Using DS10a with CRMagnetics current switch

[SteveQ]

I am using a CR Magnetics CR3110 / DS2406 / xap one-wire network to monitor my electric baseboard heat. Homeseer creates a logfile of ON/OFF times.
I use the circuit contributed by Michael McSharry and posted to the Homeseer board by Rocco( http://board.homeseer.com/showthread.php?p...341#post627341)

This circuit is working OK but I would like to modify it and use it with a DS10a (wireless door/window sensor). This would give me a wireless current sensing device.
Is it feasible to use a transistor in place of the DS2406 and use the transistor to switch the DS10a ON/OFF.

My searches did not find anything. Does anyone have any experience in this area? I would appreciate any suggestions.

Steve Q

 

[BraveSirRobbin]

"Off-hand" I don't see why not. That circuit is converting the AC from the current sensor to a DC voltage output.

You may have to fiddle with the resistor value to make sure the transistor switches properly. I've seen schematics in the past that just wire the transistors' collector and emitter to a DS10a (NPN type, something like a 2N3904) and people reported it worked.

Let's see if Rocco or Michael reply! <_<

 

[deranged]

I connected a cr9321 npn directly to a ds10 and it works great, NO resistors or extra parts.

I use it to detect when my electric heater is on in the garage.

StevenE

 

[SteveQ]

I connected a cr9321 npn directly to a ds10 and it works great, NO resistors or extra parts.

I use it to detect when my electric heater is on in the garage.

StevenE

This sounds great. I will need the split core version (CR9380 -NPN available from DigiKey - $30.28).
A little bit pricy, but it will keep things simple and since I only need 1 or 2, it may be the way to go.
I intend to use this on my water heater.

Thanks,
Steve Q

 

[BraveSirRobbin]

That's a pretty cool device (the CRMagnetics sensor with included transistor output).

 

[SteveQ]

"Off-hand" I don't see why not. That circuit is converting the AC from the current sensor to a DC voltage output.

You may have to fiddle with the resistor value to make sure the transistor switches properly. I've seen schematics in the past that just wire the transistors' collector and emitter to a DS10a (NPN type, something like a 2N3904) and people reported it worked.

Let's see if Rocco or Michael reply!

The addition of a 2N3904 transistor worked perfectly. It will directly switch a DS10a.
This is a great way to wirelessly monitor a baseboard heater.

Steve Q

 

[politics123]

"Off-hand" I don't see why not. That circuit is converting the AC from the current sensor to a DC voltage output.

You may have to fiddle with the resistor value to make sure the transistor switches properly. I've seen schematics in the past that just wire the transistors' collector and emitter to a DS10a (NPN type, something like a 2N3904) and people reported it worked.

Let's see if Rocco or Michael reply!

The addition of a 2N3904 transistor worked perfectly. It will directly switch a DS10a.
This is a great way to wirelessly monitor a baseboard heater.

Steve Q

Okay, You guys piqued my interest. I wanted a way to monitor Hot Water heater, and this looks like a pretty inexpensive option (and safe, too... I wasn't thrilled with a wired solution leading from high voltage back to the ELK). I'm not smart enough to build a circuit; was hoping you guys could confirm how to do this:

1) Buy DS10a and an X10 wireless receiver. (I already have an ELK--> X10 interface) [ a couple bucks each + shipping ]
2) Buy a cr9321 NPN from digikey [ $23.60 ]
3) Program an ELK zone to match the house code for the DS10a
4) Cut the magnet from the DS10a and directly wire the CR9321 leads to the DS10a
5) Write an ELK RP rule to speak "Heating Water" whenever the DS10a zone is tripped

Sound about right?

Thanks!
Michael

PS -- The CR9321 seems to be 240v specific. I guess that means I couldn't use the same trick to track how often the refridgerator motor runs? (120v) Or how often the water pump activates (120v)?

 

[SteveQ]

I think your approach will work fine, but I would suggest:

1.) Use the split core CR9380, otherwise you will have to disconnect a wire from the water heater and feed it through the core of the CR9321.

2.) If you don't have a wireless receiver, you could use the X10 powerflash module in place of the DS10A to "put the X10 signal on the powerline". (also, you cannot use a standard X10 wireless receiver with the DS10A - it uses a different frequency; you need a special receiver such as the W800)

I am not familiar with the ELK so I can't comment on how to program it.

Steve Q

 

[eufreka]

I think your approach will work fine, but I would suggest:

1.) Use the split core CR9380, otherwise you will have to disconnect a wire from the water heater and feed it through the core of the CR9321.

2.) If you don't have a wireless receiver, you could use the X10 powerflash module in place of the DS10A to "put the X10 signal on the powerline". (also, you cannot use a standard X10 wireless receiver with the DS10A - it uses a different frequency; you need a special receiver such as the W800)

I am not familiar with the ELK so I can't comment on how to program it.

Steve Q

Can you use something like this EZIO8SA Input/Output Interface Module to monior 7 CR9380 devices?

 

[SnyperBob]

1.) Use the split core CR9380, otherwise you will have to disconnect a wire from the water heater and feed it through the core of the CR9321.

Steve Q

Which do you guys recommend? Digikey has three listed:
CR9380-ACA
CR9380-NPN
CR9380-PNP

It appears the NPN and PNP versions work with 120 volts. The ACA version is 240 Vac? Can someone confirm this, I don't want to post false info and cause someone problems

 

[mimitche]

Cool idea.

I don't use X10 so I was thinking about using a NX-650 wireless door/window transmitter (http://www.automatedoutlet.com/product.php?productid=911&cat=377&page=1) to connect the CR9380 to my Elk M1. The NX-650 has an terminal strip for using hardwire contacts instead of the internal reed switch so I'm assuming it will work just as well.

 

[electron]

Great idea, I have a bunch of DS10A's left, I wouldn't mind using them to monitor some more appliances. Wish we could buy these sensors in bulk and save some money. Snypez, if you find out which one is the right model, don't hesitate to post here! Thanks!

 

[TonyNo]

I'd be in for a group buy...

 

[Photon]

SteveQ said, "I intend to use this on my water heater."

If this data is to be used to calculate energy consumption, I think it will require two monitors; one for the upper and another for the lower heating element.

Thanks for the idea, Steve. For as long as we've been married, one of us asks the other if we checked to see if the electric range is off as soon as we are well out of town. Your idea connected to my Elk-to-be look to me like the solution. The checklist by the back door sure didn't work. I thought I would be working on an infra-red sensor to report the answer, but your idea just seems so right.

 

[mimitche]

Hmmm, if I add one of these to my electric dryer's cord I could have Elk announce that its time to fold the laundry, right?

...Although being prompted to fold laundry might end up ranking pretty low for WAF... :unsure: