Idea for a new Show

I've been busy on this same problem for some time now, and I can't get it to finish.

My idea in short is; use a sensor from a optical mouse and a raspberry pi, to count the rotation frequency of your kwh meter to determine how much power you are using in your house.

I've been busy on idea like this for a while, and found out that a common mouse sensor (adns 2610) can be used as a 'tiny' scanner. (Sprites mods - Optical mouse-cam - Optical mouse cam)

So it should be possible to use the mouse sensor to find out if the little black dot of your Kwh meter is flying pass.

I'm stuck on two problems;

-I'm not very handy on programming in Linux

-because the wheel is behind glass, you need a different lens for a clear image. But maybe thats not so much of a problem because, you have to only detect the black spot.

I allready have a Pi near to my Kwh meter for my home automation.

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0 PaulMakesThings over 11 years ago

It might be easier to stick it on the digit read out. I see some little white tick lines on the 1/10 dial, they are distinct and evenly spaced. You might have better luck placing your sensor on that. But here's an alternative idea; I wouldn't be surprised if you can get a measurable variance if you stick a photo diode right up against the glass where the white tick lines are for the 1/10 dial and hit them with a cheap laser pointer.

Here's an example circuit for a photodiode from LetsMakeRobots:
http://letsmakerobots.com/files/userpics/u1533/Photodetector.jpg
if you search for photo detector circuit you will find many that either use op amps or transistors.

That would give you a signal that would go higher and lower as a line passed under it, but it likely wouldn't be logic level high and low, unless you're just lucky. It may be for example 3.1-3.7V in one state and 1.6-2.2V in the other. From there you could either use an analog input and logically separate out these states, or use a comparator IC against a voltage divider potentiometer to chop your analog singal into a digital readable high low.

Like this (copy pasted, not mine)
http://4.bp.blogspot.com/-cvKWtb9BmUc/Tvk2p1s813I/AAAAAAAAAXA/OSBWjQrjcc4/s1600/voltage+divider+with+comparator+circuit.…
but of course the two resistors are the pins of the potentiometer.

Hope this idea helps
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0 Former Member over 11 years ago in reply to PaulMakesThings

Thanks for thinking along, but for me, your solution sounds much more complex that it has to be. Given, I'm not that good in electronic as you probally are.

But still, I've taken the sensor from the mouse allready, and I allready hooked it up to my Pi. I do get readings. Al I used was and old mouse...

Thanks for thinking aloung thou!
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0 Former Member over 11 years ago in reply to PaulMakesThings

Thanks for thinking along, but for me, your solution sounds much more complex that it has to be. Given, I'm not that good in electronic as you probally are.

But still, I've taken the sensor from the mouse allready, and I allready hooked it up to my Pi. I do get readings. Al I used was and old mouse...

Thanks for thinking aloung thou!
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