RaspiWatt: discover power consumption using a Kill-A-Watt & Pi

Sorry for not responding, Drew. Things have been rather hectic over the last week and I haven't had time to tinker with this. I'll get into it again tomorrow and let you know how it goes. Thanks again for all the help.

Any luck so far?  Did my explanation make sense?  If you're interested, I could try to simulate another xbee transmitter and see if I can get the code to calculate the kWh & cost per sensor.

The dot operator accesses data or methods that are stored in a object.  Take a look at https://github.com/misterbonnie/Tweet-a-Watt/blob/master/sensorhistory.py.  This defines on line 15:

class SensorHistories:

    # array of sensor data

    sensorhistories = []

in https://github.com/misterbonnie/Tweet-a-Watt/blob/master/wattcher_cosm.py on line 6:

import sensorhistory

That is importing the SensorHistories module into our program, wattcher_cosm.py. On line 160:

sensorhistories = sensorhistory.SensorHistories(logfile)

This creates a SensorHistories object from the sensorhistory module and can be referenced as sensorhistories in our program now.  So this line 295:

        for history in sensorhistories.sensorhistories:

            wattsused += history.avgwattover5min()

            whused += history.dayswatthr

This will iterate through each itme in the array called sensorhistories inside the sensorhistories object.  Each iteration of the for loop will place the next item from the sensorhistories array into history.  Since history is a reference to a SensorHistory object, it has methods avgwattover5min which is on line 123 of sensorhistory.py:

  def avgwattover5min(self):

      return self.cumulative5mwatthr * (60.0*60.0 / (time.time() - self.fiveminutetimer))

So I think what is happening is that wattsused and whused is cumulative to all the sensors.  Thus the cost we calculate will also be cumulative for all the sensor.

It does, and I've been fiddling with that part of the file. I'm pretty new to python though, so tell me if I'm wrong, but is the dot syntax in python unlike that in other languages like C? When did history become a file or class that contains the methods avgwattover5min() and dayswatthr? I should also say I'm not the most experienced developer beyond python as well.

Hi - I'm looking at the original code https://github.com/adafruit/Tweet-a-Watt/blob/master/wattcher.py and also the design document http://www.ladyada.net/make/tweetawatt/database.html.  Unfortunately, I don't have the equipment right now to test it myself.

I think the trouble is that it is using the sensor histories for all sensors.  From your gist, line 269:

        # Taking avgwattover5min from ALL or only one sensor => erronious KWh

        for history in sensorhistories.sensorhistories:

            wattsused += history.avgwattover5min()

            whused += history.dayswatthr

I think this would need to be filtered based on the sensornum.  Does that make sense?  I should be able to get the equipment later this week to test it out myself.

Thanks,

Drew