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?

Do what the meter supoorts?

[bugg]

Often the meter supports some sort of data export mechanism, and you just need to tie into it. Hacker extraordinaire Poul-Henning Kamp did this with his gas meter. [freebsd.dk]

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

[jkerman]

They changed all our electricity meters (madison, WI) to wireless now. they just drive the truck by and read them all instantly.

I assume it would be getting popular elsewhere too. it would be fun if you could tap into that.....

Re:Check for WiFi

[jkerman]

they are wireless, but not wifi

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

[rew]

FYI, here in holland you just pay a guesstimate every month, and they give you a final bill every year.

They try to get a meter reading every year. They trust you to do it yourself. They send a guy over every once in a while (i.e. every 5 years or so) to keep you honest. All you can do is postpone the stuff for a while. If you move you either have to arrange for an official meter-taking, or you have to sign a common "agreed meter-positions" note with the next inhabitant.

Apparently they HAVE to check the readings every three years. In practise they don't.

So, here in the Netherlands, most meters are on the insides of houses, and accessible for home owners to put a camera in front.

Re:what's your goal?

[LoRdTAW]

He should just buy a digital watt hour meter that uses 2 piece or clamp type current transducer coils. It might use rs-232 or usb and just read in the values from the device. There are plenty which are commercially available.

You can make your own using a micro controller with a few A-D channels to read the values of the current transducers and voltage using isolating transformers. Then just read in the two values, figure out the power factor and multiply the volt-amps by the power factor for watts. Then just tell the PMC to stream out the readings at intervals. Then use your PC to read the values from the PMC and your set.

Image processing is over complicating the entire system. Most of your time and code is going to be spent on "looking" at a meter.

ImageJ - open source image analysis tool

[dustingrzesik]

Lots of folks have suggested methods for developing an algorithm so I'll point you to some software that is free and very powerful. ImageJ is funded by the National Institutes of health, it is freely available and more than capable of the degree of image analysis you'll require. As others have mentioned image quality and consistency can be a huge hurdle so make life easier by setting everything up with care.