It is a very cool development but I see couple of issues with it:
1 - It works at about 60GHz. You are not getting a lot of distance or even going through a wall at that frequency and (likely) very low power levels
2 - The devices still need a central "base station". Presumably they rebroadcast to neighbouring nodes; but at lower power levels since they reuse some of the received power for themselves. I doubt you'd get more than 2 - 3 hops out before you don't have much power to begin with.
3 - He cites including these in fridges, coffee makers, light bulbs, etc. None of these are power constrained applications. You can put in $0.45 802.15.4 chip in them TODAY and it comes with a whole microcontroller inside to do what you want to do.
The tech here is no doubt "cool" but I don't see any applicability for IoT. If anything I think it would have some medical uses in pills you can swallow etc. But IoT use is kind of a dud.
Most IoTs have pretty good power source and you can run the w/ existing chipsets.
> Presumably they rebroadcast to neighbouring nodes;
Unless you have a directional antenna, which these don't, you can not possibly scavenge power and simultaneously hope to increase the range by rebroadcasting.
So rebroadcasting is pointless, these simply communicate with the base station.
But what do they do? I mean it's nice to communicate, but you have to have something to say.
The power scavenging circuit looks to not be the same frequency as the communications radio circuit due to antenna size differences. Likely it's harvesting power from 2.4 GHz or similar frequency and then using the higher (24 GHz-ish) band for comms. With a decent meshing protocol this would be quite interesting, although latency with many many short hops will be horrid.
The antenna is way too small for 2.4GHz. It makes sense for higher frequency (60GHz or whatever he said in the video). You can power harvest RF waves straight up but what you absorb gives you very little to rebroadcast again.
There are others doing work on this for sensors you could embed into say a wall to give you the pressure reading of the concrete (a simple piezo say) but those usually modulate an RF wave (similar to NFC) instead of rebroadcasting.
I agree about scavenging. It is inefficient and doesn't make much sense.. They're likely rebroadcasting but at a much much lower power level so the next hop is much closer than the first.
Article says: The antenna had to be small, one-tenth the size of a Wi-Fi antenna, and operate at the incredibly fast rate of 24 billion cycles per second.
Sounds like 24 GHz. But all your critiques are still very valid.
But if you can blanket the world with these kinds of radios and mesh them, think 10s or 100s of trillions of radios, then the range issues are less of a concern but you have a chicken and egg problem which needs many many billions of dollars of investment to kickstart. Great reason for IPv6, though :)
Now Arbabian envisions networks of these radio chips deployed every meter or so throughout a house (they would have to be set close to one another because high-frequency signals don't travel far).
The whole concept is a bit creepy, but that particular sentence stood out. It's not hard to envision these tiny devices all having microphones and cameras... the Internet of Things That Watch You seems not far off.
Microphony in radio circuits is pretty much a given so even if there is no overt microphone every one of these will exhibit a frequency shift when hit by sound waves and that shift is detectable.
Hm. This makes me wonder if you could recover audio from wifi signals.
Maybe you can describe this a bit more. The Great Seal Bug was used for wireless audio recording in the 40's, but this operated by using a microphone/cavity to modulate the load of an antenna; thereby embedding audio in the reflected fields.
Bell did a similar demonstration in the 1890s using a mirror to embed reflections in ambient light and demonstrated wireless audio transmission over 200 meters.
However, I'm not sure why audio would cause a frequency shift in a radio circuit. Perhaps you are meaning the antenna will be perturbed and that could possibly be recovered? I'd be interested to know.
In the times that I was still building radio transmitters (for a very illicit living, selling them to pirate radio stations in Amsterdam) I had to hot-melt each and every long wire and coil in place so that it wouldn't vibrate.
The oscillator circuitry of a transmitter is (even when crystal controlled) sensitive to mechanical perturbation, which typically leads to spurious AM and FM modulation of the outgoing signal. To demonstrate the effect I once held a half our session on air with a guy on the other side of the city by just talking to the circuit board.
In a PLL or crystal controlled transmitter modulating the carrier in such a coarse way is much harder. Typically the modulation is done using a capacitive diode (a varicap) which is a diode whose capacitance changes with the reverse voltage. Because this voltage has to be applied to the diode somehow (in the days before SMD) this meant that that wire was again susceptible to microphony because air pressure on the wire changed it's location relative to the ground plane and that caused a measurable frequency shift. Not nearly as big a shift as in the older stuff but it was definitely a factor.
Wifi radios as much more robust than the stuff that I built. But I suspect that given a sensitive enough detector a residual audio component might be extracted from an otherwise non-audio signal by direct interaction between the sound waves and the transmitter hardware.
In a nutshell, it is very much harder to make something that does not exhibit microphony than to make something that does. You'd have to take that into account from the beginning of the design.
This sounds almost exactly like amorphous computing... but not. Was that bit just left out of the article? Is the intention that these chips will be used one-at-a-time and perform significant computation onboard rather than (as with amorphous computing) having computation be an emergent property of the internetworking of many such chips?
This is going to sound a little harsh, but that's not the intention. I am genuinely curious about emergent phenomenon of computation.
I spent a lot of time messing around with toy evolutionary algorithms. I never really got any satisfaction out of those experiments. eventually I found this [1], and felt sort of foolish.
Has anything really happened with emergent properties in the last 10 years or so?
Actually, most of the uses of the word "emergent" I encounter are exactly as the LW article describes. If you'd replace the word "emergent" with "magic", you'd learn nothing more and nothing less from a sentence. [0]
As for feeling foolish after playing with evolutionary algorithms - I'm not the OP but I can relate somewhat given how I saw people learning evolutionary algorithms and neural networks at my university (and I'm pretty sure it's not a local phenomenon). Evolutionary algorithms are usually explained as inspired by biological evolution, with implicit (and sometimes explicit) note that "evolution made us, therefore evolution is superpowerful, therefore evolutionary algorithms - which are just evolution in code - will be superpowerful too!". Except they're not, and the whole concept is bullshit. It's a belief in Random Number God. Throw enough shit at the wall and something will stick. Evolution is terribly, terribly inefficient, and so are the evolutionary algorithms.
Sure, this inefficiency gives them some interesting properties that may help them avoid particular types of local optimas, etc. But those are mathematical features of an algorithm type, and have nothing to do and share no power with evolution, or magic.
The whole problem stems from people trying to transfer virtues of biology to computing by using a surface metaphor. There's a post on LW that covers it nicely:
"So... why didn't the flapping-wing designs work? Birds flap wings and they fly. The flying machine flaps its wings. Why, oh why, doesn't it fly?"
Or about neural networks,
"A backprop network with sigmoid units... actually doesn't much resemble biology at all. Around as much as a voodoo doll resembles its victim. The surface shape may look vaguely similar in extremely superficial aspects at a first glance. But the interiors and behaviors, and basically the whole thing apart from the surface, are nothing at all alike. All that biological neurons have in common with gradient-optimization ANNs is... the spiderwebby look."
I encounter a lot of similar "medieval thinking" in CS departments. I don't know why. It probably goes in common with the concept of not caring about how the world works.
[0] - it's also a good trick I picked up while hanging on LW; if you don't know why something happens, label it as unknown explicitly. Say "this process is driven by magic", or "caused by Divine Intervention" instead of trying to invent equivalently-informative but sciency-sounding labels like "emergent behaviour" or "spontanous self-organization". This way you'll never forget that your theory still has holes that need to be filled in, and you won't accidentally confuse yourself (or others).
Who is saying that the analogously named models are equivalent the analogs themselves? Analogous terminology and metaphors exist so that people can ease themselves into a deeper understanding of a subject. I agree that some people can incorrectly draw grand conclusions from a simple name, but that doesn't mean the people who use these "things" with these "names" only understand their mechanisms on a superficial level. Seriously, good luck explaining any model without introducing an analog that we, as humans, can relate with.
Sure, I'm not saying analogies are the problem. They're not, we need them, they're important parts of our cognition.
My point was twofold: a/ beware inference from surface analogies, always strive to understand where the border between similar and different properties lie, and b/ it does happen. People do draw conclusions and build their understanding on superficial analogies in a systematic way. That's why I mentioned the anecdote of CS students I know. I've seen it in real life. Also known as cargo-culting, it's unfortunately not a rare phenomenon.
Also, I'm not the CDDDDARP ((cddddar this-comment)-poster), but I hazard a guess that he "felt sort of foolish" because he discovered he accidentally did some inferring from surface analogies and ended up disappointed.
I've just read the paper; it's academically very cool yet practically useless (at least for now).
It uses 24GHz for RX, 60GHz for TX so retransmission is just a fantasy of the "journalist". It requires +45dBm output power (32watts!) at the Basestation to power it at 50cm range, so less practical than regular RFID for now really (and absolutely no chance of ever working as a mesh).
45 dBm is crazy! Do you know the FCC limitations for that frequency? For the ISM bands its +36 dBm EIRP maximum. I'm not familiar with the rules for the higher GHz frequencies.
You'd think it might work better if they had a bit of wire attached as an arial. Then they could use lower frequencies, get more range and so on, perhaps? Having mucked about connecting bits of wire to oscilloscopes it seems most of the signal that you could use to power something is 50/60Hz picked up from the mains. It would still cost cents given a bit of wire is not terribly expensive.
A light bulb I can control is nice, but one that anyone can control doesn't seem very useful. How does one implement security on top, since this is passive?
The article says it has a CPU, therefore in theory it can check digital signatures.
That said, I don't see why would it need to be passive if it's in a light bulb, or any other device that can be actuated. It'll need more energy to do whatever you tell it to, so it can also use that energy to actively power the CPU.
Comparing with existing wireless sensor network "motes", this is much much smaller - but do it's processing/networking capabilities match those of motes?
Its far-field, so it couples completely differently than NFC tags. Also, NFC communicates by reflecting signals, this device communications by active transmission (according to the article, I haven't read their paper yet).
What's new? Its tiny, and I'm very curious how they got that an oscillator to work at extremely low powers. But, it is really just an extension of RFID/NFC/IoT miniaturization work. But then again, just about everything starts out that way.
1 - It works at about 60GHz. You are not getting a lot of distance or even going through a wall at that frequency and (likely) very low power levels
2 - The devices still need a central "base station". Presumably they rebroadcast to neighbouring nodes; but at lower power levels since they reuse some of the received power for themselves. I doubt you'd get more than 2 - 3 hops out before you don't have much power to begin with.
3 - He cites including these in fridges, coffee makers, light bulbs, etc. None of these are power constrained applications. You can put in $0.45 802.15.4 chip in them TODAY and it comes with a whole microcontroller inside to do what you want to do.
The tech here is no doubt "cool" but I don't see any applicability for IoT. If anything I think it would have some medical uses in pills you can swallow etc. But IoT use is kind of a dud.
Most IoTs have pretty good power source and you can run the w/ existing chipsets.