Light switch wifi and old school (upgrade existing)

Hey there,

maybe this topic is already discussed here an I simply did not really find the correct answer, but if so please be so kind to just tell me where.

My question is what is the best way to upgrade an existing light switch to a smart one.
It should be able to switch independet of each other from the existing wall switch and via wifi.
As I think there should only be a “box” (whicht might be the real power switch) which reacts to wifi and also to the wall switch. So I want to be able to turn on the light by wifi even if the wallswitch is off.

Is there any cheap solution for this?

If it is not too expensive I could also use a complete solution with the wall switch integrated.

Thanks a lot!

I believe what you are after is a dry contact if you are looking to keep the “old fashioned” light switches in place of the wall. Something to consider is how much room you have in the gang box, at most I have a few double gang boxes and it was…lets say challenging… as I replaced the light switches which required more room.

I’ve used one of their products to control my garage door.

Another option is to leverage WiFi light bulbs, but they can not be controlled if the switch on the wall kills power to the light.

And I haven’t tried them but search on this forum for shelly, cheap and sounds like exactly what you are looking for
Oh and welcome to the OpenHAB community!

I use TP-Link Kasa WiFi light switches and plugs. They’re priced well (in Canada) and have been ultra-reliable for me. Plus, openHAB controls them locally, so no need for TP-Link’s cloud control after you’ve set them up. You can go as far as denying them Internet access via your router settings if you want to completely cut them off from the web, but I prefer to let Google Home control them directly for those times when is down.

About any solution to allow for retrofitting. There’s ZWave, Zigbee and WiFi actuators available to allow for attaching a switch so even with OH down you can switch the lights (the actuator of course needs to have permanent power).

I’m using a few of the Sonoff touch in my house, take a look:

To integrate with openHab and connect to MQTT, I flashed it with the tasmota firmware.

Shelly 1 and Sonoff are popular choices for this.

On big question is “where are you located?”
The US has drop-in replacement smart switches but some other countries do not and there are addon modules.
IMO Wi-Fi, especially 2.4GHz is not the best solution for SmartHome due to interference possibilities. I personally use Z-Wave devices.

To add to this, I did have interference issues with one of my wifi switches (it was blocked by my refrigerator), but I solved it by installing a mesh router. If I started over then I’d definitely consider going with zwave everywhere, but in Canada a zwave lightswitch is about twice as expensive as the TP-LINK Kasa switches I use.

I just started looking a Zooz switches ( I would expect they sell to Canada too.

Yep, I’ve seen those for $45-55, but Kasas can be had for $30, and frequently go on sale for $20-25. There’s also the added cost of a zwave controller, but I didn’t count that since it can be useful for other purposes.

I would suggest that wifi is the easiest and least expensive option for lighting control, but zwave/zigbee is worth the investment if someone has aspirations to add other kinds of devices down the line (sensors, locks, etc.). Of course, in openHAB you can have the third option of “both”. :grinning:

Zigbee, as currently implemented, has the same interference possibilities as 2.4GHz Wi-Fi.

How much of a factor is this in real-world terms? I acknowledge that it’s a possibility, but I live in a condo building with many competing wifi signals, and the only issue I had was my own refrigerator (plus when I run the microwave).

I’m not downplaying your concern…if not for the cost, I’d absolutely pick zwave to remove the variable of 2.4GHz interference/congestion. I’m just wondering how much weight people need to give to it when cost is an important factor.

I work with a Wi-Fi system in a University environment. We provide 2.4 GHz Wi-Fi but only provide support for the 5 GHz system due to interference and other issues.
At home I have 2 APs but only turn on 2.4GHz on one because that is the only open channel. A misconfigured router owned my a neighbor interferes with the remaining 2 non-overlapping US channels.

Hey, I’m also at a university! Specifically, the University of Victoria in British Columbia, and previously University of Waterloo. I do all communications and website work, so the IT folks don’t let me touch anything and get suspicious when I ask too many questions.

I’m inclined to think that in many cases, wifi is going to be fine for home automation, but the only way to know for sure is to avoid it.

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I am originally from the Toronto area but am now in Virginia.

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I suspect that a University would be a particularly challenging environment. Instead of a blanket “don’t use 2.4GHz” I’d recommend running a WiFi analyzer (e.g. the Android App WiFi Analyzer) in your actual environment to see if you actually do have potential interference. I suspect that the majority of homes out there have no problems what-so-ever in that band. I personally do not. Until recently I covered my full home plus the garage with a single AP even to the basement adequately well on 2.4 GHz. I’ve recently upgraded to a mesh network and now I even get good coverage on most of the yard.

As with most things in life, YMMV. Better to check and perhaps save some money rather than spending more money on the off chance that you will experience these problems. For many home automation enthusiasts, telling them they have to use zwave is the same as saying home automation is not for you. The cost puts it out of reach.

We actually have Fluke & Cape Sensor test equipment. The worst places for interference are in the residences.

A few hundred students per building, each of whom have between 2-4 devices attached to the wifi? Yep, I hear that.

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You misspelled 2-4 of the cheapest devices money can buy. :wink:

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