Powerline Current Sensor

[JeffVolp]

I see people looking for some easy means of monitoring whether a device is on or off.  If there appears to be enough demand for something like that, I am thinking about offering one.  It would simply send a "X STATUS ON" or "X STATUS OFF" when current through it is switched on or off.  "X" would be a user-programmable house/unit code.  Since many devices pull a continuous current when off, it would have some means of ignoring the quescent current.  It might also include a query mode where it would send the status in response to a "X STATUS REQUEST".  It would NOT control power like an appliance module.

Thoughts?

[HA Dave]

I see people looking for some easy means of monitoring whether a device is on or off.  If there appears to be enough demand for something like that, I am thinking about offering one. 

About three years ago glt posted about a similar device. I am not sure his links still work.. or that his post is overly clear.

Since his microwave would mess up his audio receiver and cause loud static. He used a special coil and circuit to determine if power was being used by his microwave. When the microwave would draw enough power (drawing more than the clock) the device would turn OFF the audio receiver while the microwave was ON.

A pre-made device like this... may have some marketable uses... for determinding if manually controlled/operated devices are being used. But, I think what many users want/need is a way to know if a X10 device (light switch) has been manually turned on. Which as we know... can be done with different switches... instead of the cheapie X10 ones.

What might be handy is a software that allows the HA PC to remember the status of ALL house/unit codes. But... didn't bitman just post that. But combining the two... could allow a user to know how often or how much time his furnace is running while away. Or how late a teen is watching a TV.

Or even to get an email notice if the sump pump kicks ON... Are you considering a plug-in type device? That would sound good to me.

[JeffVolp]

Are you considering a plug-in type device?

Yes, about the size of a normal X10 module.  It would be mainly to address the problems people have determining the state of electronic devices that have IR toggle ON/OFF control so they can be properly automated.  My wag is that it would be about $40 in kit form.

Jeff

[Brian H]

Maybe a nice addition to ones setup.
I have also seen a few current sensors used with a PowerFlash; but that is not a nice neat package.

[dave w]

Maybe a nice addition to ones setup.
I have also seen a few current sensors used with a PowerFlash; but that is not a nice neat package.

Yeah Brian, I sorta remember that also. Seems like it was on this forum. I think the current sensors was in neighborhood of $30-$40.

I wanted to try a simple torrid arrangement with the secondary windings on the torrid coupled to a PowerFlash. I don't know what input sensitivity on a PowerFlash is.

[HA Dave]

... about the size of a normal X10 module.  It would be mainly to address the problems people have determining the state of electronic devices that have IR toggle ON/OFF control so they can be properly automated.  My wag is that it would be about $40 in kit form.

AWESOME!

[Brian H]

The folks over on Cocoontech used a CT800 Module that has a set of dry contacts to trigger a PowerFlash.
Looks like that core triggers a set of contacts and I believe may come in different trip currents.

Link to How-to:
http://www.cocoontech.com/portal/articles/tutorials/home-automation/49-how-to-monitor-the-status-of-your-appliances-using-current-sensors

Sensor data:

http://www.mamacsys.com/ct_800_805_810_815_features.html

Jeff I still like your idea for a new product. I think it could be a good addition to many installations.

[dave w]

Jeff I still like your idea for a new product. I think it could be a good addition to many installations.

YES!! I also. Especially if there would be a way to null out quiesent current.

[HA Dave]

Especially if there would be a way to null out quiesent current.

I agree with dave w and Brian H. Maybe a switch (or pin placement)... that would cause/allow the Sensor to overlook current draw of [say] 10 watts or less. That way it could be used unswitched to sense even a very low wattage CFL or LED light. Or switched to overlook the vampire draw of a TV or DVD player [that has always on electronics for the IR and clock].

I am excited about this Jeff!

[JeffVolp]

I agree with dave w and Brian H. Maybe a switch (or pin placement)... that would cause/allow the Sensor to overlook current draw of [say] 10 watts or less. That way it could be used unswitched to sense even a very low wattage CFL or LED light. Or switched to overlook the vampire draw of a TV or DVD player [that has always on electronics for the IR and clock].

I am excited about this Jeff!

To deal with the quescent power, it would require a power cycle in the first N seconds from off to on to back off.  It would then calculate the threshold somewhere between those two values, and store it in flash memory.  If it was to be used on another device, it could be reset by a X10 command in the first couple seconds after being plugged in.

Someone had mentioned using it for something like a sump pump.  To cover a 5A to 10A range, I don't think it would be feasible to monitor current draw from a very low wattage device.  Without doing some design work, my WAG would be the minimum threshold would be in the 5W to 10W area.

Jeff

[dave w]

TOL (thinking out loud)

This is getting interesting. A while back I was thinking of putting a 120V AC coil relay across the compressor of our refridgerator and coupling the closure from the relay to a PowerFlash.
Why you ask?
Well I accidently left the freezer door slightly ajar when leaving for the store. Nothing thawed since I was not gone long, but it planted the seed to monitor compressor run time and have Homeseer send email or make announcement if run time exceeds some preset, thus indicating a problem.
I decided not to do it,  as regridgerator is under extended warrenty, but this device could be used to detect all kinds of "Houston we have a problem" scenarios with out hacking the device you want to monitor.

[Charles Sullivan]

TOL (thinking out loud)

This is getting interesting. A while back I was thinking of putting a 120V AC coil relay across the compressor of our refridgerator and coupling the closure from the relay to a PowerFlash.
Why you ask?
Well I accidently left the freezer door slightly ajar when leaving for the store. Nothing thawed since I was not gone long, but it planted the seed to monitor compressor run time and have Homeseer send email or make announcement if run time exceeds some preset, thus indicating a problem.
I decided not to do it,  as regridgerator is under extended warrenty, but this device could be used to detect all kinds of "Houston we have a problem" scenarios with out hacking the device you want to monitor.

Alternatively you can connect the primary of a 6 or 12V AC wall-wart transformer across the line to be monitored and the secondary to the voltage input of a Powerflash.  (A DC wall-wart doesn't work very well as it can take a long time for the high impedance input of the Powerflash to drain the filter caps in the wall-wart when the power goes off.)

But a current sensor would be neater and easier.