Webcam energy meter monitoring!

[manuka]

I'm presently involved with a significant domestic energy meter monitoring project here in NZ,&amp; have run across a clever webcam based approach just released by the UK crowd Calc-Electric =&gt;<A href='http://www.calc-electric.com/cehome.htm ' Target=_Blank>External Web Link</a>. OK-it seems to be needing an always on PC + USB cable snake thru' the house, but the motion detecting abilities look both innovative &amp; safe compared with clamping the switchboard phase wire using a popular (Oz./NZ) &quot;Centameter&quot; <A href='http://www.centameter.com.au/products.htm ' Target=_Blank>External Web Link</a> or the likes of the &quot;ironmongery&quot; shown gathered <A href='http://www.bigdry.orcon.net.nz/7meters.jpg ' Target=_Blank>External Web Link</a>. Naturally a wireless webcam could reduce cable clutter, but then power supplies may be an issue.

Quite a few DIY optical sensing approaches have been found use already <A href='http://offog.org/code/electricity.html ' Target=_Blank>External Web Link</a> etc( Mmm-looks Picaxable &amp; even 433 MHz wireless?) but the appropriate tech. nature of cheapo webcams certainly appeals, especially given the program is presently just UK &#163;2.

Any opinions/experiences? Stan



Edited by - manuka on 08/08/2007 10:49:00

 

[steliosm]

The DIY optical based approaches look very interesting and they can be PicAxed and be wireless (434MHz).

The problem here is that in order to have the real energy consumption calculated you must also have an indication of the actual voltage. E.g. in Greece the voltage it is said to be 220V. The voltage measured is somewhere 208 - 218V depending on where you live. Also, to make things more interesting the voltage at random times goes up and down. So, any calculations based on the voltage been 220V are wrong.

Those meters though could be a simple DIY energy meters just for indication and not for calculating costs.

 

[moxhamj]

You can avoid the cables by using wireless cameras. Type wireless security camera into ebay - cost is about $40. I am using a number of these and they certainly go 100m or more outside and work fine inside a house as well. You need a video capture card but these are very cheap. I might have to stop at this point, because I am struggling to think where a picaxe fits into this...

 

[hax]

Hi steliosm, actually I think you are calculating the costs directly without any error. Remember you are reading the meter that your electricity company is reading. So if your meter is wrong, then you are charged an incorrect amount anyway. But either way it will tell you how much your energy is costing you.

 

[steliosm]

Well , it might not be that obvious but I don' trust the meter the electricity company installed about 20years ago

 

[manuka]

20 years is nothing- here in NZ some of these meters are ~70-80 years old &amp; were installed when the house was first built! But these ARE the points at which the energy company reads your consumption of course...

Why the Picaxe prospect? It relates more to the simpler LDR approaches mentioned above that I'd considered,but thought too &quot;Mickey Mouse&quot;. These seemed to me to be akin to traffic counting via telescope rather than being on the kerb side. But in fact they may have scope after all.

The webcam metering crowd &amp; I in email contact already, &amp; considering such &quot;whoops&quot; as <b>KWH </b> instead of the correct <b>kWh </b> . Stay tuned. Stan

 

[sedeap]

*****************
20 years?... more like as Stan says... 70~90YO here too
so the trick may be put another meter inside your house
to control to the company itself...
Here some people &quot;use to do&quot; put one BIG magnet in the
rear of the meter to &quot;slow it down&quot; the reads.
Obviously, when catched Pay with jail and money.
One time one neighbour come to my front door with one
damaged device to &quot;control &amp; sense&quot; the E-meter, this
device act as &quot;butler&quot; and deliver some power to ground
to jam the meter, but wrong connected, burn all out.
Here the almost all E-meters use the &quot;non live&quot; return
to metering the power, so if you not use this &quot;black
wire&quot; don't be billed for that.
So this man go back home with his burned device and one
strong recomendation &quot;don't came again, I see nothing of
this, or I MUST call police next time&quot; OR when catch him
I be punished like him.

So the interesting part of this thread walk around to build
some gizmo to &quot;cross check&quot; the E-meter to the real power
delivered at home.
Because to read the existent E-meter... simply take a look
write back the numbers and feed it into some &quot;excel&quot; like
spreadsheet calculating program.

)

 

[Rickharris]

Assuming you want to monitor the amount of electricity used(yes/no?) why not simply monitor the current through the incoming cable.

At the risk of being stupid - as the wheel is connected mechanically to the dials - assuming the meter is working i.e. the electrical sensing part, and the calculations are correct what can go wrong.
If you want to control power usage then I have often ponderedt he value of counting people into a room - people out of a room - when it's empty turn off electrical items and turn the heat down. reverse process when they return.

Edited by - rickharris on 08/08/2007 15:36:59

 

[sedeap]

*****************
New generation of meters coming in parade march
wifi feature onboard by now.
see it <External Web Link>

)

PDF URL fixed

Edited by - sedeap on 08/08/2007 16:06:46

 

[hippy]

Rickharris : <i>Assuming you want to monitor the amount of electricity used(yes/no?) why not simply monitor the current through the incoming cable. </i>

You need the voltage as well.

Also, isn't it quite complex to measure AC power, especially with voltage and current out of phase ? Achieving that out-of-phaseness is I believe a trick used to 'reduce' AC power consumption in some industrial motors.

 

[papaof2]

The power meter your electric company installs (even the ancient ones) is designed to handle the power factor of non-resistive loads and to compensate for the variations in supply voltage. The &quot;motor&quot; in the meter uses two coils; the potential (voltage) coil and the current (amperage) coil. More info here: <A href='http://themeterguy.com/Theory/watthour_meter.htm' Target=_Blank>External Web Link</a> http://themeterguy.com/Theory/watthour_meter.htm

John

 

[Rickharris]

Yes hippy it is more complicated to measure AC but not very much so - Your house will only be supplied with a single phase and neutral making calculations easier.

I rather took the voltage as a set figure because here in the UK we are used to a very stable supply.

I believe the electricity board have to guarantee the accuracy of their meters as well by law.

 

[BeanieBots]

&quot;I rather took the voltage as a set figure because here in the UK we are used to a very stable supply.&quot;

Oh Rick.. if only that were true<img src="sad.gif" width=15 height=15 align=middle>
It used to be, but a few years ago the UK standard was changed from +/-5% to +10%-20%.

My personnal supply is quite abysmal. In a 24hr period it will typically vary between 235v and 255v.
On tues 14-Jul-2005 it was recorded at 282v for a period of 23 seconds (some spike) and then dropped to 235v for the next three hours. Short brownouts are VERY common.
But then, none of this comes as a great shock considering the neglect of our (once very good) national grid. It's in nearly as bad shape as our water/drainage systems.

Anyway, winge out of the way, you MUST include voltage and phase to get anything remotely close to power consumption and that is what your domestic meter does and very accurately by law.

I have one of the very new digital meters that can be read remotely but the meter-man still knocks on the door. Does anyone know the frequency and protocol used. Should be possible to catch it with a suitable radio module and a PICAXE??

Short of that, LDR and datalogger on the blinking LED.

 

[Rickharris]

This web site (Ofcom) gives the standard for the UK <A href='http://www.ofcom.org.uk/radiocomms/ifi/tech/interface_req/ukinterface2017.pdf ' Target=_Blank>External Web Link</a>

It has been some time since I had any reason to monitor the voltage on a regular basis (you can tell)- interesting that standards have dropped. I visited a power station recently and they were very proud of the strict control they maintained over their supply. (obviously not proud enough)

Is the issue with the distribution or the generation I wonder - the technology to maintain a tight control over voltage &amp; phase hasn't changed any and I doubt cost can come into it at the generation level anyway.

 

[BeanieBots]

I'm quite sure the power-station control is very tight and it is the distribution that lets it down. I can actually see the local power-station from my house so it's not like it has far to come but I doubt it's that simple.
Maybe I'm on an end-of-line transformer outlet and suffer the maximum fluctuations caused by varying load but my personal experience is that voltage fluctuates outside 'legal' limits.
Unfortunatley, I moved at around the same time our standards dropped so I cannot say if my poor supply is due to location or a genuine drop in standard.
I'd be curious to know what others have experienced in the UK. A few work collegues have told tales of more severe brown-outs than I experience so my personal perception is that the UK grid is close to collapse. Studying data from the 'dynamic-demand' site also indicates that even the frequency is far less stable than it used to be.

 

[manuka]

&quot;Clamping&quot; the phase cable at the switch board is of course THE traditional way to monitor ones domestic usage. Quality digital clamp meters are available here in NZ for as little as US$10 as well,<A href='http://www.manuka.orcon.net.nz/dmmclamp.jpg' Target=_Blank>External Web Link</a> although trades grade are more like x10 that.

Although (observing a STRONG safety slant) regarded as an easy task, many countries view it as illegal. Us Kiwis have quite liberal electrical regs., but Oz. states (Victoria,Q'Land) will read the riot act if a householder even replaces a fuse or wires a mains plug. Tampering with a switchboard could see you deported - back to Blighty maybe?!

Aside from the regs. it's naturally highly hazardous to balance on a wobbly chair while trying to attach a clamp to a wiring rats nest inside ones dark,cobweb covered &amp; inconveniently placed pre WW2 switchboard. Rubber insulation on old wires additionally may crack &amp; fall away if the cables are moved too = YIKES !

In spite of supply voltage swings, these should still average around the nominal value (230V here in NZ/Oz),so just the passing AC current will do as a consumption guide. Most domestic usage is considered RESISTIVE as well, &amp; although REACTIVE devices (such as standby appliances) are increasing, these still are small beer beside the real energy hogs of water &amp; space heating.

Optical meter reading has appeal akin to acoustic coupling of phone modems. Those with long memories may recall it was once illegal to connect electrically to the phone system, so speaker/mike &quot;cups&quot; evolved to allow linking by sound. Reading the dials/LEDs optically is similarly non invasive,&amp; although it's more of a challenge,you can rest easy with electrical regulations! Stan

 

[manuka]

BeanieBots: (Cross posting) Smart metering is obviously the way of the future,with 2.4GHz ZigBee especially well suited to drive bay/stroll by readings. Some meters are GSM cellular capable now too. But meter readers may still pop in just to check that branches are not in wires,or that meter tampering hasn't occurred. And they like their cuppa too!

 

[Ralpht]

Manuka,
Here in Victoria it's OK to change fuses at your main fuse box. Doing your own wiring ie: adding a GPO etc is allowed as long as it's been &quot;supervised&quot;/signed off by a qualified electrician.

I do my own anyway and get an electrician mate to sign off on it. He knows I'm not likley to stuff up so is happy to put his &quot;reputation&quot; on the line for me - so to speak.
I have out-laws in Queensland and yes, they say if you even open the fusebox cover your arse is grass.
A clamp meter is probabaly the best way to go, but make sure it's calibrated. I'd suspect the accuracy of some of those 'el-cheapo' ones you can get from tricky dickie etc.

 

 

[LizzieB]

RickHarris: Your house will only be supplied with a single phase and neutral making calculations easier.

That maybe true where you live, but it's not true in other countries, e.g. the US.

 

[manuka]

For those confused, 2 phase was common in NZ rural areas anyway, ensuring enough energy still came thru' for the stove after the long supply line runs. Maybe with the lower line voltage in US this is still needed?

 

[inglewoodpete]

&quot;2 phase&quot; is not strictly 2 phase at all but 2 x 230/240v secondaries on a single-phase distribution transformer. The voltage supplied is actually a centre tapped 460/480 volts. The idea is to get more power without going over comfortable current limits.

 

[hippy]

<i>a few years ago the UK standard was changed from +/-5% to +10%-20% </i>

The primary reason for that wasn't to lower the standard, but to make EU harmonisation of voltage easier. The whole of Europe went to 230V without anyone having to actually alter their mains voltages !

The percentages chosen look odd / wrong for that inent; it matches with Vrms or Vpeak but not the other, I can't remember which.

It also meant that anyone designing equipment to EU spec could have it used anywhere in Europe and in many non-European countries.

 

[Michael 2727]

Here in OZ, Victoria when the State owned the Electricity utils (SEC) before it was chopped up and sold off to private companies they would sell you a reconditioned kWH Meter, they used to give them to the apprentices to reco, rather than have them standing around doing nothing all day.
I bought one for $18.00 AUD around 15 years ago.
You had to tell them what you wanted it for and agree not to sell power to anybody.
I don't nkow if they are still available, couldn't hurt to ask tho.

 

[sedeap]

*************
here 208~225v are common <img src="sad.gif" width=15 height=15 align=middle>
and domestic appliances from UK or Europe works fine.

)

 

[papaof2]

&quot;Optical meter reading has appeal akin to acoustic coupling of phone modems. Those with long memories may recall it was once illegal to connect electrically to the phone system, so speaker/mike &quot;cups&quot; evolved to allow linking by sound.&quot;

I saw the ultimate in a sound-activated modem made by NCR. The &quot;cup&quot; mechanism sat on the cradle of a standard Western Electric 300 series telephone set (curved front, back, &amp; sides with rotary dial - weighed about 10 pounds) and the handset was placed on top of the cups. When the phone rang (sound detected by a microphone in the unit), a solenoid lifted the handset to answer the phone without a connection. When used with the newer 500 series phones (long sloped front, flat back) the plastic handset would be tossed acroos the room unless it had been taped to the lifter mechanism.

Wonderful electro-mechanical action and 300 baud communications as well ;-)

John

 

[Mycroft2152]

Remember tht was state of the art technology for tthe time!

My favorite was one of the first &quot;letter quality printers that consisted of an IBM Selecric typewriter with a bank of 80+ solonoids sittig on top of the keys.

Inan earlier part of this thread, there was a discussion of travel/commute times. I live a metropolitan area in the northeast USA and was especilly happy with 10 minute amublance ride to the hospital last month when I had a heat attack and ended up with a triple bypass.

There are pro's and con's to any lifesyle.

Myc

OOPs, that was part of another lengthy thread. Sill recovering.

Edited by - Mycroft2152 on 09/08/2007 23:00:20

Edited by - Mycroft2152 on 09/08/2007 23:01:38

 

[premelec]

There was a company &quot;Turtle Tech&quot; that claims carrier current meter transmission over many miles - taking hours to read the meter at very low baud rate - more likely they were [are?] radiating VLF transmissions considering transformers &amp; such... anyhow low band width and excellent receiver sensitivity can do wonders! The market emphasis seems to be on short range high speed just now...

 

[LizzieB]

&quot;For those confused, 2 phase was common in NZ rural areas anyway, ensuring enough energy still came thru' for the stove after the long supply line runs. Maybe with the lower line voltage in US this is still needed?&quot;

The US has &quot;split-phase&quot;. Transformer on the pole with a 240 volt center tapped secondary feeds three wires to house, 120-neutral-120. Lights and normal outlets are run from one or other 120 and neutral, big appliances, stove, hot tubs, etc run from 240 volts.

 

[Rickharris]

<BLOCKQUOTE><font size=1 face=arial>quote:<hr height=1 noshade>...last month when I had a heart attack and ended up with a triple bypass. <hr height=1 noshade></BLOCKQUOTE></font><font face='Verdana, Arial, Helvetica' size=2>

I do hope your getting better MC and make a full and happy recovery.