[harg]

There already exists "kinetic" switches for lights etc whose switch contains some passive electronics that when actuated produces enough energy to emit a radio signal that can be read by a relay module. They're pretty handy as you can basically place the switch anywhere you want without the need for the wires to be there. The relay can live in the light fitting or somewhere else convenient.

There's probably no reason why these kinetic switches can't also be used for detecting other events like doors opening/closing etc. I feel like a radio signal is a bit more reliable and easier to detect than high frequency sound.

I also think calling these a "sensor" is a bit of a stretch. They detect events but have no knowledge of the current state of the thing they're sensing. E.g. the can detect a door opening/closing, but have no idea if the door is open or closed at a given time

[buescher]

Piezo harvesting switches and similar (I think there’s a flywheel design out there too) are quite expensive, not terribly reliable or consistent, and require substantial activation force. Conventional switches and batteries that can last for years in remote push buttons and sensors are extremely inexpensive in volume.

[taco_emoji]

The ones I have in my house [0] were not that expensive and have been quite reliable for years now.

[0] https://www.amazon.com/dp/B09MHL8QTC

[ranger_danger]

Do you know of any where the receiver plugs into an existing outlet and has an inline receptacle for the controlling device already wired up?

[taco_emoji]

No, but the one I linked could be wired up that way with a pigtail plug & receptacle, although it'd be pretty big and unwieldy.

[nkohari]

That's not really true. We've used these for years to control our Hue lights, and they're fantastic: https://www.amazon.com/dp/B07MMWH2YB

[IshKebab]

The Quinetic switches I use are extremely reliable and consistent. I've been mentally making a note of when the switch does not trigger the light, and it actually hasn't happened once yet and I've been using them for about 10 years.

You're right that they're expensive and need a decent activation force. They also are quite large and make a quite loud clicking noise which might be annoying for a sensor application.

[fennecfoxy]

Lmao no, my doorbell is one (doesn't have a battery at) and has been going for 7 years strong, as long as I've lived in this place.

Sure you have to press it very slightly harder than a regular switch and the travel is a little more, but not by much.

I think the doorbell cost like £20 in 2020, actually lemme check Amazon...ah in fact it was 15.99£ (now it's £20.99 hmmm) "TECKNET self powered doorbell".

[mechanicalpulse]

> I also think calling these a "sensor" is a bit of a stretch.

Indeed. At best, they're an "emitter", a "proxy", a "relay", a "transformer", or some combination thereof with "sense" or "marshall" that indicates the transformation of input to output a la "sense proxy emitter" or "marshalling sensor".

[IshKebab]

I use these kinetic switches all the time (the Quinetic brand is great and reliable; I've tried a Chinese one once and it died after a few months).

They're good but relatively expensive and relatively large. So I can kind of see why this might make sense. On the other hand having to put ultrasonic microphones all through your house is clearly much worse than a radio receiver, so I'd say these are a bit of a gimmick still.

[Terr_]

> for detecting other events like doors opening/closing etc.

If any of those doors are important for security, then I'd want something an intruder can't easily jam or spoof.

[nh2]

A big benefit of piezo-powered electronics is that they can do all the usual stuff, such storing state, or cryptography to prevent spoofing, which the ultrasonic approach from the article cannot do.