As part of my recent dive back into home automation I decided it would be cool (and once again practical) to be able to receive an alert that the washing machine has finished washing a load of clothes.
This wasn’t something I blindly jumped into. There is plenty of information on the Web documenting how others have already done this with various home automation setups. As it turns out, at least with our washer, Indigo 6, and an Aeon Labs DSC06106-ZWUS – Z-Wave Smart Energy Switch it can be remarkably easy.
But before we can determine if the washing machine has turned off we first need to determine whether or not it is on.
In order to do this I created a boolean variable in Indigo named WasherOn that is set to false by default.
Next, I created a trigger that fires when the smart energy switch senses that the load on the switch is greater than 4 Watts. In this case I had already determined that the washer draws slightly more than this in the early stage, while it fills up with water.
When the washer draws more than 4 Watts the trigger will change the value of WasherOn to true. At this point one could setup a notification of some kind but I didn’t think it would be very useful as the person most interested in the status of the washer is typically the same person that started it and loaded it with clothes, thus very aware that the washer is indeed on.
The next step is to create another trigger that simply fires when the energy load drops to 0 Watts. When that happens our system will then say, using a text-to-speech plugin and a Bluetooth speaker, that “the washing machine cycle has finished”. The color-changing LED bulb also flashes a couple of times as an additional indicator.
The final action of that trigger is to set the value of WasherOn to false. That’s it. There really isn’t much to this.
Of course, that’s with our washer. The load may vary widely between different washing machines and I suspect that some newer washers may always draw some small amount of power, though hopefully not as much as the 4 Watts that indicate our washer is on. However, that may be critical when setting your final trigger to determine when the washer has finished.
In addition, and this is an important point, you need to make sure that the smart energy switch you use is rated to handle the Amp rating for your connected device. The manual for our washer indicated that the washer should be on a 10 or 20 Amp circuit, which I assume means that the washer requires a 10 Amp circuit. The energy switch I’m using is rated for 15 Amp and so far everything appears perfectly fine.
Smart energy receptacles are also available, if preferred, and I’ve seen them on Amazon.com in both 15 Amp and 20 Amp versions.
It’s important to be aware of the fact that this is a switch and it can be turned on and off. As a result, it’s possible to interrupt the washer during a cycle though I can’t think of a practical reason for doing this and under the wrong circumstances it might even be possible (though probably not likely) that it could damage a washer.
To reduce the chance of problems I have this device set so it will not be displayed remotely (in the app or web interface).
So far I haven’t had a problem with the switch defaulting to an OFF state but, should that happen due to power outages or other problems, I do have a trigger (currently disabled) that will automatically switch it to ON any time it is detected as being OFF.
There is one problem I have yet to resolve and that’s adding the ability to track the status of the dryer. This method works well for just one load but once you have a load in the dryer then the dryer typically becomes the hold-up. Unfortunately, I don’t have a simple solution for my dryer yet. Some people have used door sensors but that’s not an option with our dryer – our door does not open automatically at the end of a drying cycle.
A vibration sensor might be an option but I have not found one that I consider both reliable and reasonably priced (yet). It’s still something that I’m considering.
At the moment there do not appear to be any Z-Wave 220 plugin modules available. It is possible to wire a sensor into a 220 line but I simply don’t want to mess with that type of circuit.
Ours is an electric dryer but someone using a gas dryer connected to a 110 line may have an easier task at hand.
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for the dryer… is there any sort of air flow sensor you could use? If so, you could have the sensor in the exhaust vent. Just a thought. Messing with 220 scares me, so I don’t blame you for trying different solutions.
That’s actually a good idea that I hadn’t considered but the weight, and required heat resistance, would probably eliminate the ability to use traditional Z-Wave modules (and they’d have to be rated for outdoor use). It may need to be a non-standard item and the contacts at the vent door itself would need to be very basic. Or… perhaps I could build a frankenmodule that involves using parts from a traditional door sensor and then finding a different way to sense the state of the door with heat-resistant materials. There seem to be several different ways to go about doing this. The hard part is figuring out what is the easiest and most reliable method to use with my dryer but at least I’m not locked into only one possibility.
Another thought… If the dryer has some sort of buzzer to indicate it is finished, maybe you could wire directly into that signal somehow.
Unfortunately it doesn’t. I’ve heard of people trying to do things with LEDs on dryers – again, also not a feature that ours has. Both are relatively basic and not modern, but they still work fine.