CT sensor purchase fail?

That Functional Devices ribxgta current sensing switch is a cool product. I plan on using something like this for my washer and dryer to make whole house announcements ("washer cycle complete", "dryer cycle complete") and such.

However I have a "high efficiency" front loader washer and dryer. The washer spin rate varies a lot, sometimes stopping completely for a while. I suspect the current consumption at these points is very low, maybe 0.05A (~5 watts) but I'm guessing without measuring it. These current sensing switch products trigger at a minimum of 0.35A.

In cases like these I can think of two ways to make it work:
1) Increase the turns count (wire loops through the transformer) as necessary to always stay above the minimum threshold. I might need 5 to 10 turns.
2) Use a more sensitive device (if available) or a discrete CT with the ACS712 Low Current Sensor.

Something to think about if you also have front loaders.
 
Mr Spock said:
That Functional Devices ribxgta current sensing switch is a cool product. I plan on using something like this for my washer and dryer to make whole house announcements ("washer cycle complete", "dryer cycle complete") and such.

However I have a "high efficiency" front loader washer and dryer. The washer spin rate varies a lot, sometimes stopping completely for a while. I suspect the current consumption at these points is very low, maybe 0.05A (~5 watts) but I'm guessing without measuring it. These current sensing switch products trigger at a minimum of 0.35A.

In cases like these I can think of two ways to make it work:
1) Increase the turns count (wire loops through the transformer) as necessary to always stay above the minimum threshold. I might need 5 to 10 turns.
2) Use a more sensitive device (if available) or a discrete CT with the ACS712 Low Current Sensor.

Something to think about if you also have front loaders.
Click to expand...
Depends on how long the longest break is between spins... I think you need to monitor the load the first time it runs, then adjust. For instance, while it does appear to completely stop for a moment to fill, drain, whatever - you should be able to figure out the longest amount of time it stays off, and wait for that period to time out before making announcements. Of course it'd be nice to know the second a cycle is finished, but that would probably require hacking into the control board a little.
 
Installed the sensor on the dishwasher over the weekend. Added the sensor output to an iolinc sensor input for a totally self contained wiring solution... though i could very well could home run it to my elk if i needed to. It was very interesting logging the output over a few cycles. The pattern was easy enough to pickup. The most interesting was the dry cycle. It heated and then turned off every three minutes for thirty minutes. Then after the final heat and turn off cycle it delayed 12 minutes before the machine signaled cycle complete. Maybe a cool down? Any event it works great. Now to decided over voice announcements or just my standard text message. Decisions decisions.
 
Mr Spock said:
That Functional Devices ribxgta current sensing switch is a cool product. I plan on using something like this for my washer and dryer to make whole house announcements ("washer cycle complete", "dryer cycle complete") and such.

However I have a "high efficiency" front loader washer and dryer. The washer spin rate varies a lot, sometimes stopping completely for a while. I suspect the current consumption at these points is very low, maybe 0.05A (~5 watts) but I'm guessing without measuring it. These current sensing switch products trigger at a minimum of 0.35A.

In cases like these I can think of two ways to make it work:
1) Increase the turns count (wire loops through the transformer) as necessary to always stay above the minimum threshold. I might need 5 to 10 turns.
2) Use a more sensitive device (if available) or a discrete CT with the ACS712 Low Current Sensor.

Something to think about if you also have front loaders.
Click to expand...

Do you have an indicator light that goes on when the dryer has completed its cycle?
 
I've got the whirlpool model of front loader washer & dryer. Very typical units I've seen in many places. When the spin pauses the length of time varies a lot. On a normal wash cycle it might only be 3 or 4 seconds. Meanwhile nothing else is happening other than a couple of indicator LEDs and whatever power the internal logic circuits are drawing. However if I use the Auto Soak cycle it can pause for minutes of time. Again only a couple of LEDs are on.

For the dryer I have the option of using the built in sounder, which I never use. With the sounder off when the cycle is complete it seems to completely turn off. I see the dryer as being the much easier of the two to make this work.

Next time I do laundry I'll break out my Kill-a-Watt and make some observations and post back here.

iostream212 I'm curious if the pausing your observing will cause you any trouble in determining when your dishwasher cycle is complete?
 
I can't speak to these sensors, but I'm using an Insteon SynchroLinc and I see pauses in my washer's cycle as long as 5 minutes. I just wrote a macro that waits until it's been off for at least 6 minutes and then tells me. That's plenty of precision for my purposes.

I tried lowering the threshold for "on" but it greatly increased the number of on-off cycles. I didn't feel like the additional signals were adding anything to the eventual conclusion.
 
If monitoring your washer and dryer is what your after, this is what I did. I have the whirlpool duet. I taped a photoresister over the done light on both the washer and dryer. Added a resister to get my analog/digital output measurements and thats it. When the done light came on, my board saw the voltage change and I got an email. The system was very reliable.

I have since taken the system out because I moved and my washer/dryer are on the first floor instead of the basement. I am using the same photoresister to let me know when if a remote outlet is turned on or not. I purchased a $15 outdoor remote controlled power outlet from home depot. It has a indicator light which tells me if the outlet is powered up or not. I have it in my new basement which is plugged into a humidifier. I have it run on a schedule or try to considering how humid it has been so far this summer.
 
iostream212 said:
Thanks for the info mobileme. To clarify you used the same sensor and got it working with this breakout board?
Click to expand...

I just want to recant my statement about the breakout board I commented on. I was mislead about this board functioning. I ended up creating a diode bridge with a parralle resister and capasiter to get the voltage I wanted. Keep in mind that I just wanted to know if a device was on or off so I didn't need to measure power usage. If you want more info about how I did it, shot me a message.
 
No issue determining cycle end. I did a few test runs on the various modes and took a look at the log after. I used that info to create the sensing program. It was pretty predictable and very precise... only 1 second difference in expected log times. The longest off time during cycle for this dishwasher is 2 minutes. So if the sensor goes off I wait 2 minutes. If it is still off I wait 3 mins additional. Then it is cycle end if the sensor is still off at the five minute mark, else it resets if the sensor pops on.
 
Ok, so your not looking for somewhat precise end of cycle timing. I want to know within about 5 seconds of true end of cycle. Everyone has their own tolerances for this sort of stuff. I guess I'm wanting better accuracy than most.

I really like the idea of taping a photo-sensor to the LED "cycle complete" light (thanks MobileMe). But I also need very high WAF in the new house. If I go this route I'd use a optoisolator switch connected to the circuits driving the LED and then feed that output to my panel. Downside is I have to take the two units apart which could lead to warranty problems.
 
What is WAF? The reason I did the photoresistor is because I didn't want to void my warranty which as it turns out I needed very badly. I did have a hard time getting the combination to make this work and did consider cracking open the machines. I'm glad I didn't for two reasons. Warranty is one and the other is the entire front panel is not module at all. It would have been a huge disaster if I did.
 
WAF = Wife approval factor... a constant battle in the world of home automation. >_>
I totally understand wanting to know the second the appliance finishes. In my case the dishwasher waits 10 minutes after cycle end before signalling cycle complete. So my 2 minute tolerance is still beating the dishwashers signalling by 8 minutes.
I opened up a old dishwasher a year ago and the signalling board looked like it was dipped into a protection material which made it very difficult to access wiring. Definitely do your research before ripping that beast open.
 
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