Recently moved into house that was built before neutral wire was required at the light switch. In my garage I have a wall switch that turns on the ceiling lights. I am adding an additional light over the work bench which I can plug into a smart plug.
What I would like to do is when I turn on the main ceiling lights also have that light come on. So somehow I need to detect when the main switch is turned on. or off for that matter. The ceiling and walls are all sheet rocked and thus no real way to run a neutral to the existing switch. I can obviously get to the box where the ceiling light is mounted which should have hot and neutral there plus the switch leg coming back from the switch. I don't want to just power up some smart device when the switch is turned on as there would be too much lag before it re-connects to the hub every time. So would have to be something that I can power up all the time and then detect when power is applied to the switch leg.
That isn't how those smart relays work. The old light switch would just tell them to turn on, basically a dumb button. The old switch doesn't cut power to the smart relay, so there should be virtually no lag.
There are a couple smart switches that do not require a neutral. I think the older Inovelli Red can do this? And I believe their new Blue are going to also? I think I am forgetting another one here.
If you have dimmable lights, you can use a wide variety of no-neutral dimmers. I went out of my way to use dimmable LED in my garage, and it is so nice to be able to dim them to let the dog out in the middle of the night or retrieve something out of the car without being blinded.
The upcoming Inovell Blue Series VZM31-SN will do this, as will the the Red Series LZW31-SN you mentioned, though you probably can't find those anywhere right now. The HomeSeer HS-WX300 and many (not all) Lutron Caseta and RA2 switches and dimmers are others I can think of, though Lutron requires extra hardware to work with Hubitat and may not be worth the expense for just one.
As you mentioned, I wouldn't rule out a relay, either--or smart bulbs with a remote/button device, which is definitely the easiest to install. I wonder if the "lag" concern was related to the fact that you may need to wait for the "switch: on" event to come in from the relay before the hub would know to turn on the second light, which may take a small or slightly-less-small amount of time depending on the device and your network. (There may be some that just send button events when the dumb switch is moved, too...IDK, but those may come in faster if so, and if they're both Z-Wave, then Association might make it faster but would definitely leave the hub out of the middle if that is a concern--though this would work with a switch/dimmer, too.)
I have used the GE/Jasco zwave (no neutral) switch in places where there is no neutral.
I have been pleasantly surprised by its dependability. No issues whatsoever.
Furthermore, no bypass required (so far). Even in one instance where the switch was powering just a simple LED BR30 bulb(one).
Thanks for all the suggestions. I had a ZEN51 I was hoping to save for another purpose, but decided to go ahead and use it on this application. And thus ran into a problem.
Hooked it all up on the bench and tested to make sure it was working the way I wanted. Hooked it into the light circuit. Could turn the lights on programmically but the wall switch did nothing. Checked wiring. Traced and rang out wiring. No problems. Maybe bad wall switch. Replaced that. No change.
Got to checking some more and when the wall switch is off there is about 10 volts on the switch leg. Goes to 120 when on just like it should. Can't figure out where that 10 volts is coming from. But it is enough to keep the ZEN51 from recognizing a switch change. Disconnected the ZEN wire and just touched it to the wire coming from the switch so it works, just won't work if there is any voltage at all on that wire it seems. Or if the voltage doesn't go to zero.
Got to hot to work on it anymore. Mid Missouri August heat in June here. So took relay out and mess with it some other time. Any ideas where I'm picking up that low voltage? With Breaker off the voltage is zero.
Many people have found Lutron Caseta devices to be wonderful devices. I have Caseta, Zigbee, and Zwave devices. The Caseta devices are the most reliable. It is not an inexpensive option as you need a Lutron Caseta Pro bridge to interface with Hubitat using a blazing fast Telnet connection that works well.
The Caseta dimmers typically do not require neutrals, but your lighting needs to be dimming capable (dimmable LEDs recommended). They also have switches as part of the Caseta line. Some of the switches require neutrals, others do not, so be sure to check.
Lutron Caseta uses a Clear Connect protocol which uses a frequency different than Zigbee and Z-wave, so there is no interference.
Another nice thing about Caseta is that if you need 3-way, 4-way or more, you install a single dimmer in the primary position, join all the traveler wires and then use Lutron Pico remotes in all the other positions. It make the installation process much simpler than trying to wire three way and four way switches. The remotes pair directly with the dimmer as well as with the bridge, so they will continue to control the lights even if the bridge is off-line.
Since you are starting with a new installation, I highly recommend that you check out Lutron Caseta. If the price is higher than you can afford to do everything at once, purchase the Pro Bridge and dimmers for your most used rooms. Then add a few more every couple of months until you have everything done.
BTW- no matter which switches or dimmers you chose, I highly recommend adding a couple of motion detectors in the garage so that lights will not time out and leave you in the dark. That can be both disconcerting and potentially dangerous. I have had that happen to me when I used a single motion detector switch.
I also want to encourage you to consider Lutron Caseta dimmers and switches. You will need the Caseta Pro Hub which integrates with Hubitat. Although a bit pricey, Lutron Caseta devices are rock solid and worth the premium price, in my opinion.
I am, and was in the old house, completely satisfied with my Zwave and Zigbee switches, etc. connected directly to HE. Not really interested in another hub/bridge such as Lutron. I realize that is a great product but just not for me.
We also don't need any dimming. Just not our lifestyle. My garage lights are all fixtures with permanent LED's that are non-dimmable. So a little leery about the no-neutral switches as they seem to all be dimmable. The Inovelli Blue looks promising, but it's not available yet it seems. The The HomeSeer HS-WX300 really looks promising as it can be set to be non-dimmable. But I don't see that model on the compatible device list. I read the instructions as to how to set it to non-dimmable and think they may have a little mistake there. It says to turn OFF power then push a sequence of buttons and watch the LED's. Hummm, power off and watch LED's.
Anyway, this is not a rush project so will work on it as I have time. Still puzzled on that 10 volts on the switch leg when the switch is off.
I agree that for in a garage, dimmable lighting might not be necessary. However, with today's escalating energy costs, using dimmable LEDs might make sense in some locations. For example, I have my outdoor lights functioning at 50% brightness unless my outdoor motion detector picks up motion. Then it goes to 100%.
Likewise, if you go into the bathroom to use the toilet, shower, or brush your teeth, you might not need the lights at full brightness. However, if you are shaving or your spouse if putting on makeup, you will want all the light you can get.
In your family room, if you are watching TV or streaming, you might want a lamp on at a low level for background lighting. However, if you are reading, you might need full brightness.
I encourage you to evaluate the various situations and purchase the most suitable device for your application. I have dimmers in most places, but do have some fixtures in the laundry and kitchen that are on switches as I do not ever dim them.
Outside lights are never on unless we turn them on or motion detect and its only to let the dog out or to let someone in. And then they are only on 5 minutes.
I don't even do smart lighting in the bathrooms. Never needed motion lighting there. And in reality the time spent in bathroom is rather short.
And etc, etc. Just the way we live and operate. We are more on control than automation. Usually want to turn on lights with Alexa. I do have automations to do things when we are gone, bedtime routine, wakeup routine. Alarm routine which turns on all lights. Just have never needed dimming or particularly want it for any reason.
I had a lot more lights on smart switches in our old house, but having to cut back here as this house is older and there are no neutrals in the switch boxes. But have been able to make the ones work that I need to, other than the garage. And I don't really need any reason to have the garage lights come on automatically, or at least haven't run across any scenario for that. As stated in my original post, I just want to know when the switch is thrown so that I can turn on another light. But it won't be that critical.
I wonder if the "lag" concern was related to the fact that you may need to wait for the "switch: on" event to come in from the relay before the hub would know to turn on the second light, which may take a small or slightly-less-small amount of time depending on the device and your network. (There may be some that just send button events when the dumb switch is moved, too...IDK, but those may come in faster if so, and if they're both Z-Wave, then Association might make it faster but would definitely leave the hub out of the middle if that is a concern--though this would work with a switch/dimmer, too.)
