This is a very clever idea. However i think almost all smartphone microphone recorders cap out at 44.1khz or 48khz sample rate.
Some have 96khz, but im not sure what is compatible with modern devices. That's going to limit how much frequency spectrum these fingerprints have to work with.
Batteries Not Included, or Required, for These Smart Home Sensors
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Re: Batteries Not Included, or Required, for These Smart Home Sensors
#52What about durability? They are mechanical metal pieces, so would eventually wear down or change tone.
Re: Batteries Not Included, or Required, for These Smart Home Sensors
#53Wonderful. ultrasonic range emission having high S/N is amazing too. My hero usecase for this is to use these for behavioral therapy: Have a ring or a bracelet, thus without reaching for a phone or a notepad, record when a negative thought happens, i.e. a counter, or generate a sequence of ultrasonic sounds to map to specific kinds of thoughts. Have a sensor record and log them. I would then analyze the data across m…
If you're old enough you might remember the Zenith Space Commander (I'm not old enough to have seen one in use).
It was an early TV remote that used spring loaded strikers controlled by buttons on the remote. The strikers hit tuned metal bars that rang out at ultrasonic frequencies the TV detected.
A links below but honestly it's the kind of topic that seems to never be covered well by a single resource. There are YouTube videos showing the inside of the controller and the striker.
[0] https://forums.atari.io/topic/10559-zenith-space-command-vin...
Re: Batteries Not Included, or Required, for These Smart Home Sensors
#54There 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…
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.
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
Re: Batteries Not Included, or Required, for These Smart Home Sensors
#55For a brief, beautiful moment from the headline I thought "oh good, more PoE sensors finally happening!" doho. But no not just about battery but any power at all, and an interesting approach for further research. Of course to actually get data from still requires powered devices but in a lot of cases it'd be much easier to have that be a single or small number of more easily placed central units vs every single senso…
If they are anything like the ultrasonic pest devices people can hear them. I can hear those. I can hear the one a neighbor has near a chicken enclosure every time I walk past on the street.
Re: Batteries Not Included, or Required, for These Smart Home Sensors
#56Earlier quoted context omitted.
Children too. My own hearing extended to about 23 kHz until I was in my early 20s, and I don't think I was exceptional. There was a jewelry store in my town that I couldn't go in to because the "ultrasonic" motion detector was so painfully loud. But I doubt these devices would be a problem for children or pets because the pulse is so short.
Are you sure it wasn’t one of these? https://en.wikipedia.org/wiki/The_Mosquito
Yes. This was more than 50 years ago. The store owner let me examine the device. It was wired into his alarm system. It even had the frequency listed on the label.
Re: Batteries Not Included, or Required, for These Smart Home Sensors
#57For a brief, beautiful moment from the headline I thought "oh good, more PoE sensors finally happening!" doho. But no not just about battery but any power at all, and an interesting approach for further research. Of course to actually get data from still requires powered devices but in a lot of cases it'd be much easier to have that be a single or small number of more easily placed central units vs every single senso…
Children too. My own hearing extended to about 23 kHz until I was in my early 20s, and I don't think I was exceptional. There was a jewelry store in my town that I couldn't go in to because the "ultrasonic" motion detector was so painfully loud. But I doubt these devices would be a problem for children or pets because the pulse is so short.
I mean, TV. Kids were definitely a market for it, throughout its history, but until the flat panel era nobody cared that the flyback transformer in most CRTs made a deafening whine in the 20khz range. I could walk into a house and hear a soundless TV three rooms away, and I know I wasn’t alone in that.
Re: Batteries Not Included, or Required, for These Smart Home Sensors
#58Earlier quoted context omitted.
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
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?
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.
Re: Batteries Not Included, or Required, for These Smart Home Sensors
#59For a brief, beautiful moment from the headline I thought "oh good, more PoE sensors finally happening!" doho. But no not just about battery but any power at all, and an interesting approach for further research. Of course to actually get data from still requires powered devices but in a lot of cases it'd be much easier to have that be a single or small number of more easily placed central units vs every single senso…
Why would this be any different from dropping a coin or other small metal object? If you're worried about ultrasonic noise pollution, nearly every SMPS operates there, and they're constantly running.
Re: Batteries Not Included, or Required, for These Smart Home Sensors
#60My father was an engineer at Zenith when they were developing the Space Command TV remote control. This was a couple years before I was born, so by the time I got interested in hacking, Zenith TVs with this remote were commonplace. When visiting my friends homes I would prank them by jangling my keys and making the TV louder or quieter and randomly change channels. This presents new opportunities.
Wow, I never heard of these. They operated on sound. Here's an article with photos, including some internals and the history of its engineering:
https://www.theverge.com/23810061/zenith-space-command-remot...
I wonder how reliable they were?