[john] sent in his version of a power meter monitor. It’s designed to monitor the blinking light on the meter to monitor the current power usage. The light flashes in proportion to the amount of power being used, so it was a matter of using a ldr/photoresistor to capture the output and feed it to the parallel port of his computer. To finish it up, he used a shell script to feed the data into MRTG.
pretty interesting. Now anybody who builds one, will be able to monitor energy usage without moving from the desktop. Another way of lazyness :P ..
Perhaps an interesting development could be a CCD or two (recycled from an old optical mouse) positioned so that they can read the numerical display on the meter, OCR it and present the info to the user over the LAN. (perhaps using an NSLU-2 or even a fonera…). This data could then be read by a Firefox (for example) plugin and could flash up a warning when the meter is about to run out of credit.
Just an idea…
I did consider pointing a webcam at the meter, but there wasn’t a convenient place to mount it. But there’s no need to do that — you can figure out how much electricity has been used by counting the flashes, and then it’s just a matter of calibrating that against the money-left display (and remembering to reset the counter when you add more credit, of course). Maybe for the next version…
Adam – apologies for inadvertently stealing your glory. I never claimed it to be my idea, but thought it was far too elegant not to share with Will and the Hackaday crowd.
Will – How about an [edit] to put Adam where he belongs?
:-)
I had a similar setup capturing the flashes on my meter a couple of years ago, eventually the electricity company forced me to take it off. ‘We’re too stupid to understand what you are doing, so either take it off or we will take it off and bill you for it’ etc etc. They were trying to claim it was some device for making the meter go backwards, even though I had set it up so that nothing was anywhere near the meter – even the phototransistor was a good few inches away.
Not that i’m bitter or anything… :)
Nice hack but you should attach the photoresistor differently. Right now it looks like some plastic explosive with a detonater attached.
this idea is very old. there are millions of projects like this. cheap and no leds
“sent in his version of a power meter monitor”
might have meant to be
“sent in this version of a power meter monitor”
you have to pay for you power before you use it? TVA Tennessee Valley Authority) and all their co-ops allow you to pay after using it, I like it better that way, as you never know when I may become unsatisfied with my power, and want a refund…
Apparently there is a DIN standard which governs the flash rate of the LED usage indicator on power meters. All DIN power meters have these indicators on them. They allow automated monitoring of power usage by a device which attaches directly to the meter and monitors the flash rate.
I used to do the same in the UK, until I moved house and now i’m stuck with the spinning disc form of meter, and its not got clear plastic casing so cannot use the other method of shining a light/laser through to count the spins :(
And yep, the electricity company really don’t know how to deal with people who want to check on their own usage. They throw a fit with hardware connected/watching/near the meter, then if you ring them for official howto do this, they fob you off.
I’m currently investigating how to use magnetic coil pickups on my power cables from my fuse box (separated leads from it, so should be easy to use a coil pickup on the live).
Anyone got any pointers??
Check out http://www.flukso.net/ for Wifi Household Power Logging.
http://www.jokamajo.org/ gives more detail appears to be openwrt/arduino based
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Hey, that’s not [john]‘s, that’s mine. :)
But thanks to him for sending it in…