Appliance monitoring circuit w/relay output

GadgetNut

New Member
For those of you that have basic electronics kit building skills and interested in non-intrusuve monitoring of electrical appliances (washer, dryer, etc.) or other electrical devices, I've put together a current sensing circuit using a CR magnetics current transformer and a modified Velleman Light Sensing Relay kit. The arrangement is more sensitive (about 75W/.65A to trigger) than the current transformer + X10 Powerflash solution and has a relay contact output.

The basic components run about $25 or so less enclosure.

The writeup is at http://www.box.net/public/58kq84m2vv

I'd be happy to have it added to the How To section of there is interest.
 
This looks to be a good way to get a dry contact output from the CR3110. The hysteresis band is what makes it attractive. I just have some idea to supplement it.

The first is to direclty connect a DS10A to the relay outputs for those that want RF rather than hardwired input to their HA software. This eliminates a need for low voltage wire from the appliance back to the HA interface.

A correlary thought is to use the hawkeye dusk/dawn hack rather than the velleman kit and go directly to RF without the relay interface. This will still need so design tweaking to match the PIR input of the hawkeye with the DC input from the CR3110 side.

The second is to package the unit so that it is wired to the appliance as an extension cord. It would have a 3 prong receptical for the appliance and a wire and 3 prong plug to connect to the wall. Inside the package will be the 12VDC power source or circuit to make it from the 120VAC as well as the routing of the single wire through the CR3110.

I believe that CR Magnetics has released a product a year or two ago that has a DC or relay contact output to achieve the same type of on/off monitoring capabilty. I find the CR Magnetics site hard to naviagate so it could be there and I just did not find it.
 
Michael McSharry said:
I believe that CR Magnetics has released a product a year or two ago that has a DC or relay contact output to achieve the same type of on/off monitoring capabilty. I find the CR Magnetics site hard to naviagate so it could be there and I just did not find it.
I think this is the current sensing relay you're thinking about, CR4395.

The Pod
 
Michael McSharry said:
This looks to be a good way to get a dry contact output from the CR3110. The hysteresis band is what makes it attractive. I just have some idea to supplement it.

The first is to direclty connect a DS10A to the relay outputs for those that want RF rather than hardwired input to their HA software. This eliminates a need for low voltage wire from the appliance back to the HA interface.

A correlary thought is to use the hawkeye dusk/dawn hack rather than the velleman kit and go directly to RF without the relay interface. This will still need so design tweaking to match the PIR input of the hawkeye with the DC input from the CR3110 side.

The second is to package the unit so that it is wired to the appliance as an extension cord. It would have a 3 prong receptical for the appliance and a wire and 3 prong plug to connect to the wall. Inside the package will be the 12VDC power source or circuit to make it from the 120VAC as well as the routing of the single wire through the CR3110.

I believe that CR Magnetics has released a product a year or two ago that has a DC or relay contact output to achieve the same type of on/off monitoring capabilty. I find the CR Magnetics site hard to naviagate so it could be there and I just did not find it.

I was thinking along the lines of a dry contact ouput when I thought of using the Velleman kit, so X10 RF wasn't considered, but the DS10a and a modified Hawkeye probably a good approach.

There is a good article on how to interface a contact closure to the Hawkeye at http://www.geocities.com/ido_bartana/modif...wkey_sensor.htm

The CR Magnetics relay runs about $80 and its not clear how much sensitivity it has. Too expensive to buy and try.
 
Back
Top