Current Sensing?
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Yes, I imagine a requirement to monitor 9 or 10 separate meters at a single location is a bit of a one off, but I'll be definitely interested in what you come up with to see if I can utilise it. I expect I will be using an ESP8266 based board for the micro controller part as power supply is not an issue, and I have wifi available.
While researching bits and pieces across the internet I came across:
https://openenergymonitor.org/forum-archive/node/10707.html
which I thought may be of interest. It seems they are flashing the LED from a microcontroller output, which is an interesting way of proving that the overall system is working.
@mwalker - Okay, well at that quantity you may find it useful to get some PCBs ordered that i design and then put it in a enclosure that you can come up with (saving shipping costs from me to you). Unless you just directly copy my circuitry to your own solution, up to you! So yeah, if you wanted to use my circuitry you would just wire the three wires into the arduino rather than using a RJ11 connector, would be easier than making a enclosure with panel mounted jacks and stuff. Its much easier for me to use RJ11 connectors as i'm making the arduino side as a custom board too.
That is what i would call a backward solution. I do agree that it would allow you to see that the arduino is running, but its just not really the way i'm doing this. The LED that i will be blinking on the front of the module is being triggered by the Photodiode and comparator itself, nothing to do with the arduino (this way if someone needed to come to your meter, they can see the LED even if the arduino has failed, as long as its still getting its power. This is not really a design feature though, just a bi-product of how i've made it).
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@Samuel235 sounds good.
More digging identified the openenergymonitor sensor is a rebadged unit manufactured in China:
The link doesn't work but it is in the Internet archive, they have a (fuzzy) photo of the internals at right at the bottom:
http://web.archive.org/web/20160819224835/https://openenergymonitor.org/emon/opticalpulsesensor
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@Samuel235 sounds good.
More digging identified the openenergymonitor sensor is a rebadged unit manufactured in China:
The link doesn't work but it is in the Internet archive, they have a (fuzzy) photo of the internals at right at the bottom:
http://web.archive.org/web/20160819224835/https://openenergymonitor.org/emon/opticalpulsesensor
@mwalker - Same image as i found on one of the links above. They are not choosing to go the comparator method either. I will be interested to see how fast mine could detect pulses. I might take one into University/school and get the pulse/wave generator on it.
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@Samuel235
i don't think you need to go very high freq though, even with 50hz i think you can cover almost all meters you would need.Because 50hz would allow 50*3600= 180000 pulses/hour so if you say you go up to 20kw/h which is a lot! that would be 9000pulses/kw/h. So 100hz with a photores is a lot..
but sure photodiode could be useful maybe for some other usecase, i don't know..or for some data transmission lol but here it's more something like "dark or light" at "slow rate".
in case you have parts in stock and want to play, you still can use 3,4 resistors, cheap bs250 mosfet and photoresistor, very easy to use. My files are now uploaded at openhardware if you need https://forum.mysensors.org/topic/6430/mypulse-sensor
Another nice article about photoresistor and blinking led detection i've just discovered. Looks like i've decided to use a mosfet for switching and perhaps a better digital level.., thus saving the footprint size + cost of the potentiometer.
http://jeelabs.org/2012/03/18/detecting-a-blinking-led/ -
@Samuel235
i don't think you need to go very high freq though, even with 50hz i think you can cover almost all meters you would need.Because 50hz would allow 50*3600= 180000 pulses/hour so if you say you go up to 20kw/h which is a lot! that would be 9000pulses/kw/h. So 100hz with a photores is a lot..
but sure photodiode could be useful maybe for some other usecase, i don't know..or for some data transmission lol but here it's more something like "dark or light" at "slow rate".
in case you have parts in stock and want to play, you still can use 3,4 resistors, cheap bs250 mosfet and photoresistor, very easy to use. My files are now uploaded at openhardware if you need https://forum.mysensors.org/topic/6430/mypulse-sensor
Another nice article about photoresistor and blinking led detection i've just discovered. Looks like i've decided to use a mosfet for switching and perhaps a better digital level.., thus saving the footprint size + cost of the potentiometer.
http://jeelabs.org/2012/03/18/detecting-a-blinking-led/@scalz - I made it with a comparator for two main reasons:
- I wasn't sure how much the frequency fluctuated from country to country and instead of spending days on end doing research for that, I just chose to go safe rather than sorry.
- If there is another application that we're not thinking of that would take advantage of a fast/high frequency light detector, this would fit perfectly.
Thanks for uploading the files, will check them out today, although i pretty much have mine done now, just not got the design penalised onto the PCB to get 4 out of the 50x50 prototype order.
I will get it made at University to test the board too.
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@scalz the jeelabs post is interesting. When I was using an LM393 module with a LDR I was unable to detect the pulses coming from my meter (later established as 15ms). Reading that article it seems that was because of inadequate light proofing (the meter is shaded, but outdoors), but lacking any sort of test equipment, it's interesting to see his oscilloscope tracings of the response of the LDR to a pulse. Thanks for linking it.
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I have a Smappee energy monitor, it's connected to the main input and "detect" the different equipments. It's good to monitor the overall energy consumption and production if you have solar pannels but it's not able to detect everything.
In summary, it can tell you the consumption of anything with a resistor (electric oven, motor, cofee machine) or a motor (roller shutter, pump,...) but for electronic, PC and other things for which the power consumption is not regular it won't help you much. For this, I think monitoring individual component will be the best.But as you probably plus a pwoer meter on each plug, maybe a combintation of both will be a good choice.
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I use main line snap on current sensors for whole house monitoring, and snap on or hall effect sensors for specific device monitoring when necessary. I use current shunts for high current, low voltage dc monitoring like battery backup or off grid solar power systems.
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I use main line snap on current sensors for whole house monitoring, and snap on or hall effect sensors for specific device monitoring when necessary. I use current shunts for high current, low voltage dc monitoring like battery backup or off grid solar power systems.
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I also monitor the voltage (9v transformer and voltage divider) so I am getting current & voltage, and also time, so I can monitor KWh not just KW.
@sspence65
I think too that your method for power metering is better then calculating it from "blinks" of LED of power meter.
That is good for energy consumption only by counting pulses.
You can send correct power consumption in each time, which is not possible from blinks.
And I think in most cases we can assume stable voltage in the power net, so we do not need measure voltage. -
I have just posted my solution so far:
Forum thread: https://forum.mysensors.org/topic/6460/homini-pulse-meter-monitor
Openhardware.io: https://www.openhardware.io/view/356/Homini-Pulse-Meter-Monitor#tabs-commentsThe sensor part is designed, currently working on the custom microcontroller board - You're more than welcome to use an arduino or any other solution for a microcontroller module.
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@sspence65
I think too that your method for power metering is better then calculating it from "blinks" of LED of power meter.
That is good for energy consumption only by counting pulses.
You can send correct power consumption in each time, which is not possible from blinks.
And I think in most cases we can assume stable voltage in the power net, so we do not need measure voltage.@kimot
Actually counting pulses takes advantage of the supposedly accurate measurements of the main power meter instead of making your own. In addition from a safety perspective the less people work directly with 220v, the better.
IMHO assuming stable voltage it's not correct as it actually fluctuates even over 20V -
@kimot
Actually counting pulses takes advantage of the supposedly accurate measurements of the main power meter instead of making your own. In addition from a safety perspective the less people work directly with 220v, the better.
IMHO assuming stable voltage it's not correct as it actually fluctuates even over 20V -
@gohan
Yes, pulse counting is best for energy consumption ( kWh ), but is inapplicable for actual power
( W ) consumption measuring.
