For 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 sensor tag separately. Ultra low cost and simplicity are values all their own in terms of applications.
My biggest immediately question though and one I'm a little surprised not see addressed, even at the research stage, is any mention of other animals. There is a bunch there about the ultrasonic frequency being well above the human limit of ~20 kHz. But IIRC for example dogs can hear up to like 45-60 kHz, and cats all the way to 65-85 kHz. I assume lots and lots of other animals also can perceive sounds well beyond human senses. Noise pollution is already a somewhat unrecognized but big problem for all sorts of life around us (not that it's irrelevant to human health either), so if more use of ultrasonics made that worse that's a concern. And as a practical matter the product market is probably going to shrink pretty dramatically if it drives pets mad, a lot of people have pets nowadays they care about a great deal. For that matter even in public environments if it messed with service dogs that might have ADA or equivalent implications.
Still, good reminder of various side channels one doesn't always think about.
> And they don’t travel very far, so only nearby microphones would “hear” the tag. That makes the devices inherently private, Deng said, because other people wouldn’t detect any activity unless they were within a meter or so.
It would seem these things don't really produce loud noises, so probably not adding much to the noise pollution that already exists in our environments. At the same time it seems the statement kind of negates the "point" of this tech, that you don't need an active (energy consuming) device close to the source of the events that you want to detect. So not sure of how to interpret it.
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.
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
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.
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".
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.
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.
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.
It's research, not a product. Even with that, framing it as a smart home sensor in the press release is a stretch.
1) 93.75% success rate in controlled conditions, 92.1% in a somewhat-realistic deployment scenario - too low for reliability. I wouldn't use something like that to trigger smart home automations.
2) Range hardcapped at ~1m due to how ultrasound works, you can't centralize detection. Their answer is to give everyone in the household a wearable receiver, which is eeeeeeeh idk, doesn't look consumer-friendly to me.
3) Paper suggests a mix of durable and consumable parts for the transmitter. Their numbers show that the 3d-printed PLA cantilever needs to be replaced every 900 cycles or so. Should work fine, but...
4) ...every transmitter pair needs to be tuned per-setup, every time. Not a plug&play in the consumer sense.
> 2) Range hardcapped at ~1m due to how ultrasound works, you can't centralize detection. Their answer is to give everyone in the household a wearable receiver, which is eeeeeeeh idk, doesn't look consumer-friendly to me.
Sure yes if you could do this with an always-listening smartphone or smartwatch that would be workable, but even then it constrains it to an occupant-activity detector.
Fixing that would require in the best case prompting an app install when visitors arrive. And still it is deaf to any other changes such as a door closing in the wind.
All possible, but feels several technosocial cycles away. Interesting to think about anyway.
Could be more interesting for hard-to-reach underwater sensors. Water attenuates RF quite severely, but is good at conducting ultrasound. The response would have to be in ultrasound, too, of course.
5) These can be great if you want them to be monitored, but if I'm using my wife's toilet when I'm not supposed to, I'll simply hold the disk when I lift the seat.
From the artwork it looks like they're targeting industrial use. Seems like a low grade replacement for bar/qr code scanning. The "wearable" (more likely integrated into some other thing than worn IMO) receiver seems to point in that direction too.
Author probably has a specific use case in mind. Probably some application where EM emissions are undesirable or power is complicated that has thus far resisted automated industrial data entry. Investigating the use of something like ultrasound would align with constraints like that. Someone (department head? PR department?) said that was too niche and to make up some bullshit with mass market appeal.
My 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.
Interesting idea and reminds me of the German train security system PZB which acts completely electricity-free at the signal - a mechanical switch connects a capacitor to de-tune a magnetic resonance circuit, which is then detected by a passing train's magloop transmitter.
Unfortunately... I see issues:
> Those frequencies are above 20 kilohertz, which is the upper limit of sounds humans can hear.
Yeah. Humans' range ends there, at least in adulthood. But what about pets? Wildlife? Children and toddlers? Or just people that take care of their hearing by not frying their ears with too much exposure to loudness? It's already an issue with "mosquito teenager repellant" devices.
Sure could, but then you would need to do the thing AND think about doing the triggering and then find the trigger button on your watch.
This way you wouldn't have to think about it, because it's automated.
Triggering something manually also doesn't really count as 'automation' I would say.
Obviously not, but there is larger potential than that. A microphone in a watch or phone can pick up the signal and relay the trigger to another server via for example MQTT. Then, you can have homeassistant act upon this signal.
The flow is then
Open door --> Signal triggers --> Signal caught by microphone --> Microphone device relays to server --> Server turns on smart lighting in that room.
There is a lot more that you can do, but this is just an example. The microphone to pick it up is a limitations, but the gain is:
- reduced power usage as the signal generators are not power-operated
- less waste as no empty batteries need to be discarded (if non-rechargeable batteries are used)
- improved security because the signal generators are not connected to the internet, reducing the attack surface.
Right, and they were superseded by battery-powered infrared remotes for good reasons. I would recommend revisiting those reasons before proposing this sort of technology for wireless sensors.
Mostly it was that electronics got cheap enough that you didn't need to keep building the bulky and expensive mechanical version. The first wireless remotes that used batteries were still ultrasonic, they just generated the tone electronically instead of by striking a metal bar. Plus, you could have way more buttons with an electric version; you would need a bar per function for the mechanical way.
Sensors must be using batteries, wear out in a month or so, tied to an oppressive cloud seevice, and regular up-sells of things that would be standard but we stratified types of paying users.
For a dotedu, this is perfectly fine. But this wouldn't pass muster as a real product. You can't do all the HorribleUsesAsAService like almost all IoT hardware is.
I can see some uses, but calling this system batteries free seems a stretch. A sensor is worth nothing if it can't be read, and to read this you need a powered microphone and computing. Some already common magnetic door systems do the same; door plate and magnet movement is enough to create a detectable current, (using no external power), then that signal is read and computed by an electronic/digital system (using power).
Even the layout you describe has massive advantages over the status quo from a placement perspective. Having a reduced footprint device that goes in the actual measurement location that can phone home to a more robust central location like this is not only already very common but also the existing solutions that do it still suffer from the design constraint of requiring a battery which this innovation goes a long way towards
I'm on the side of "clever, fun, but feels useless". But to defend the project, all sensors require a powered central system. It's pretty common for Zigbee to have one repeater per room [1], which is just what is needed for this system.
[1] Because any AC-powered Zigbee device is a repeater, so just a bulb or a plug is enough
My biggest immediately question though and one I'm a little surprised not see addressed, even at the research stage, is any mention of other animals. There is a bunch there about the ultrasonic frequency being well above the human limit of ~20 kHz. But IIRC for example dogs can hear up to like 45-60 kHz, and cats all the way to 65-85 kHz. I assume lots and lots of other animals also can perceive sounds well beyond human senses. Noise pollution is already a somewhat unrecognized but big problem for all sorts of life around us (not that it's irrelevant to human health either), so if more use of ultrasonics made that worse that's a concern. And as a practical matter the product market is probably going to shrink pretty dramatically if it drives pets mad, a lot of people have pets nowadays they care about a great deal. For that matter even in public environments if it messed with service dogs that might have ADA or equivalent implications.
Still, good reminder of various side channels one doesn't always think about.
> And they don’t travel very far, so only nearby microphones would “hear” the tag. That makes the devices inherently private, Deng said, because other people wouldn’t detect any activity unless they were within a meter or so.
It would seem these things don't really produce loud noises, so probably not adding much to the noise pollution that already exists in our environments. At the same time it seems the statement kind of negates the "point" of this tech, that you don't need an active (energy consuming) device close to the source of the events that you want to detect. So not sure of how to interpret it.
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
[0] https://www.amazon.com/dp/B09MHL8QTC
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".
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.
If any of those doors are important for security, then I'd want something an intruder can't easily jam or spoof.
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.
1) 93.75% success rate in controlled conditions, 92.1% in a somewhat-realistic deployment scenario - too low for reliability. I wouldn't use something like that to trigger smart home automations.
2) Range hardcapped at ~1m due to how ultrasound works, you can't centralize detection. Their answer is to give everyone in the household a wearable receiver, which is eeeeeeeh idk, doesn't look consumer-friendly to me.
3) Paper suggests a mix of durable and consumable parts for the transmitter. Their numbers show that the 3d-printed PLA cantilever needs to be replaced every 900 cycles or so. Should work fine, but...
4) ...every transmitter pair needs to be tuned per-setup, every time. Not a plug&play in the consumer sense.
> 2) Range hardcapped at ~1m due to how ultrasound works, you can't centralize detection. Their answer is to give everyone in the household a wearable receiver, which is eeeeeeeh idk, doesn't look consumer-friendly to me.
Sure yes if you could do this with an always-listening smartphone or smartwatch that would be workable, but even then it constrains it to an occupant-activity detector.
Fixing that would require in the best case prompting an app install when visitors arrive. And still it is deaf to any other changes such as a door closing in the wind.
All possible, but feels several technosocial cycles away. Interesting to think about anyway.
Author probably has a specific use case in mind. Probably some application where EM emissions are undesirable or power is complicated that has thus far resisted automated industrial data entry. Investigating the use of something like ultrasound would align with constraints like that. Someone (department head? PR department?) said that was too niche and to make up some bullshit with mass market appeal.
Now companies are desperately trying to figure out how to jack up the price to $10.00 each without us knowing they are ripping us off.
Unfortunately... I see issues:
> Those frequencies are above 20 kilohertz, which is the upper limit of sounds humans can hear.
Yeah. Humans' range ends there, at least in adulthood. But what about pets? Wildlife? Children and toddlers? Or just people that take care of their hearing by not frying their ears with too much exposure to loudness? It's already an issue with "mosquito teenager repellant" devices.
People need smart devices to count their reps !?
Also I guess this might be annoying for pets that can hear well beyond 20 kHz.
If so, will it penetrate through walls?
See http://en.wikipedia.org/wiki/The_Thing_(listening_device)
Could work for drywalls
The flow is then Open door --> Signal triggers --> Signal caught by microphone --> Microphone device relays to server --> Server turns on smart lighting in that room.
There is a lot more that you can do, but this is just an example. The microphone to pick it up is a limitations, but the gain is:
- reduced power usage as the signal generators are not power-operated
- less waste as no empty batteries need to be discarded (if non-rechargeable batteries are used)
- improved security because the signal generators are not connected to the internet, reducing the attack surface.
Sensors must be using batteries, wear out in a month or so, tied to an oppressive cloud seevice, and regular up-sells of things that would be standard but we stratified types of paying users.
For a dotedu, this is perfectly fine. But this wouldn't pass muster as a real product. You can't do all the HorribleUsesAsAService like almost all IoT hardware is.
[1] Because any AC-powered Zigbee device is a repeater, so just a bulb or a plug is enough