71–80 of 100 posts
Im not sure I got it. It generates acoustic signals and a microphone server picks them up. If so, will it penetrate through walls?
Well, idk if these do but you can certainly make passive devices that penetrate walls. See http://en.wikipedia.org/wiki/The_Thing_(listening_device)
Im not sure I got it. It generates acoustic signals and a microphone server picks them up. If so, will it penetrate through walls?
Unlikely because it’s ultrasonic sound, at least if you have brick walls. Could work for drywalls
Just stand on the other side of a drywall and see how well high pitched normally audible sounds get through vs the much lower frequency sounds. It sounds decidedly muffled because all the high has been absorbed.
Earlier quoted context omitted.
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?
Not very reliable. The remote only had four buttons (volume up/down, channel up/down) and various sounds like kitchen appliances, flushing toilets, and jingling keys would be interpreted as remote control actions by the TV. My grandfather had one; he seemed to find it more entertaining to talk to people about it than to actual use it.
So, in the true spirit of the HN dismissive comment, but this time I think it really does have its place. Ultrasonic is DOA, sorry, but that just won't do. It's already a nuisance to have all these switching supplies that mess up your hearing (and some can be surprisingly loud), using it for power delivery is really a non-starter. There was a company that planned on using ultrasonic for power delivery to smart phones…
So, in the true spirit of the HN dismissive comment, but this time I think it really does have its place. Ultrasonic is DOA, sorry, but that just won't do. It's already a nuisance to have all these switching supplies that mess up your hearing (and some can be surprisingly loud), using it for power delivery is really a non-starter. There was a company that planned on using ultrasonic for power delivery to smart phones…
Since it's just a little signal, there's very little power in it, so while your pet might hear it, and maybe it'll cause your noise-canceling headphone to squawk, it's not going to have enough energy to hurt anything.
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 senso…
PoE is lousy for sensors. The switch will cut the power if you draw less than 10mA (480 mW), so regardless of PHY efficiency (which is terrible compared to most RS-485, CAN, or even radio ICs), you are REQUIRED by the spec to generate heat that will mess up your sensor measurements.
Out of genuine curiosity, could you elaborate on this further, or share some sources I could read more on? I knew that was once the case, but my understanding was that significant improvements were made for the Maintain Power Signature (MPS) requirements with dual signature and PD standards in the 802.3bt update. According to [0], in the section on 145.3.9 PD MPS:
>"To further reduce minimum standby power consumption for PoE systems, Type 3 and Type 4 dual-signature PDs can make use of optimized MPS timings when connected to a Type 3 or Type 4 PSE, as shown in Figure 19. PDs assigned to Class 1 through 5 must draw a current of 10 mA for at least 7 ms with no more than 310 ms between pulses. This translates to an average power consumption of 12 mW per pairset, or about 1/10th (12 mW/ 124.6 mW ) of the Type 1 / Type 2 minimum pulse average power consumption."
So my assumption was that the spec had significantly improved on this front starting around 7 years ago? I mean, I'm aware that there can be a very, very great deal of lag time between specs and sufficiently cheap and developed new chipsets taking advantage, but I don't think that's the spec's fault either. In principle if the market was there (and yes, it isn't) the tech could meet it right? My extremely limited experience too is that typical wireless battery powered setups can be sensitive to heat as well in the few applications I've dealt with where it's significant, which makes me wonder if in practice in some cases it might be better to use an IR sensor aimed at a semi-closed or closed but air separated material with known (presumably as close to 1.00 as feasible?) thermal emissivity.
Still, there's lots of sensor use cases where it just doesn't matter, but it'd be nice to be able to hard wire+network on the cheap stuff that's very isolated from wireless signal and physically awkward to get at. I'm fully cognizant though that it's a dream unlikely to be realized, just a personal wish there was more PoE IOT stuff (and while we're at it with magical dream lands that it all had open fully local APIs and everyone worked on first class Home Assistant support and...).
----
0: https://ethernetalliance.org/wp-content/uploads/2019/08/EA_P...
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 senso…
Out of curiosity what do you find missing from the PoE sensor market?
I'd be unironically delighted if you could point me at some site helping me find what I've been missing like a goof, because it feels more like the question is "what isn't missing from the PoE sensor market?" It's pretty niche isn't it, with what little there is available also being at enormously increased prices? Take something as simple as "is there water where it shouldn't be", isn't there basically just the Aquo Proteus XE at $350 and, I think maybe one other I can't remember? Surely there are some "call us for a quote" industrial gear too but it's not exactly the common case vs z-wave/zigbee/wifi. Same with pretty much whatever else one might name. Like, what if you want a semi-permanent motion sensor (not a camera), are there any PoE options at all? I think I remember reading someone working on an mmWave one to get it work with HA but that's it. And yes 100% you can say that it's "overkill" or the like but looking at DigiKey's PoE controller pricing doesn't seem like it inherently has to be a huge premium, just isn't anything mass produced.
I mean, it is certainly very arguable that the entire IOT market is and always has been sort of a total mess more than not, and that PoE switches weren't the $50/8-port affairs you can get now either until pretty recently. I totally understand why it's not a thing, I want to be clear this is more of an idle wistful "that'd be a nicer world" along with all sorts of other areas of tech. And I know there are PoE splitters so sometimes you can get roughly the same effect if something has ethernet+power separately. Wireless is also certainly sometimes simply the most sensible option. Just would be nice to have more options when it counted is all. I've dealt with enough odd spaces where it's a pain to get any signal in and even if it's only once every few years it still sucks to have to have somebody work their way in there to replace a battery and sometimes things randomly fritz out, makes one long for good ol' hard wire with super easy ways to just power cycle the switch and eliminate lots of complicated stacks of networking. Ah well.
So, in the true spirit of the HN dismissive comment, but this time I think it really does have its place. Ultrasonic is DOA, sorry, but that just won't do. It's already a nuisance to have all these switching supplies that mess up your hearing (and some can be surprisingly loud), using it for power delivery is really a non-starter. There was a company that planned on using ultrasonic for power delivery to smart phones…
Did you read the article? It was not about ultrasonic power delivery. I’d describe it more as tuned ultrasonic bells.
Most common one - kiddo smashes it 5 times which kicks it into pairing mode...
Get an SDR, tune into the frequency, and troll the home automation system! Given that it’s not of a high frequency, the attack can be done from a distance with proper antenna, and the frequencies use a hardcoded algorithm. Hell, I wouldn’t be surprised to see flipper zero addon to that (hardware through GPIO and software) for portability.