This app all started earlier today when I was thinking about how much electrical effect (kWh) the flashing light on my power meter indicated. It's situated outside, 30 or so meters away so I have no way of reading the digits, but I can see the light flashing just fine.
It flashes a 1000 times for every spent kWh. So, I figured, by feeling the rythm of the flashing led light, and clicking the same rythm on my phone I could calculate a (very) approximate load. For instance, at a rate of 1000 blinks an interval of 3.6 seconds would tell the effect spent is a kWh.
Said and done, here is the app. All free and easy to use. Just download it, start it, look at the blinking lights and click the button to see how much electricity you're currently wasting.