Initial spike filter implemented

dht.py

@@ -27,6 +27,9 @@ class dht_22(background_task):
 
     def __init__(self, gpio, data_callback=None):
         self.__data_callback__ = data_callback
+
+        self.__temp_monitor__ = gradient_monitor(.5, 'DHT Temperature')
+        self.__hum_monitor__ = gradient_monitor(5, 'DHT Humidity')
         self.__monitor__ = dht_22_monitor(300)
         # Initial the dht device, with data pin connected to:
         if not DEBUG:
@@ -37,13 +40,19 @@ class dht_22(background_task):
     def __run__(self):
         data = self.__dht_data_transmission__()
         if data is not None:
-            logger.debug('DHT-Communication: Successfully: %s', repr(data))
-            self.__monitor__.process(data)
-            if self.__data_callback__ is not None:
-                self.__data_callback__(**data)
-            if self.__monitor__.status():
-                logger.warning("DHT measurement stopped caused by too many identical values!")
-                self.close()
+            # check data
+            if self.__temp_monitor__.process(data[self.KEY_TEMPERATURE], data[self.KEY_TIME]) and self.__hum_monitor__.process(data[self.KEY_HUMIDITY], data[self.KEY_TIME]):
+                #
+                logger.debug('DHT-Communication: Successfully: %s', repr(data))
+                self.__monitor__.process(data)
+                if self.__data_callback__ is not None:
+                    self.__data_callback__(**data)
+                if self.__monitor__.status():
+                    logger.warning("DHT measurement stopped caused by too many identical values!")
+                    self.close()
+            else:
+                logger.warning("DHT-Gradient to high: Ignoring data %s!", repr(data))
+                
 
 
     def __dht_data_transmission__(self):
@@ -60,7 +69,7 @@ class dht_22(background_task):
                     time.sleep(self.RUN_SLEEP_TIME)
                 except RuntimeError as error:
                     # Errors happen fairly often, DHT's are hard to read, just keep going
-                    logger.info('DHT-Communication: ' + error.args[0])
+                    logger.debug('DHT-Communication: ' + error.args[0])
                     time.sleep(2.0)
                 except Exception as error:
                     self.__dht_device__.exit()
@@ -73,6 +82,24 @@ class dht_22(background_task):
             }
 
 
+class gradient_monitor(object):
+    def __init__(self, max_gradient):
+        self.__max_gradient__ = max_gradient
+        #
+        self.__last_value__ = None
+        self.__last_time__ = None
+
+    def process(self, value, time):
+        rv = True
+        if self.__last_value__ is not None and self.__last_time__ is not None:
+            gradient = abs((value - self.__last_value__) / (time - self.__last_time__))
+            if gradient > self.__max_gradient__:
+                rv = False
+        self.__last_value__ = value
+        self.__last_time__ = time
+        return rv
+
+
 class dht_22_monitor(object):
     def __init__(self, max_const_treshold=250):
         self.__max_const_treshold__ = max_const_treshold
@@ -97,8 +124,6 @@ class dht_22_monitor(object):
                 if self.__current_const_measurements__ > self.__max_const_measurements__:
                     self.__max_const_measurements__ = self.__current_const_measurements__
             else:
-                if self.__current_const_measurements__ >= self.__max_const_measurements__:
-                    logger.warning('%d identical data measurements identified!', self.__max_const_measurements__)
                 self.__init_statevars__()
         if self.__max_const_measurements__ > self.__max_const_treshold__:
             if not self.__fail__: