Anyone got one?

I just dumped EDF and switched to SE. Nice little surprise waiting for me
when I got down to the bungalow:

http://mungbean.org/blog/?p=477

A little clamp meter to whack on the meter tail, and a batter powered RF
transmitter (433MHz). Base unit sits in the house and tells you wn=hat
you're using.

I know it's hardly a unique concept, but it was free Brought it back and
hooked it up in Pembury.

There's a little RJ45 underneath, which upon some searching turned up the
above web site which suggests it's a TTL level serial link that spits out
readings in XML every 6 seconds at 2400 baud.

Need to go and see if I have a MAX232 somewhere and hook it up to the PC

Only deficiency is the base unit doesn't have a Rugby Clock receiver for
time, otherwise it would be nearly perfect...

Cheers

Tim

Tim S wrote:

Anyone got one?

Yep - I'm one of those "folk at Hursley Park" mentioned in the link.
Must admit I was never one of the more active ones though.

Need to go and see if I have a MAX232 somewhere and hook it up to the PC

I did that with mine, but by now they have actually produced the
promised cable and are selling them (including USB versions) via an eBay
shop. Might save you a bit of faffing putting one together.

Pete

"Tim S" wrote in message
...
Anyone got one?

I just dumped EDF and switched to SE. Nice little surprise waiting for me
when I got down to the bungalow:

http://mungbean.org/blog/?p=477

that is a re-branded current cost meter,

current cost sell the usb lead and have some software on their site to
download, so you can get the data from it,

depending which model of the meter you have, it may store the data for 45
days or more... i bought a current cost one and it stores 90 days of data i
believe... whcih is going to be very handy when i the managment company
finaly replace our boiler, as they are going to be getting a bill for the
extra electric from having to heat the house with lecky heaters.... they
think i can't prove it's costing almost 100 quid a month extra, but i have
the graphs in both monetry units and killowatt hours... up from an average
of 3kw a day before the boiler died, to over 14 kw a day after.

"Tim S" wrote in message
...
Anyone got one?

I just dumped EDF and switched to SE. Nice little surprise waiting for me
when I got down to the bungalow:

http://mungbean.org/blog/?p=477

A little clamp meter to whack on the meter tail, and a batter powered RF
transmitter (433MHz). Base unit sits in the house and tells you wn=hat
you're using.

I know it's hardly a unique concept, but it was free Brought it back
and
hooked it up in Pembury.

There's a little RJ45 underneath, which upon some searching turned up the
above web site which suggests it's a TTL level serial link that spits out
readings in XML every 6 seconds at 2400 baud.

Need to go and see if I have a MAX232 somewhere and hook it up to the PC


Only deficiency is the base unit doesn't have a Rugby Clock receiver for
time, otherwise it would be nearly perfect...

Cheers

Tim

The time signal is now transmitted from Cumbria

http://en.wikipedia.org/wiki/Time_from_NPL

Adam

Tim S wrote:
Anyone got one?

I just dumped EDF and switched to SE. Nice little surprise waiting for me
when I got down to the bungalow:

http://mungbean.org/blog/?p=477

A little clamp meter to whack on the meter tail, and a batter powered RF
transmitter (433MHz). Base unit sits in the house and tells you wn=hat
you're using.

I know it's hardly a unique concept, but it was free Brought it back and
hooked it up in Pembury.

There's a little RJ45 underneath, which upon some searching turned up the
above web site which suggests it's a TTL level serial link that spits out
readings in XML every 6 seconds at 2400 baud.

Need to go and see if I have a MAX232 somewhere and hook it up to the PC

Only deficiency is the base unit doesn't have a Rugby Clock receiver for
time, otherwise it would be nearly perfect...

Cheers

Tim

I can't see the value for logging the data from Current Cost units apart
from the initial technical challenge. With so many domestic loads being
non resistive, and these units not taking a phase reference, they are
bound to be inaccurate. Yes they will give a relative indication to help
track down wasted power but that is about all they are good for. It
would be so easy to have a smarter clamp head that also plugged in to a
mains socket and have the pic calculate true RMS power.
Does anyone know of a unit that does this properly?

Bob

On Sun, 31 May 2009 00:40:19 +0100, Pete Verdon wrote:

I did that with mine, but by now they have actually produced the
promised cable and are selling them (including USB versions) via an eBay
shop. Might save you a bit of faffing putting one together.

USB only available now, I asked about RS232 a while back and they said
"until stocks exhausted".

http://stores.shop.ebay.co.uk/Current-Cost-Ltd

--
Cheers
Dave.

ARWadsworth coughed up some electrons that declared:


The time signal is now transmitted from Cumbria

http://en.wikipedia.org/wiki/Time_from_NPL

Adam

Yep - I know

I still call it "rugby" though - bit like buying a "biro", everyone knows
what you mean :-

Now, a real man would throw the base unit away and hack the RF...

Cheers

Tim

PS

Have a couple of MAX232 RS232 converters, so I'll see what it does later.
The real fun will be to see if it accepts commands...

Bob Minchin coughed up some electrons that declared:

I can't see the value for logging the data from Current Cost units apart
from the initial technical challenge. With so many domestic loads being
non resistive, and these units not taking a phase reference, they are
bound to be inaccurate. Yes they will give a relative indication to help
track down wasted power but that is about all they are good for. It
would be so easy to have a smarter clamp head that also plugged in to a
mains socket and have the pic calculate true RMS power.
Does anyone know of a unit that does this properly?

Bob

This is true - but don't most PSUs at least try to have a power factor of 1?

That leaves motors and old style tube lights.

I expect the problem was that many people don't have a 13A socket next to
the meter.

However, seeing as the base unit plugs in, if they used an unregulated AC
wallwart, perhaps with some extreme cleverness, they could achieve high
accuracy time synchronisation between the clamp unit and the base unit,
then the clamp could send a current sample set with timestamps and the base
could take a high resolution sample of the voltage profile.

It would be an interesting exercise...

Cheers

Tim

Tim S wrote:

ARWadsworth coughed up some electrons that declared:

Have a couple of MAX232 RS232 converters, so I'll see what it does later.
The real fun will be to see if it accepts commands...

The CC128 specifically says "this version does not listen for incoming
data" whether that means the Classic model does, I don't know.

http://www.currentcost.com/cc128/xml.htm

Andy Burns coughed up some electrons that declared:

Tim S wrote:

ARWadsworth coughed up some electrons that declared:

Have a couple of MAX232 RS232 converters, so I'll see what it does later.
The real fun will be to see if it accepts commands...

The CC128 specifically says "this version does not listen for incoming
data" whether that means the Classic model does, I don't know.

http://www.currentcost.com/cc128/xml.htm

Thanks for that link - very interesting.

They missed a trick - it should be possible to at least program the time and
unit cost into the device.

I think the clamp TX is the most interesting bit. The base unit could be far
smarter. Also I notice, it's not very flexible in terms of funky unit cost
profiles.

On Sun, 31 May 2009 08:25:09 UTC, Tim S wrote:

Bob Minchin coughed up some electrons that declared:

I can't see the value for logging the data from Current Cost units apart
from the initial technical challenge. With so many domestic loads being
non resistive, and these units not taking a phase reference, they are
bound to be inaccurate. Yes they will give a relative indication to help
track down wasted power but that is about all they are good for. It
would be so easy to have a smarter clamp head that also plugged in to a
mains socket and have the pic calculate true RMS power.
Does anyone know of a unit that does this properly?

This is true - but don't most PSUs at least try to have a power factor of 1?

Well, if you have the right sort of meter, theer's always this:

http://offog.org/code/electricity.html

--
The information contained in this post is copyright the
poster, and specifically may not be published in, or used by
http://www.diybanter.com

On Sun, 31 May 2009 09:36:48 +0100, Tim S wrote:

The CC128 specifically says "this version does not listen for incoming
data" whether that means the Classic model does, I don't know.

I don't think any of them accept commands, they spew out the data on a
regular basis.

They missed a trick - it should be possible to at least program the time
and unit cost into the device.
snip
Also I notice, it's not very flexible in terms of funky unit cost
profiles.

Average Joe Blogs won't be interested in plugging it into their PC or
doing fancy cost unit profiles (it does E7). Those that do want that will
have the skills to manipulate the raw data provided.

--
Cheers
Dave.

In article ,
Tim S writes:
Bob Minchin coughed up some electrons that declared:

I can't see the value for logging the data from Current Cost units apart
from the initial technical challenge. With so many domestic loads being
non resistive, and these units not taking a phase reference, they are
bound to be inaccurate. Yes they will give a relative indication to help
track down wasted power but that is about all they are good for. It
would be so easy to have a smarter clamp head that also plugged in to a
mains socket and have the pic calculate true RMS power.
Does anyone know of a unit that does this properly?

I made one about 25 years ago, but it only generates a power (Watts)
output, and not any long-term integration (total energy use).

Might be able to modify one of the plug-in ones to use the sense
coil/clamp. I did try opening one of my plug-in ones to see how
it did the sensing, but even with the case screws removed and the
two pieces of the case slightly separated, something was still
holding it together which seemed like it needed enough force it
would break, to I chickened out of opening it at that point, not
wanting to break it.

This is true - but don't most PSUs at least try to have a power factor of 1?

I don't think the consumer quality ones do, but I haven't bought
one recently. Industrial rack-mount ones do (at least, quality
ones), as it's rather important if you have 1000 of them in a
data centre.

That leaves motors and old style tube lights.

and CFLs, and wall-warts.

I expect the problem was that many people don't have a 13A socket next to
the meter.

However, seeing as the base unit plugs in, if they used an unregulated AC
wallwart, perhaps with some extreme cleverness, they could achieve high
accuracy time synchronisation between the clamp unit and the base unit,
then the clamp could send a current sample set with timestamps and the base
could take a high resolution sample of the voltage profile.

It would be needed at the sensor end.

It would be an interesting exercise...

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

Andrew Gabriel coughed up some electrons that declared:


It would be needed at the sensor end.

Not necessarily. If the base unit could synchronise time (delta time, not
absolute) with the sensor over the 433 link, at least to the millisecond
level, the sensor could send a batch of current readings with timestamps to
the base.

The base being driven from an unregulated AC wallwart would take a series of
hi res voltage readings with timestamps and, having found the intersection
of current readings and voltage readings, could in a leisurely manner do
the maths.

It assumes:

1) You can achieve the timing accuracy with a weedy microcontroller - I
think you could manage mS without any problem.

2) You can time lock over a 433MHz link to the same resolution - not sure.

3) You assume that your wallwart transformer is maintaining a stable ratio
bewtween mains voltage and output voltage and the waveform comes through
largely uncorrupted.

Note - I didn't say it would work, just that it would be an interesting
exercise

Cheers

Tim

Tim S wrote:
Andrew Gabriel coughed up some electrons that declared:


It would be needed at the sensor end.

Not necessarily. If the base unit could synchronise time (delta time, not
absolute) with the sensor over the 433 link, at least to the millisecond
level, the sensor could send a batch of current readings with timestamps to
the base.

The base being driven from an unregulated AC wallwart would take a series of
hi res voltage readings with timestamps and, having found the intersection
of current readings and voltage readings, could in a leisurely manner do
the maths.

It assumes:

1) You can achieve the timing accuracy with a weedy microcontroller - I
think you could manage mS without any problem.

2) You can time lock over a 433MHz link to the same resolution - not sure.

3) You assume that your wallwart transformer is maintaining a stable ratio
bewtween mains voltage and output voltage and the waveform comes through
largely uncorrupted.

Note - I didn't say it would work, just that it would be an interesting
exercise

Cheers

Tim
Much easier to do the measurements at one point and there is mains power
for the processor. many samples of the both waveforms are necessary as
the voltage 'flat tops' regularly - or at least it does here. Just have
a look with a 'scope (and suitable probe!!) sometime.
So many domestic devices with SMPSUs these days to blame.

Bob

Bob Minchin coughed up some electrons that declared:

Tim S wrote:
Andrew Gabriel coughed up some electrons that declared:


It would be needed at the sensor end.

Not necessarily. If the base unit could synchronise time (delta time, not
absolute) with the sensor over the 433 link, at least to the millisecond
level, the sensor could send a batch of current readings with timestamps
to the base.

The base being driven from an unregulated AC wallwart would take a series
of hi res voltage readings with timestamps and, having found the
intersection of current readings and voltage readings, could in a
leisurely manner do the maths.

It assumes:

1) You can achieve the timing accuracy with a weedy microcontroller - I
think you could manage mS without any problem.

2) You can time lock over a 433MHz link to the same resolution - not
sure.

3) You assume that your wallwart transformer is maintaining a stable
ratio bewtween mains voltage and output voltage and the waveform comes
through largely uncorrupted.

Note - I didn't say it would work, just that it would be an interesting
exercise

Cheers

Tim
Much easier to do the measurements at one point and there is mains power
for the processor.

I agree - *if* you have a socket near the meter...

I do here (Pembury) but in Robertsbridge the meter is outside, which is
common with many properties. I suspect the designers conceeded that a large
portion of th users wouldn't be able to source a direct connection, short
of a pin in the cable.

Although having said that, I wonder how well a capacitative pickup would
work - with a sticky electrode on the sheath of each meter tail?...

many samples of the both waveforms are necessary as
the voltage 'flat tops' regularly - or at least it does here. Just have
a look with a 'scope (and suitable probe!!) sometime.
So many domestic devices with SMPSUs these days to blame.

Bob