import *
+from time import sleep
+
+DEBUG=0
+logger = logging.getLogger(__name__)
+
+class i2c:
+	libc = CDLL("libc.so.6")
+	I2C_SLAVE = 0x0703  # Use this slave address
+	__single = None
+	__lock = threading.Lock()
+	__parent_owner = None
+
+	def __init__(self, addr):
+		with i2c.__lock:
+			count = 0
+			while(i2c.__single):
+				parent = inspect.stack()[1][3]
+				count += 1
+				sleep(0.001)
+			if DEBUG:
+				if count > 10:
+					parent_owner = "%s (%d), %s()" % (self.__parent_owner[1], self.__parent_owner[2], self.__parent_owner[3])
+					logger.warning("Error: (%s) I2C blocked %fs by %s!", parent, count*0.001, parent_owner)
+				i2c.__parent_owner = inspect.stack()[1]
+			i2c.__single = True
+		self.dev = i2c.libc.open("/dev/i2c-2", os.O_RDWR)
+		if self.dev < 0:
+			raise IOError("open")
+		err = i2c.libc.ioctl(self.dev, i2c.I2C_SLAVE, addr>>1)
+		if err < 0:
+			raise IOError("ioctl")
+
+	def write(self, s):
+		num_write = i2c.libc.write(self.dev, s, len(s))
+		if num_write != len(s):
+			self.close()
+			raise IOError("write: %d" % (num_write))
+	
+	def read(self, num):
+		buf = create_string_buffer(num)
+		num_read = i2c.libc.read(self.dev, buf, num)
+		if num_read != num:
+			self.close()
+			raise IOError("read: %d" % (num_read))
+		return buf.raw
+
+	def close(self):
+		if self.dev:
+			i2c.libc.close(self.dev)
+			self.dev = None
+			#i2c.__parent_owner = None
+			i2c.__single = None
+
+	def __del__(self):
+		self.close()
+
+if __name__ == "__main__":
+	import struct
+	import sys
+
+	dev = i2c(0x50)
+	s = struct.pack(">Bh", int(sys.argv[1]), int(sys.argv[2]))
+	dev.write(s)
+	dev.close()