Saving Energy Via Webcam-Based Meter Reading?

squoozer writes "Like many people, I am trying to cut down on the amount of energy my family and I use in order to save both the environment and my pay packet. Since I want to do this in as scientific a way as possible, I'm taking meter readings every day and recording them in a spreadsheet (OOo Calc naturally). Currently, in the UK at least, neither gas nor electricity meters can be hooked up to any sort of device that can query the meter for its current reading. Rather than climb down into the cellar every day to read the meters, it would be great if I could simply position a webcam in front of each meter and have the value logged automatically each day. The problem is that while I am a software developer (Java mostly) I have no experience in image processing (dials from the electricity meter) and don't really know where to start with this project." Does anyone have any advice for analyzing the visual data this reader would be gathering?

what's your goal?

[gEvil (beta)]

I'd say your approach completely depends on your goal. If your goal is as stated, then I'd use the webcams to get shots of the meters, then I'd take the 2-3 minutes or whatever it takes a week to pull up those images and transcribe their values into the spreadsheet. If the goal is a programming exercise, then go to town with figuring out some way to automate that few-minutes-a-week task. Of course, in order to do that, you'll expend a whole lot more energy than you'd take to read the meters (via the webcam shots) yourself.

Possible Implementation

[orclevegam]

Depending on the color of the faceplate and the hand, you might be able to mask off everything you don't care about (say everything but a small area around the center of the dial), run it through a hi/low filter to map the faceplate to white and the hand to black, and then just calculate the angle of the hand by searching the edge of the image for black pixels. So long as the cam is fixed and you know the coordinates of the pivot point it should be trivially easy to determine the angle of the hand based on the point at which it crosses the edge of the detection area. Once you've got the angle it should be trivially easy to map that back to a set of values.

Re:this is lame

[networkBoy]

Dear /.

Like so many others, I have a project I want to do. The project involves doing X, but alas I can not do X myself. Have any other /.ers done this and have some sample code I can look at and learn how to do this myself?

regards,

someGuyWhoWantsToBeABetterGeek

Re:I don't know if it's anything like in Canada

[the_other_one]

But you must not block the meter dials from view. Someone goes to check the values manually, every once in a while (monthly?).

If you have the same kind of "spinning wheel with a mark" under the small dials, it might be easier to check for the number of revolutions of that wheel.

Of course your biggest power drain will be from the computer that is always on reading the meter.

Re:this is lame

[joshuac]

How is it lame to ask other people questions when learning how to do something yourself?

Re:what's your goal?

[jibjibjib]

He probably has a computer running all the time anyway. And a webcam presumably doesn't consume much power, especially if it's turned off most of the time and just wakes up occasionally to grab a single frame.