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3-D printed plastic objects that can communicate with WiFi devices (washington.edu)
376 points by soofy 10 months ago | hide | past | web | favorite | 238 comments

> Imagine a bottle of laundry detergent that can sense when you’re running low on soap — and automatically connect to the internet to place an order for more.

Why. Why why why do all IoT-related articles always use awful consumer goods examples like this. Nobody, or next-to-nobody, would want to have that. There are so many good ideas and existing uses of IoT tech outside of the consumer goods sector, and pretty much every application in the consumer goods sector is hot garbage, and consumers know it.

I cringed at that too, but to be honest, this is the least ridiculous implementation of the "automatically order consumables from Amazon" idea - because all the prior versions required you to buy an expensive piece of electronics to mount on something that itself is ~100x cheaper. Here we have a disposable dumb device with no electronics, that could be 3D-printed or mass-produced via the usual techniques.

That said, the usual caveats to this idea apply: it's too easy to have the device order stuff when you don't need it or don't order stuff when you need it, and I definitely don't want to tie myself to a particular retailer.

> because all the prior versions required you to buy an expensive piece of electronics

$4.99 is an 'expensive piece of electronics'?

Anything over a few pennies is too much to put on a bottle of detergent in the factory.

And putting it on at home is foolish - more work than just reordering detergent myself when it runs out.

The previous posts are presumably referring to the Amazon Dash Button: https://www.amazon.com/Dash-Buttons/b?ie=UTF8&node=106678980...

I use a Dash button in my bathroom to automatically order toilet paper.

It's great because I never remember to do that before its "too late", and its still MY CHOICE to press the button. Nobody wants individual toilet paper packages stuck with their own tracking devices, at least not now.

It's weird that articles like to push that idea, rather than more simple examples people might use.

People used to leave their empty milk bottles for the milkman to pick up. Could do the same with detergent bottlecaps.

Now THERE's an idea! Save a trivial part of the packaging of whatever you need to reorder, put in in a bowl by the garage door. When you go out, grab a handful. No list, no remembering, and super easy to do!

$4.99 says it is subsidized.

You are describing the end-user price of a device that includes batteries, a circuit board, a WiFi transciever, a switch, and an enclosure. If the BOM and assembly costs can be brought down to $4.99, that's a miraculous feat of engineering and modern civilization's economies of scale; if it can end up on your doorstop for that price it must be subsidized.

How else could that device cost less than the gallon of industrial chemistry that you order with it?

Yeah, I find it hard to believe this device could be sold for $4.99 at a profit, if you count up BOM, assembly and logistics related to sending it. But given that some posters mention Amazon actually gives you $4.99 back for the first purchase, they must not be caring.

Anyway, here's a teardown I found:


Now a surprising thing that I didn't know before - this thing has a microphone on board. Yes. Yet another Internet-connected microphone. Apparently used only to configure the button via ultrasound, but I wonder how hard would be to repurpose it...

Check this out: https://www.aliexpress.com/item/ESP8266-ESP-12-ESP-12F-CH340...

$2.72 for a single programmable WiFi device, delivered for free. All you need after that is a cheap battery, button, and enclosure. The existence of the ESP8266 is changing the way I think about electronics.

> delivered for free

which is subsidized by the USPS and Chinese government using mail reciprocity agreements to ship for pennies.


Why not a bluetooth SoC like nrf52832 or DA18586 and a esp32 for wifi-bluetooth bridge? The price is the same.

This way you will have months or even years in autonomy instead of weeks.

I don't know about that - I can pick up a ESP8266 dev board for under $5 individually on mouser - I feel like I should be able to get that cost down significantly if I am building millions. I am not an expert in manufacturing at all but it seems like I should be able get a small enclosure and battery for under $1.50 in high enough quantities.

It might be worth it as a funny gadget once. But not when you'd like to have 20+ of those in your house. Or one for every product that you order regularly.

Don't forget that you get that $4.99 credited back to your account on first use.

It is if you take into account the fact that the people buying one for a product are most likely going to buy more for other products too.

The very few people I know with them have 5 or more. That adds up. Especially considering you could just modify one to handle any number of products.

This is still ridiculous. It doesn't actually use WiFi communication and it cannot work reliably across variable environmental conditions.

> It doesn't actually use WiFi communication

Actually it does. It manipulates the WiFi signal.

> it cannot work reliably across variable environmental conditions

Nope nor can my tablet, notebook or streaming stick but 99% of the time. It does work almost all the time though. I really think this is possibly the best scientific measurement tool idea I have seen in a while. Minimal of parts should keep this working for years and no electronics sounds like there will be many different applications.

>> It doesn't actually use WiFi communication

> Actually it does. It manipulates the WiFi signal.

Actually, it doesn't. It scatters back some radio frequencies, including 2.4GHz, which happens to be used by Wi-Fi... and Bluetooth, and Zigbee, and other stuff that people might have in their homes. You still need at least a dedicated radio driver, which has absolutely nothing to do with Wi-Fi protocol, to actually read the data those devices send.

Your comment is a good example of exactly why the way this article (and the original paper) uses the word "Wi-Fi" and "connection" is a big problem. See also: https://news.ycombinator.com/item?id=15861392.

> Your comment is a good example of exactly why the way this article (and the original paper) uses the word "Wi-Fi" and "connection" is a big problem.

The main point of the article was : "University of Washington researchers are the first to make this a reality by 3-D printing plastic objects and sensors that can collect useful data and communicate with other WiFi-connected devices entirely on their own."

Um I don't understand if you look at the flow chart this paper is narrowly speaking about wifi that it is

Wifi TX --> 3D Printed Object --> Wifi RX

I am talking about how this is 100% wifi communication and sure the Wifi RX is where the success of this relays. Sure it will work with other protocols but this is about them specifically using it as a way for Wifi RX

> > Actually it does. It manipulates the WiFi signal.

> Actually, it doesn't.

"backscatter" the Wifi signal isn't manipulation?

If you follow the "Backscatter" link in the article they actually state the following:

"This new “interscatter communication” works by converting Bluetooth signals into Wi-Fi transmissions over the air." http://www.washington.edu/news/2016/08/17/interscatter-commu...

So they can convert signals from bluetooth to Wifi isn't manipulation?

Your statement of

> It scatters back some radio frequencies, including 2.4GHz, which happens to be used by Wi-Fi...

Seems off to their own "backscatter" definition. This is not simple reflections of radio signals these technically are new signals physically manipulated by the non-electronic devices.

> Wifi TX --> 3D Printed Object --> Wifi RX

No, it's:

Wifi TX --> 3D Printed Object --> general 2.4GHz RX through a specialized device or driver for an existing 2.4GHz device

They're not magically encoding new Wi-Fi packets; they're changing the amplitude of Wi-Fi packets - and everything else that's on 2.4GHz - seen by the receiver. Contrast with the interscatter you mention, which uses an electronic device to encode new Wi-Fi packets.

Interscatter is not what's happening here.

No I quoting a fact not an opinion. Please read my comment and sources before claiming I am factually wrong.

"In this backscatter system, an antenna embedded in a 3-D printed object (middle) reflects radio signals emitted by a WiFi router (left) to encode information that is “read” by the WiFi receiver in a phone, computer or other device (right).University of Washington"

Screenshot: https://i.imgur.com/rzX4RXX.png

> They're not magically encoding new Wi-Fi packets

Yes, these are NEW signals powered by the radio signals that specifically in this article is wifi since it is so widely used.

"The chip uses a technique called long-range backscatter to communicate with other devices. Instead of creating signals from scratch, it is able to selectively reflect radio waves that are already passing through space to create a new signal." https://www.technologyreview.com/the-download/608869/a-new-m...

Just because they are using residual radio signals (They could use TV, Wifi or FM signals) doesn't mean the new singals aren't new. They are just using the energy in the signal itself doesn't make them magic. Instead of using electricity from a battery or a cord they are using the power of the radio wave. They can even power themselves off of the Gollakota’s radio frequency power scavenging technology. You could light up a led without any on board electricity and communicate between two devices https://www.youtube.com/watch?v=gX9cbxLSOkE

Here is a speech about HitchHike: Practical Backscatter Using Commodity WiFi at (SenSys 2016) https://youtu.be/4tmatoD0I1o?t=3m48s

You quote yourself "reflects radio signals". If you look at the paper, they are reading signal strengths with which they receive the packets the first station sends and are using the change between different packets to read the data. From the paper:

> At a high level, a Wi-Fi transmitter sends a sequence of Wi-Fi packets and the Wi-Fi receiver uses the changes to the amplitude of the Wi-Fi packets, caused due to the backscatter operation, to extract the backscatter information

> So we decode the backscatter information from the amplitude variations in the received Wi-Fi signal across packets.

Your other links again are about totally different projects, doing different things (they involve chips for instance, not just 3D printed components. "Of course" chips can actually send/manipulate data at the speed necessary to generate packets, nobody is arguing against that)

Okay never mind don't read my sources. This 3D printed Plastic is using backscatter techniques. I'll just quote the article and realize your not understanding where this invention is coming from and why this is new worthy and not just some wifi reflections.

"To 3-D print objects that can communicate with commercial WiFi receivers, the team employed backscatter techniques that allow devices to exchange information. In this case, the team replaced some functions normally performed by electrical components with mechanical motion activated by springs, gears, switches and other parts that can be 3-D printed — borrowing from principles that allow battery-free watches to keep time."


"Information — in the form of 1s and 0s — is encoded by the presence or absence of the tooth on a gear. Energy from a coiled spring drives the gear system, and the width and pattern of gear teeth control how long the backscatter switch makes contact with the antenna, creating patterns of reflected signals that can be decoded by a WiFi receiver."

I read your sources. Nothing you quote here contradicts what I said if you read it in the context of the entire paper. E.g. " creating patterns of reflected signals that can be decoded by a WiFi receiver." isn't technically wrong, but very misleading, since what they analyse for data is the signal strength the receiver sees across the packets, not the content of the packets. That's why we are arguing that they present it terribly.

A Wifi packet is a few milliseconds long at best, it should be obvious why a 3D printed mechanical thing can not be fast enough to change bits in there to actually generate a new packet.

Please note that I'm not claiming that it's not using backscatter techniques, that it isn't novel or that it isn't interesting. Backscatter is a generic enough term to cover all these things, despite them being quite different.

I'm claiming that it does not generate Wifi packets. It merely changes their physical characteristics in a way that can be detected, without changing anything about the packet contents.

> I'm claiming that it does not generate Wifi packets.

How does the Wifi transmit how much laundry soap or any measurement if it wasn't new packets???? Maybe if you can just look at this for 2 minutes you'll understand how this is new packets? https://youtu.be/4tmatoD0I1o?t=14m5s

It has to be received and transmit data. Your assuming a reflection is what's happening. Than a mirror could also do the same thing?

This is your laptop or Smartphone able to receive a signal from a 3D device with no new hardware using only the power of a Wifi transition signal that a Wifi receive will read.

That link has nothing to do with what we're discussing here. The video is about active electronics. The article being discussed here is about variable reflection of RF signals based on pure mechanics and zero electronics.

The project discussed in this article is exactly like a mirror, but for RF. If you'd attach a mirror to a spring and had it rotated back and forth with a cog-like thing, you'd have built the exact same thing they're presenting here, except for light. You wouldn't want to call it "Li-Fi communication" just because the mirror can reflect the same frequencies Li-Fi devices use, though. Which is why calling this project a "Wi-Fi device" is wrong.

As a former research librarian I have to say please check why in the world you are going down this path. It is 100% a Wifi device that is sending new packets. There is zero chances that what you are assuming to be true would work.

They are called in the published paper "printed Wifi devices, Wi-Fi input widgets, 3D Printed Wi-Fi Smart Objects." If your smarter and see how stupid or misleading these Phds are and MIT for publishing these finding then do it. Otherwise you are basing your whole argument on incorrect presuppositions and you didn't do any due diligence to see your missing knowledge how these actually work. How in the world would you send measurements to a Wifi receiver in your laptop? You would send a measurement of test tubes to a laptop without any electronics and no dc power.

Read how this is done for measuring wind speed:

"We 3D print a cup anemometer as shown in Fig. 2 to measure wind speeds. The entire setup is sufficiently light that even wind speeds as low as 2.3 m/s will cause it to spin. The hub of the anemometer is attached to backscatter gear that encodes an alternating sequence of zero.

I understand your missing the similarities in the projects but they are all related by the same principles. The 3D printed Wifi devices (plastic adn metal, are doing what is normally requiring circuitry.

Stop with the trolling.

I promise you I am not trolling read page 242:12 on WIFI INPUT WIDGETS. It explicitly states it sends packets.


Achieving data communication using push buttons requires us to address two unique challenges: 1) we need a mechanism to identify the beginning of a packet, and 2) since users can push buttons at different speeds, we need an algorithm for symbol synchronization.

On page 242:5, it explicitly says that it doesn't send new packets.

> In our case, the backscatter signal is a narrowband transmission embedded on top of the ambient Wi-Fi signals, since the printed Wi-Fi objects send data at a low data rate.

Even your quoted text doesn't say that it sends packets IMO.

Please explain how it works in as simple terms as you can?

My explanation:

The 3D printed Wifi device uses plastic and metal to connect to any Wifi receiver (normal laptop or smartphone) using any commercially available Wifi transmitter. 3D device uses it's antenna to send new data. The data is sent uses reflection and absorption of the Wifi signal to create new data of 1s and 0s though at a slower rate of speed. This is all done without the need for batteries or other electronics. There is no special hardware or software besides the 3D device to connect and send data. The device can toggle an electronic switch to either absorb or reflect an ambient signal to convey a sequence of 0 and 1 bits using reflective and non-reflective states. This is accomplished by leverages present Wifi backscatter technology but for the first time instead of using electronic components these 3D devices use non-electronic and printable analogues.

> "embedded on top of the ambient Wi-Fi signals,"

That is how backscatter works and how they connect to wifi and send specific 1s and 0s. It absorbs and reflex a wifi signal out of those absorption and reflections.

It can't work without some signal to carry on top of it and could work with a single 2.4 sine wave. But backscatter absolutely sends measurements to a normal Wifi rx aka a phone or laptop through the Wifi transmitter.

While I'd agree that they "manipulate" the Wifi signal, I also have a hard time calling something that doesn't generate Wifi frames or packets "Wi-Fi communication". It merely changes the signal strength of existing packages (or packages specifically generated to fill air-time, which seems like another large downside of this). It does not generate new frames or insert data into them.

But it is a new signal originating from the 3D object. They even convert Bluetooth to Wifi signals with this technique. Read about comment of mine for source.

The technique you mention is realized through an FPGA chip. It is not used in the 3D-printed backscatter devices this article is about.

Not this is through the Printed 3D Device

From the paper

"We 3D print a cup anemometer as shown in Fig. 2 to measure wind speeds. The entire setup is sufficiently light that even wind speeds as low as 2.3 m/s will cause it to spin. The hub of the anemometer is attached to backscatter gear that encodes an alternating sequence of zero one bits. When the hub spins, the backscatter gear pushes against the spring switch. The switch makes contact with the antenna and generates the backscatter signal. Wind speed can be inferred from the rate at which bit transitions occur."

That's a totally different project than the one this submission is about, using totally different technology. The 3d-printing one is modulating things in the range of few Hz, you're not making packets with that.

Backscatter is the same technology in both projects. Yes, scientifically they are new packets.

See https://youtu.be/4tmatoD0I1o?t=3m48s

They could do it with a radio signal of a clean sine wave and through the 3D object they could convert the sine wave into wifi. Just like they could take a bluetooth wave and make a wifi signal. The big advantage to this is they can just take a Wifi and use it to do the same thing. No need for new hardware.

They are similar in a very high-level view, but that's exactly what's causing the confusion here. Yes, the video you link is about a project that is actually generating Wifi signal. The article discussed here is not, and it's IMHO irresponsible by (what I assume was) the PR department of the university to present them as doing the same. Take a few minutes and compare the papers (printed Wifi http://printedwifi.cs.washington.edu/printedwifi.pdf and Hitchhike https://web.stanford.edu/~pyzhang/papers/sensys16_back_comm.... or interscatter http://interscatter.cs.washington.edu/files/interscatter.pdf), the principles used are very different. The 3D printed objects only switch an antenna which attentuates (=modulates the signal strength of) Wifi signals with a few Hz frequency at max, HitchHike and interscatter involving electronics completely transform the signal at HF level, retransmitting full packets at a different frequency.

They are both "backscatter" in that they change an existing signal and thus require less energy than if they generated it themselves, but that's about it when it comes to similarities.

They both must have single side modulation for anything to work. If not than Wifi and FM and AM would never work since everything would confuse the receiver.

I thought maybe I am missing something, but I see that the objects are encoded with bit and transmits.

Printed Wifi Paper

"PRINTED MAGLINK At a high level, by varying the magnetic properties of the material used within a single print job, we can embed multiple sequences of bits across the object. We consider the 3D printed object that modulates the magnetic field as the transmitter and the smartphone as the receiver.

Maybe it is the word modulates that is the issue?

Modulate Definition - In electronics and telecommunications, modulation is the process of varying one or more properties of a periodic waveform, called the carrier signal, with a modulating signal that typically contains information to be transmitted. Most radio systems in the 20th century used frequency modulation (FM) or amplitude modulation (AM) to make the carrier carry the radio broadcast. https://en.wikipedia.org/wiki/Modulation

> I thought maybe I am missing something, but I see that the objects are encoded with bit and transmits.

I think you're confusing three or four different projects at this point, whose only common property is that they operate on the energy of an incoming 2.4GHz signal (the "backscatter" thing).

The project that is the topic of discussion in this whole HN thread is the one that uses a 3D-printed plastic mechanism that changes the way an antenna (incidentally, 3D-printed too, out of a filament that mixes copper and plastic) reflects an incoming signal. There is a binary pattern, but it's encoded in the cog-like thing in the mechanism.

It's pretty much like sending light signals with a mirror, except it's reflecting radio waves. The way they use technical terms in this article (and the original paper) is problematic, and I believe your confusion in this subthread is a perfect example of why the abuse of "Wi-Fi" references is a problem.

No read the paper once. I did and I learned a ton and than I commented. When people don't read the material and assumptions are made is how you get into these arguments.

> There are so many good ideas and existing uses of IoT tech

Could you give some examples? I've yet to hear a single IoT thing I'd be willing to pay money for.

Just yesterday, it occurred to me that an IoT thermostat would be nice (if and only if it doesn't mean that a server failure results in me freezing). Right now, I have the choice of heating the house all day (thus wasting heat = energy = money while I'm not home), or coming back to a cold house, turning up the thermostat and then having to wait 1-2 hours until the room is pleasantly warm. (My apartment is understaffed in the heater department and I cannot change that easily since I'm renting.)

Those have existed for years, apartment buildings are just usually cheap and lazy and don't install them.

I've got a Honeywell model [1] I can set from anywhere via an app. It also has scheduling it falls back to if I haven't overridden it via the app or faceplate. My winter weekday schedule: 66 at 6am, 62 at 9am, 65 at 4pm, 62 at 10pm.

1) https://www.amazon.com/Honeywell-Programmable-Thermostat-RTH...

ive got the same one. works great.

It's quite easy and cheap to make a wifi-connected thermostat yourself. I did it, it's great.

I made a web interface so that I can control it with my phone when I'm not at home.

It is based off an ESP8266 placed in the boiler which controls a relay to tell the boiler whether to heat or not, and an ESP8266 in my office that has a temperature probe and a rudimentary user interface, and runs a web server to allow remote temperature inputs, and controls the ESP8266-relay over WiFi.

The 3d-printed enclosure is rather coarse, but does the job: https://img.jes.xxx/1585

EDIT: Failure of the system could result in you freezing, but that's true of anything that controls your heating, and at least this is a device you understand are in control of, and it doesn't rely on anything outside your house. If it fails and you're freezing, just short the terminals of the relay while you debug it.

In cold climates, the problem with failed thermostats isn't frozen people, it's frozen pipes, which can happen when the people aren't home.

An easy way to insure against such failure is to put your homemade thermostat in parallel with an old fashioned thermostat which is set to a constant low temperature.

A seemingly common safety is to wire the custom thermostat in parallel with a simple commercial one so that the commercial one kicks in if the temperature gets too low.

If you are in Europe, you can also buy the ESP8266 from Olimex with relay, box and eventual lipo plug. You then just have to flash your code on it. Only downside is they are not properly shielded electromagnetically so they can only be sold as Kit for experienced users (as certification costs would dominate the price). Also, if your house happens to burn, you can be pretty sure the insurance companies will pin it on your uncertified DIY appliances.

> Also, if your house happens to burn, you can be pretty sure the insurance companies will pin it on your uncertified DIY appliances.

This is one thing that's constantly on my mind when toying with long-lived electronics projects. Do we know of an actual precedent here?

I don't know of actual precedent, but there are numerous examples of lipo house fires (which aren't fully covered). And semi related personal one-datapoint anecdote I've experienced water damage and robberies in the past and they were a lot more prompt to try to find loopholes to not have to pay. I can't afford to set a precedent, so I stick to fused low voltage off the shelf products.

Use an off the shelf wireless plug in switch and a Telldus transmitter then you don't do any high voltage or high current wiring at least if you are controlling a standalone heater.

I want a DIY Smart Vent to go with 3D Printer Thermostats in each room.


Thermostats with scheduling capabilities have existed for a long time and they don't need the internet to do it. Unless you're referring to when you're out of the house when you would normally be home?

Are there not thermostats on the market that let you program schedules? If you do want something a bit more connected, thermostats in the Lyric line from Honeywell[1] can give you things like scheduling and geofencing (e.g. "oh, you're on the way home, let me start cooling...") Of course, a geofence isn't going to function if you're offline, but the thing should definitely remember a time schedule to use as a backup when connectivity is lost.

[1] I work for Honeywell

They exist, I have one and find it useless:

When I go on vacation for a week there is no way to say "go to max energy savings while saving my pipes mode until just before I get back." I can reprogram the entire week, but then I lose what is the correct programming for normal until I reprogram it. Worse my house is uncomfortable when I get back - usually when I'm tired and want to jump into bed asap (if I know I'll get home about noon I'll look for a tourist thing to kill some time long before I get home).

I don't always have the same schedule. When I'm home sick I don't want to reprogram it. Some weekends I'm at home all day, some I'm out all day - which program is right? IoT thermostats also through privacy and reliability concerns in. The old fashioned mercury thermostats from the 1950s still work as good as new. While your IoT thermostat work next year - some do not.

All the above is made even harder because my house is headed by an air source heat pump: if I'm returning at 9pm it might or might not be better to start heating my house at 11am when the day is warmest. The algorithm depends on the weather which is best predicted the day of.

My Honeywell t-stat has a schedule and a hold function which can be either timed or permanent. If you want to lock a temperature, you can tap the hold button a couple times to set it to "permanent hold" and set the temperature to whatever you want.

Timed thermostats would probably get you 90% of the way there.

Programmable thermostats have existed for a long time and it's easy to find internet enabled ones these days.

The problem is that you're renting so you can't do any cool home automation stuff.

thermostats are trivial to change if you have any electronics or handy skills, just don't put new holes in the wall that aren't hidden by the mount plate if you're renting. It's basically like replacing the shower head while renting.

That already exists, here is a widely recommended version.


I am honestly not sure why this is getting down voted. The nest thermostat does continue to work as intended when offline. Of course you won't be able to use the app while you are away to control it.

You get timer-based units that reduce the temperature at night (optionally also when you are at work). They cover a good chunk of the usecase and will give good amounts of savings. No Internet, mobile app or machine learning needed.

No, but here's a bad idea I tried.

My HP printer can reorder ink when it runs out.

Sadly, that all got balled up almost immediately. The offer came with a mailer for exhausted cartridges. I put them in the mailer, put the mailer in the box (rural route). My spouse mistook it for incoming mail, ripped it open, said "Why is HP sending us empty printer cartridges?"

Fortunately HP had a button to click on the web site to get another mailer mailed to me. I clicked, got the mailer (which was entirely different from the one that came with the offer) and sent the cartridges off.

That was weeks ago. No new ink. My credit card continues to be debited monthly, but the printer is defunct and now what?

These things are so, so prone to getting in a wad and leaving you frustrated. More work than actually buying new cartridges as needed.

Essentially you need one spare for this system to work. Which is great for them because it front loads cartridge sales.

I said "no more" to printer cartridges over a decade ago. I rarely print things, and when I do, it's usually black ink on white paper.

I was always running out of black ink, or, because of infrequent usage, my inkjet cartridge/head would be clogged. I was so sick of it. I just wanted to hit "print", and have the printer spit out the page - like I could at my employer.

What did my employer use?

A laser printer. So I started looking into it. The last time I had, such printers were still expensive, but they had come down in price. But even better, because of this, businesses and others were getting rid of their "old and slow" b/w laser printers and upgrading to faster color ones. I eventually found my first laser printer at a computer surplus outlet.

It was an HP Laserjet 6M - I paid $100.00 for it, but it didn't have a cartridge. It was a gamble, but I asked the place if I could return it if it didn't work, they said "sure".

I went to a local ink cartridge and printer ribbon store I knew about (they were an old-time fixture here, they even sold typewriter ribbons! Sadly, they no longer exist), and told them my dilemma - I needed a cartridge to test with, I didn't know if the printer worked. They gave me a mostly used cartridge from their refill pile, and told me to bring it back and they'd refill it for me if it worked! Grateful, I took it home and plugged it in.

It worked perfectly! I ran the self-test, and the printer only had about a 25000 page count - a baby! These old LaserJets are tanks, and that was a very low page count. I took the cartridge back, and got it refilled. Total score!

Some time went by, eventually I upgraded the memory to the max (8 MB using common SIMMs) and got the PostScript board for it (so now it is technically a 6MP). It still chugs away, prints when I want it to, I just have to keep feeding it paper - which is rare, because I don't print much.

I'm also only on my third cartridge; I can get them fairly cheap from multiple places, and still a lot of business use these tanks because they are so damn reliable. It isn't a fast printer, but I don't need this thing to spit out a book a minute, just a page here and there; I can wait.

One of the best computing purchases I ever made.

Years later I found a 5P at a Goodwill with the cartridge. I fired it up in the store, and it too had a very low page count (around 15K). Bought it for $25.00 and stuck it in my shop - I also bought the postscript board for it as well. My original intention was to use it for printing toner transfer PCB art, but costs for PCB fabbing have dropped low enough that it isn't really worth it. So I just keep it if and when my 6MP dies...

I figure I'll pass away long before these workhorses do.

I rescued a LaserJet 4L in the late 90s that was being thrown out for constantly grabbing multiple sheets and jamming. Gave it to my parents - with a thorough cleaning, it didn't grab or jam any more and gave them 10+ years of good service (might still be going even now, I dunno.)

IoT furniture + tags. Put stuff [with tags] into cupboards and whatever, and when you're looking for something you can locate it [via that damn' app], so cheap & green tags would be nice.

Similarly tagging stuff that you bring yourself to any group event (let's say you are an event organizer and you hand out things and you want to easily account for them).

Sole pressure monitors in shoes would be great to detect problems with stance/gait/load, etc.

I've thought of doing this for all the stuff kids need for school, plus our own keys etc.

Rather than "IoT" tags, I'm of the opinion that we should use dirt-cheap (a few ¢ each, rather than $10+ for a full "IoT tag") RFID tags, and have a reader that can be accessed by a phone over Bluetooth (or have a few permanently installed around the house). Just need to drive the cost of the readers down.

Ah, yes, there's no "IoT" tech, it's just BLE (Bluetooth low energy) beacons and RFID tags, and whatever is out there.

I'm a bit astonished how it still costs 15 EUR for a BLE thingie. :o

I find wifi lightbulbs very useful.

Unfortunately a lot of people don't realise how useful until they actually try them. For example getting home and having the lights turn on that you'll need automatically.

Before we had to navigate our way to the other side of a open plan room in the dark to find a light switch, now the motion sensor triggers the Hue bulb.

Plus we have a dimmer without needing an electrician to install one, and can set other colors of light for the mood or to improve the atmosphere of a movie.

You can get started with Philip's Hue for $50 (on Black Friday) and at that price point it is well worth it for a lot of benefits/circumstances.

> For example getting home and having the lights turn on that you'll need automatically.

This would be easier to determine if I lived alone. When someone comes in, someone else could be sleeping, watching something in the dark, etc. There's a decision tree for which lights to turn on and how bright.

What I would expect the lights to do is more complex than I would want to spend the time perfecting. I like tinkering, but not with things that I actually rely on. That's why I haven't tried it. Well, that, and because I'm not willing to give an appliance an internet uplink.

If you're more technically inclined you can get started for much less.

You can get an ESP8266 individually for $5, and its only a few more dollars for a relay or a couple of MOSFETS depending on what you want to control. You can use the Homie for ESP8266 framework to take care of the boilerplate, and build functional device that communicates over MQTT in less than an hour.

Most open source home automation software supports MQTT and you can use habridge to emulate Phillips Hue devices if you want to integrate it with an Echo or other commercial device.

Before we had to navigate our way to the other side of a open plan room in the dark to find a light switch

That's not a matter of trying them, it's whether you live in a house with a crappy installation. A switch on every entrance is a basic requirement. I agree that if you're renting, fixing those problems yourself for $50 can be useful, though.

I got my house filled with motion activated lights at less than $10/piece

Perhaps but I bet they aren't as flexible. You're paying for that flexibility and functionality (multi-color, dimmable, etc).

For one example imagine if you're away on holiday but want to give the impression somebody is home, you'll need to invest in a timer, with Hue you've already got that.


You mean, pay $5? Plus it works for other stuff besides lights (we turned on a radio too).

In the winter season, the hue sunrise mode is a great help to waking up well. (when it's still dark outside)

I’ve found zwave/wifi switches to be much cheaper to outfit a whole house with.

Couple of monitoring ideas I have that I've yet to see implemented: "did I lock the doors" and "did I leave the gas cooker on".

My ideal version of this kind of monitoring is an interface that lets me teach an app what doing things in the house sounds like - new activity name: shut door and lock > record a few runthroughs; then log when it happens, offer push notifications, etc. I have an induction range that helpfully makes lots of beeping noises while many gas ones do not (but also turns itself off), so that would also be possible.

IoT seems to be overengineering for these use cases. Doors that automatically lock when closed, gas that automatically turns off after a certain time (mechanical timer), solves the problem without the need for adding always-on electronics. These features are standard in a large number of apartments in Korea.

Smart locks are done. First result for smart locks is a PC Mag end of year review.

See here: https://www.pcmag.com/article/344336/the-best-smart-locks

GP was talking about monitoring. Answering the question, "did I lock the door", doesn't require an Internet-connected lock with electronics and actuators. A simple backscatter status reporter using the tech presented in this article would be more than enough. Ditto for the gas cooker.


And speaking of smart locks - in the current IoT - that is, cloud-connected - version, they are just idiotic. Such things shouldn't be vendor-locked and their core functionality should be available over LAN. Even that PCMag article doesn't seem to recognize it, as they don't have an "works without Internet" row in their table.

I'm definitely not an advocate. Anytime someone asks me about smart devices/IoT, my recommendations always defaults to "generic" devices. I think we give up too much of our privacy and control to vendors - especially when there are solutions that don't require cloud servers.

Smart locks and some HASS script can do the lock the door thing.

Although you might just have it monitor your housemates smartphone location and lock your doors if all phones have left the house. If you don't want it to lock, it will just push message you the lock state.

Would it be possible to use passive RFID with a sensor to measure if the door is unlocked or the stove is on?

From my personal experience: crop and greenhouse monitoring. There is an interest in having more data, from off-grid sensors across a wider area.

If you shop at stores that have a modern cash register, buy gas at most gas stations, drive through most traffic lights, etc. you are using the IoT whether you know it or not.

Those were around before IoT was even a word, POS registers and gas stations haven’t changed much since the 90s. Traffic lights ditto, many haven’t been upgraded since the 80s.

If that is what you mean by IoT as just a rebranding of things that have been around for a long time?

As someone who makes industrial electronics, it's frustrating when people redefine the term IoT. It originally meant anything on the internet that isn't a general purpose computer (or a phone), but now some people define it to refer only to a subset of consumer products.

That's given rise to the term IIoT (industrial IoT), but it's still troublesome since some discussions of IoT refer to both kinds and some don't, and because the exact same piece of hardware can be IoT or not IoT depending on whether it is installed in a home or a business.

Surely discussions of IoT security should refer to both industrial and consumer products!

IoT never had that meaning. It stems from CMU smart devices work (1982) and ubiquitous computing (1991). Gas station and retail POSs as well as smart traffic lights predate that and aren’t related. Maybe some people have decided to take IoT literally and redefine it to include existing technologies, but that definitely wasn’t the original intention of the word.

> Gas station and retail POSs as well as smart traffic lights predate that and aren’t related.

> Maybe some people have decided to take IoT literally and redefine it to include existing technologies

I'm pretty sure it's normal to take new descriptive terms and group preexisting things into them where applicable. For example, just because the terms "car" and "motor car" came into use circa 1895 doesn't mean that nothing prior to that date can be considered a car.

Whether the definition actually works for the devices mentioned is still a valid question though.

> that definitely wasn’t the original intention of the word.

That's an odd thing to argue. We aren't talking about people who compute things when we talk about computers, are we? The original meanings of words are fairly inconsequential if over time the accepted meaning is something else.

> Nobody, or next-to-nobody, would want to have that.

I wouldn't say that. I think that everyone would want it if it didn't add more work, cost or mental overhead than it would remove. And to do that it would have to be ridiculously reliable and simple and be integrated into the products rather than work as an add-on. That won't happen for many years for many of those products.

reliability was my first thought with these. It is a very clever technique. However, the mechanical spring properties would seem to be very important. I'm sure they have designed the spring to be in an approximately linear stress/strain region, but material creep seems like it would be more prevalent than traditional engineering materials. Perhaps if the lifespan of these objects is relatively short, then they would satisfy the reliability goal.

> Nobody, or next-to-nobody, would want to have that.

Hi, I'm your nobody. I'm constantly running out of soap and shampoo and other trivial home goods because I always forget that I need them until the moment I get back home. Why wouldn't I want a feature like that?

Here's a simple solution: next time you buy soap, shampoo, laundry detergent, etc, buy two of them and put the one you're not using in a closet.

Or buy double the amount you bought last. You'll eventually stop running out of detergent.

When the first one runs out, replace it with the second, and go buy another. You have a buffer to remember to buy the item for your backup inventory.

And the remembering is done by means of a list on your phone. When you run out, add it to the list. When you're at the store, check the list.

Not techy enough for ya? Think of it as preserving state and passing it across time from "the you who knows" (senses a need) to "the you who does" (is at the store). Or as asynchronous communication with yourself.

Why not have the detergent bottle automatically add itself to your list on your phone when it runs out - it doesn't need to actually buy it on amazon. Seems convenient to me.

And if you want to get even more techy, get a google home and say "hey google, add soap to my shopping list"

I wondered, can you do that? Because there are a million kinds of soap. Can you say "Hey google, add tide xt extra bright in the HD bottle" and it understands?

If a "home automation" product can't add arbitrary text to a shopping list (something my phone could probably have done in 2004) then what use is it?

Do you happen to sell "Tide XT Extra Bright in the HD bottle" soaps? Because if not, why would you even suggest that? :P.

I mean, seriously, I know what soap I want to buy when I'm shopping. It might be a different one every week. And I definitely don't want my automated solutions to vendor-lock me.

Oh - I thought it would actually order stuff, not just put it on a list.

But if its just making a list, then what's the point? I can write on the slip of paper on the fridge anyway.

The list idea was part of the "you really don't need this overwrought solution" thread. Oops I gave away the agenda!

Or I just buy the automatic laundry soap ordering thing.

This doesn't work for me. I've tried it many times and I run into the exact same problem, just half as often.

The way this works is: when you run out of your primary X and pull your backup X out of the closet, you immediately add X to the shopping list you carry with you. Then when you're in a shop, you simply buy things that are on the list and put them in the backup closet.

This requires developing two habits: 1) adding a thing to the shopping list when you fetch the backup item, and 2) actually using a shopping list.

Now I sympathize with the fact that different people have problems with different habits, so if it really doesn't work for you, then I guess you need something else :). But the benefit of this trick (or "life hack") is that it's free to use, doesn't require any purchase to set up, and doesn't tie you to any vendor.

If I forget that I don't have _any_ soap, what would make me remember that I'm out of my backup soap?

Also, why not just have this automated instead?

Automation means you actually have to run out to get more.

A backup bottle means you never are out - if you remember any time during the 2-month period it takes to use up a bottle. Or have an automated system.

Automation could mean it analyzes your average usage, and when you will run out in (amount of time it takes product to get to you + 20% for a buffer) it will order more.

Or hell, when you are at 50/25/10%, order another.

And if you are uncomfortable with it ordering it for you, it could just add it to a shopping list for you.

I've actually semi-automated this in the past by having Amazon ship me products on a regular schedule. Pricewise, though, it makes more sense to just make a quarterly trip to Costco and load up the storage closet.

Because you are not beholden to billions of dollars of infrastructure just "working".

Like our cell phones, or cars, or electrical grid? Silly, that's called 'civilization'.

I'm already paying for it, either through my free will (through various services) or threat of violence (taxes).

Amazon recurring delivery sends me laundry detergent, toilet paper, soap, etc. on a monthly schedule. It I get to much I can pause for a bit.

We do the same with K-Cups, very useful, and something you quickly take for granted.

I have noticed that we pay more over the longer term however as we miss sales/discounts/etc that you'd get by ordering in singles. Don't love that.

That's a good alternative, I agree - but still, I need to click things manually. Solution in OP is fully automated.

I agree with you, and I see that you get the normal responses I also get when I bring these things up (Just remember next time! Make a list! Buy two times as much then just remember you are running low!).

But when there is a technology that can make things better for us, allowing us to have to remember less and do less, why not?

I buy a specific brand of cat litter, laundry detergent, paper towels, and toilet paper. And all of them I often forget I'm low on until it's too late, and I need to run to the store for a single thing.

You can give me all the "solutions" in the world and i've probably tried them, this has happened my whole life.

But then a technology comes along and takes care of this for me, and people are upset that it exists!?

Yeah, the retailer the automation buys from could jack up the prices, if they do that I'll stop using it. Yeah, it could end up costing me slightly more for the convenience, i'm okay with that. Yeah, there are other solutions that work well for other people, they don't for me.

And besides, there are tons of other uses for this kind of thing. The software doesn't need to automatically order it if you don't want to, it could just make a list for you if you'd prefer.

Well, you can think of the "buffer method" (initially buy 2 units of an item, always add 1 unit to shopping list the moment you fetch the backup one) as a life hack, a piece of technology that's really awesome because it doesn't require anything than just a very small shift in your habits.

That said, I think people - myself included - complain about this example usage because of all the uses one can come up in 30 seconds, this one is the least generally useful, and most ridiculous one, and this is the one that the authors decided to run their story with. For me, frankly, it's a bit pathetic.

It strongly reminds me of another example - BLE beacons. There are plenty of useful applications that are also obvious when you understand what it is, but what was that the companies (I won't name a particularly well-known brand from my area[0]) decided to run with? Pushing ads into peoples' phones when they're shopping.

It's as if people are purposefully trying to not use technology for good, and instead focus on the worst parts of our culture - greed, consumerism and exploiting others.


[0] - There is also another, lesser-known BLE beacon brand in my area, which started their copy with industrial and medical uses. Well, after the success of the retail-oriented brand, they too decided to go with retail instead.

Maybe to you, but to me this is probably my favorite usage of this technology that I can easily come up with. In other words the way it will have the best impact on my day-to-day life (hell, if it stops the "run to the store for detergent" drives, it'll probably be better for the environment as well).

If this ever gets to the point where I can buy filament for it and print stuff myself, the first thing I'll be doing with it is hacking something together to order stuff as it runs out.

Just look at it from my perspective. To me it's like people saying they can use BLE for medical and industrial purposes, and everyone is shouting about how useless and anti-consumer it is...

I'm with you. I would not only like this detergent idea but would like counts/weights for things in my fridge, pantry, bathroom. So when I'm in grocery/Dept store..I can just look at my phone to see what I need or have Amazon order it automatically.

I could also know what I needed to buy for cooking meals that week. It would be super efficient.

When you are out, just order some more. When we were living in Beijing, they would have it delivered within an hour or two.

The consumer sector is a great way to make money. People love buying stupid gadgets. And people already schedule purchases on Amazon every month - the sensor method is just an extension of this to save money/prevent waste. Eventually, if any company actually tries to do it right, sensor-driven consumer goods will become the norm. There's too many actually productive uses for sensors in the home for it not to be pursued.

"Convince Me Why Washer Must Talk to Grill" https://www.eetimes.com/author.asp?section_id=36&doc_id=1323...

The other reason you only see this stuff in the consumer sector is that non-consumer use of IoT is a hot garbage fire. Mesh networks used for industrial sensor tracking at scale are shit, no matter what high or low level protocols you use, and nobody has developed standards ubiquitous and unencumbered enough for everyone to adopt. And everyone already has connectivity for the devices and sensors that need them.

"...save money/prevent waste"

until it malfunctions and buys me a few hundred dollars worth at once. Or gets hacked and buys someone else a few hundred dollars worth at once.

This already happens without IoT.

It's not about whether or not you want to have it. It's about monetizing you. These features could be included in products without your knowledge and could communicate with other surveillance devices (Echo, Smart TV, Google Home, etc.) to relay to advertisers and product vendors information about your use of the product. This in turn could be used to sell hyper-targeted ads such as ads for detergent that are timed precisely for when you are low on detergent.

Your attention is one of the most valuable products in the world. Sub-dividing and parceling off that attention in as fine-grained a manner possible is extremely profitable.

I'm really concerned about this. It's not ads I'm worried about but the long term potential for truly unethical misuse of this technology. Combined with AI this stuff could be used to build psychological models on every human. The potential for misuse by everyone from governments to criminals is just insane.

We are building the infrastructure for a hellish dystopia just to get people to click ads.

Hellish dystopia would at least be interesting, TBH. The current situation is pathetic. The way we're building our infrastructure is showing our worst side as a species. The capacity to screw others to get a little ahead. The total disinterest in how much aggregate damage one is causing for often very little personal gain. This is sickening to watch, and in fact it's also the same aspects that give rise to dystopian scenarios in real life.

> This in turn could be used to sell hyper-targeted ads such as ads for detergent that are timed precisely for when you are low on detergent.

I'm not really sure what the point of that would be?

Maybe my wife and I are in the minority, but we purchase exactly one brand of detergent, and we haven't switched in a very long time (that said, we switched to this detergent because it was less irritating to our skin than the other brand product we had been using).

We are pretty much the same with other products we buy on a regular basis; we don't brand hop unless there's a very good reason to, and sometimes we'll go out of our way to stick with a particular brand if we have to and can. We certainly don't do so because of advertisements (we don't watch television, and throw away the various adverts we get in the mail, and I only listen to NPR).

Maybe other people brand hop all the time because of a commercial they see. I'm not sure what to think about that, if that's the case

Consider the saying "you are the product" about these things. If you are the product who is the customer? Advertisers.

It's about selling to advertisers. It doesn't matter so much whether or not it would actually work, just that it offers ad vendors a new "blue crystals" feature to sell. Micro-targeting segments the market more finely, allowing higher prices to be charged overall while giving advertisers the illusion that prices are lower.

Just like crypto, unless you yourself code and design the thing, you can't trust it at all. This is what we're down to. I don't even trust operating systems anymore unless they are open source. Freaking Windows 10 is spyware.

I cringed at that as well! This is absolutely amazing tech why use it for such mundane and lame things? Especially, like you said, to order things for me automatically. I absolutely would never want something ordering more of itself on its own. I'd guess maybe they did it for funding? "See? Our product can make you money!"

Amazon already offers such buttons but I haven't used them. I can certainly imagine that being convenient, although I'd want them to be a) unbranded/programmable; b) optionally adding to a shared shopping list rather than directly ordering c) possibly a bit more subtle and/or smaller in size.

I also don't fully understand the attention given to home consumables in these kinds of IoT applications- for me devices like Amazon's one press ordering button thing are better for this type of problem as it keeps you in the loop while still saving you the time. It's actually the automated purchasing that saves me time - not the automated sensing that something is running out. I already see that incidentally (often as part of my day) and in a second. Edit: the physical re-ordering button I referenced is called the Amazon Dash; it's not exactly what I thought it was but it's pretty close.

> Why. Why why why do all IoT-related articles always use awful consumer goods examples like this.

because consumer goods manufacturers have the big bucks to throw at research like this

Yeah but to the retailers, it must sound great:

- Recurring revenue - Frictionless transactions - Vendor lock in

To a business, this stuff is irresistible. Of course consumers would hate this. But consumers also hated DRM, and they managed to shove that down our throats.

The application is not as important as the technology itself

Whenever I see those pointless uses of IoT, I pretty much just think of the SkyMall catalog. Lots of neat things that nobody will ever really use.

> Nobody, or next-to-nobody, would want to have that.

I think you substantially underestimate the apathy of the broader consumer market...

That's just the headline to make it relatable to a big audience. What would you use instead?

Doesn’t stop them from buying it. Even if my tech-illiterate friends are vaguely aware that e.g. “smart TVs” are, in fact, dumb as shit, they still prefer them to simple TVs.

It's not like they have a choice. That's the magic of the consumer market - people don't buy what they really want, they choose from what's available. Companies are focusing on improving smart TVs instead of offering dumb ones, so if one wants e.g. a good, high-tech display, one usually has to accept the "smart" "features" that come with it.

I dunno... I cook every day. I'd love a little gadget I can attach to my jug of olive oil or my sack of rice that will automatically ping Amazon to send more. Of course it's easy enough to do with my own eyes, but I'm usually too frazzled during and after cooking to update my shopping list...

So the solution is a better kitchen management experience / assistant / whathaveyou, not a dumb "smart" widget that fires off when you run out of oil.

"connect to WiFi" is not remotely accurate. It should be: "Reflect wifi signals in a predictable pattern." This technique, while impressive, requires custom hardware/software to detect and interpret (presumably via filtering and a fourier transform) the back-scatter signal.

Exactly. And when they say "Wi-Fi", they mean "2.4GHz signals". Wi-Fi is a protocol, and "connection" means bidirectional communication, which is not happening here.

I try to not nitpick too often, but things like this really irk me. And before someone says that it's a simplification for non-specialists - this is exactly the problem. Such stupid "simplifications" only serve to confuse people, instead of educating them. They promote fairy tales (easy to exploit later) instead of building an accurate model of reality.

Writing things like that is wrong, and hurtful to the readers. Writing things like that intentionally is simply malicious.

Yup, only plastic is also misleading since they need some conductive antenna. It's still very interesting and impressive, but somebody please fix the title.

This is really just a form of passive radar. It's using ambient signals instead of an active beam, but the analysis techniques used are essentially equivalent. It's like stealth technology in reverse. You are intentionally creating a recognizable radar signature.

All this to replace a slip of paper (aka "shopping list"). We have gone barking mad.

Ha, your cell phone is sort of like that. All that to replace, just waiting until you get home to make the call.

To be fair, this 3D trick also replaces remembering, driving, buying, restocking.

driving, buying, restocking

How so? You can already order online. All this devices replaces is the clicks it takes to do that.

A cellphone means you don't have to choose between receiving calls or going out. It's incomparable in its utility.

Replacing shopping list was but one of the use cases given. I agree it's a ridiculous one, but there's plenty of actually useful applications for things interacting with RF that can be mass-produced cheaply.

Ugh, just like all those trillions of man-hours spent making cars just to replace some simple horses. What a world we live in!

Well, horses are more renewable than petrol.... personally I think the jury’s still out on that one.

Just because people call it progress doesn’t mean the world is a better place.

Internal combustion engines are more important than just cars. They enabled powered flight. They enabled heavy construction and mining machinery. They enabled plenty of other high-impact things in our lives. And at the very least, they don't stink as much - towns eventually drowning in horse manure was a real fear in the times just before the first automobile.

That said, we're now on the verge of switching most of ICE uses into electricity, which can be made more renewable than horses. We'll be good, if we can make the transition.

The antenna is made of a conductive plastic.

From the article:

> In this case, the antenna is contained in a 3-D printed object made of conductive printing filament that mixes plastic with copper.

So this appears to be some sort of copper-plastic alloy that prints well and is conductive after printing. This part seems more revolutionary than the commercial aspect.

The article is incredibly light on detail. Making 3D printed items with switches in them is really easy. It's the receiver that's the hard part.

It would be great if they actually gave details. I want to know:

1. What device is receiving the signals. Is it commodity hardware (like a phone or laptop) or do they have to build a custom RF receive chain?

2. What software is used? What signal processing do they have to do? How does the software differentiate between one device and another one?

The interesting, ground breaking stuff is all in the electronics and software. The 3D printing stuff is fluff - it's just taking 100 year old technology and adding "3D printed" to it to make it seem modern.

Citations are always a researcher's best friend. The video has a URL researchers, http://printedwifi.cs.washington.edu/. That page has a paper PDF, with the following line:

> We note that prior electronic-based designs use both Wi-Fi signal variations (RSSI) as well as channel state information (CSI) variations [Kellogg et al.2014] to extract backscatter data. The backscattered signal from our 3D printed objects can be extracted using either of these procedures. Our implementation uses the MAX2829 802.11a/b/g transceiver that gives us access to the received 802.11g baseband signal.

Based on my time in grad school, I'm guessing they custom built a microcontroller for the task, and used that chip. There's a wealth of papers online dealing with backscatter, including the Kellogg paper cited above. Among their proposed setups is this fairly passive one:

> Finally, we check the feasibility of using only the periodic beacon messages from the AP. We use an Intel Wi-Fi Link 5300 card configured as the AP and an Intel Wi-Fi Link 5300 card as a Wi-Fi reader. The reader does not generate any traffic on the network and passively listens to the beacon messages periodically transmitted by the access point. No other device is associated with the access point, but it operates on channel 6, which is the same frequency as our organization’s Wi-Fi network.

Your other questions may be similar answered by following citations =)

Details from the paper itself [1]:

- uses MAX2829 802.11a/b/g transceiver - if WiFi preamble is detected, pass it further up the stack - otherwise normalise the signal and apply apply a 10th order 100 Hz low pass filter. - bitrate is 45bps :)

[1]: http://printedwifi.cs.washington.edu/printedwifi.pdf

OK, we've updated the headline by omitting words from this phrase from the article, “...3-D printing plastic objects and sensors that can collect useful data and communicate with other WiFi-connected devices...”.

Imagine a WiFi prism, where "light" (RF) waves are refracted into a specific pattern, separating channels into bands across a room.

Anyone that finds this interest should look at how “The Thing” (1945) worked: https://en.wikipedia.org/wiki/The_Thing_(listening_device)

EDIT: Here are some diagrams of how it works:


You should submit this as a HN link, really interesting story. Thanks.

I had heard of this, but didn't know its name, so never looked it up! Thanks for this link; very cool!

This is a truly awesome technology. But ITT an abundance of nit-pickiness on how this isn't exactly what the title says it is or how it could be presented better.

Yes, the nitpicks are correct. But wouldn't it be more inspiring to talk about how it could be used?

It's not that awesome. Miniature, WIFI-capable components with batteries that would last years already cost very, very little. This is a strange use of a low-tech approach, seems to fall under the "We can, but why would we?" category.

We're talking about that too; in fact, there's more talk about the usage than nitpicking about the description.

That said, to invent uses for a technology, one needs to understand what it does, and what it does not. Hence the nitpicking. This technology is functionally worse than regular RFIDs, but it's potentially dirt-cheap to manufacture. Saying it has anything to do with "Wi-Fi" or "connecting" is so deeply wrong that it heavily distorts one's understanding of its pros and cons.

"Without electronics" except for the computer devices that have to be dedicated to monitoring for the back-scatter created by the 3-D printed objects and translate it into something meaningful.

"Dedicated"? Can't the devices that is already nearby, like a router or your smartphone, query it when needed?

They can't query it, they have to be listening when it broadcasts.

Yeah ok I understand that it doesn't have a memory. But you can still sort of "query" the current state of a device that is always broadcasting, like a flow or speed sensor.

The router's probably pinging beacon frames out several times a second anyway. There's a lot of 2.4GHz traffic a passive listener could use.

You could presumably use existing devices for that, but it would require making a serious software change - in particular, you'd have to alter the radio driver to listen to and recognize backscattered signals (instead of rejecting them as noise).

This is a surprisingly simple solution to the problem: Make the working "device" (3D printed object) do as little work as possible - just enough to be detectable by the surrounding devices that are "real" computers anyway.

It's a bit like it sending out an audio signal (which would be another option I think) that can be interpreted by a receiver.

Audio signals were how the first wireless TV remotes worked [1]:

> In 1956, Robert Adler developed "Zenith Space Command", a wireless remote. It was mechanical and used ultrasound to change the channel and volume. When the user pushed a button on the remote control, it clicked and struck a bar, hence the term "clicker". Each bar emitted a different frequency and circuits in the television detected this sound. The invention of the transistor made possible cheaper electronic remotes that contained a piezoelectric crystal that was fed by an oscillating electric current at a frequency near or above the upper threshold of human hearing, though still audible to dogs. The receiver contained a microphone attached to a circuit that was tuned to the same frequency. Some problems with this method were that the receiver could be triggered accidentally by naturally occurring noises, and some people could hear the piercing ultrasonic signals.

[1] https://en.wikipedia.org/wiki/Remote_control#Television_remo...

This has been done - there are modules that detect and decode audio (which sounds a bit like R2D2). The manufacturer provides clips of this audio, which you could play from an app, allowing a phone to control something without it having to be on a network.

Unfortunately, AFAIK the technology doesn't have a searchable name, so I can't find anything about it now.

Of course, being able to listen for an arbitrary audio signal would be even more useful.

Here's a stupid idea I have (I'm pretty sure it's patented 'till kingdom come, but if not, then this is prior art and I want this to be public domain):

  (side view)

    +---+  BUTTON     +--------------------------------+
    |   |             |                                |
    |   +-------------+                                |
   -+ <-- valve                                        |
    |  +--------  -------------------------------------+
    |  |           flute          x x x x x x x x x x        <-- sounds comes
    |  +-----------------------------------------------+         out here

                                  x - a hole with an externally accessible
                                      lever that can be used to open or close it
Basically, you press the button, which pushes air through a flute, thus making a sound. The sound is configurable through pluggable holes (marked with x). In the diagram above there are 10 of them, giving you 1024 possible sound frequency combinations to listen for with your central IoT device.


- No electricity needed.

- Fully configurable, open source.

- 3D-printable maybe? Still, can be entirely plastic, so even more dirt-cheap to manufacture than the backscatter thingie.

- Less chance of interference - it's easier to keep the sound contained within your apartment than it is to keep radio waves.

That's not quite how flutes work. Two open tone holes in the same air column do not produce two distinct tones. They combine to change the effective length of the air column, which then provides a resonance for one tone, the frequency of which is determined by the length and the speed of sound, which in turn is mostly determined by temperature, and partly by the humidity. You still need a reed to produce the initial vibration.

I think what you are aiming for is more on the order of a disk siren. The rotation speed could be adjusted to produce a different base frequency, and one siren disk can support tone production from several air streams, each aimed at a different radius of the disk. Blocking off or opening the individual air streams can produce different chords based on the base tone.

If you have twelve speeds and six air streams, you can make 767 different chords. The same rotor can turn the siren disk and a fan to move the air. You press the button, the disk spins, and a pre-programmed chord plays.

Thanks for clarification. I never thought hard about how flutes work.

Still, based on your explanation, I feel that a fully-mechanical device that has hundreds of configurable tones and is operated through pressing a button should be feasible for easy mass-production and/or even 3D-printing.

In-band signalling?

I used to do the same thing with DTMF tones back in the 90's. The SSI202 was the hot DTMF to binary decoder chip.

Same concept, but the standard - I think it's a standard - I was thinking of encodes more data in a short time (using higher pitched sounds), as well as being more pleasant to my ears.

An example: having your IoT base listen for frequencies made by your kettle's whistle, or your washing machine's beeper.

Or your voice calling _"we are running low on soap"_.

Patent prior art right there.

Actually, I wonder how much those devices would interfere with the normal wifi, like "when the wind starts to move at higher speeds, my movie stops playing" ;-)

It's a clever idea, but without a 1:1 connection between an object and a network, it seems too dumb to be useful.

How is my WiFi network supposed to know that the interference in the signal came from my detergent bottle - not my neighbor's, and not from some other random object passing by? Do I have to do some sort of pairing every time I buy a new detergent brand to teach my network about it?

If pairing became an issue, amazon could associate a new bottle with your account before they ship it to you, and automagically register the device with your router. As an added bonus you could get a real confirmation that the box arrived when it is delivered.

This is a really interesting idea for IOT. I'm really excited by the possibilities it could open up.

Curious to see the impact this would have on wifi performance. Wouldn't this cause all of the really fun stuff making WiFi fast (beamforming, channel hopping, etc.) a lot less effective? Would be curious to see more information.

I imagine this would be really good for things like weather sensors or even security systems... but I have serious doubts of the efficacy of what they are doing.

Interesting tech but the consumer products example is broken to me because I don't want to be throwing out even more plastic.

It's a potential alternative to some IoT ideas, which have you wasting plastics and metals and powerful microcontrollers just to transmit a button press...

Seems like the main point is the antenna which isn't plastic, the rest could be build with wood too.

So my WiFi should easily be able to detect if my (all metal) garage door is open or closed? I would like this. I run dd-wrt. Is there an all-software solution to this? Or does this research rely on fairly specialized hardware? (sorry, didn't have time to read the whole article)

Probably, the first thing I thought about when I saw this was WiSee ("Whole-home gesture recognition using wireless signals"), which is also from UW: http://wisee.cs.washington.edu/

The research relies on special hardware, but you don't. I wouldn't be surprised if you could tell whether your door was open or not just from signal strengths of external wifi signals.

On reading the paper rather than the article: it's even simpler than I thought. No custom hardware necessary.

It requires a custom 3D-printed "device" on the door, which would modulate the Wi-Fi waves being scattered around (by your router, laptop, etc) into a signal that would indicate "open" or "closed".

I think the point was that the large moving metal object (garage door) itself would mess with the signal enough to detect the state without any additional device…

I guess a first good experimental step would be to point a directional Wifi antenna in the direction of the door and monitor what it receives at what strength.

Yup. And the actual implementation difficulty is in setting up the detection/analysis stack.

You could probably adapt this technique https://www.youtube.com/watch?v=aqqEYz38ens to detect your garage door state.

While rather impressive it sounds like a huge security problem to me.

With machine learning someone could probably train models that know what you are doing in your home.

Look at the other 3d sensing systems using Wifi by the University of Washington. It already is possible to form 3d pictures using microwave backscatter from ambient emissions.

I imagine they could quite feasibly do the same with the light that leaks out of your windows.

The level of security you seek is unattainable in practice.

Imagine 50 years from now inheriting a vase from your deceased relative that has been an undetected malware portal for decades! How exciting!

How can you hack something without software, electronics, and memory?

Since you worded that as a challenge... by maliciously modifying the CAD files that will be fed to the 3D printer.

...or by building an otherwise identical object that manipulates flaws in how the Wi-fi reads the signals and then replacing the original object with the malicious one.

Ignore the soap example and just focus on the underlying Wi-Fi backscatter technology. There are many applications in extreme low power or no power devices. Most are missing the point.

More details here. http://iotwifi.cs.washington.edu/

I am reminded of https://en.wikipedia.org/wiki/The_Thing_(listening_device)

This development will probably lead to a new combination of something like RFID, WiFi and electromagnetic power delivery (AM radio).

So what it is: mechanically modulated, very low frequency, passive microwave transmitter. No wifi anywhere there

How can this _possibly_ work? You can't make a connection to Wifi or implement any of the protocols that run over by passively reflecting some signals. All of them require some processing and two way communication. The article just makes no sense at all. It is 1st April?

It's explained in the article, although the title is inaccurate. The 3D printed devices do not, themselves, connect to WiFi. The backscatter is picked up by a WiFi receiver which is connected to the WiFi. But if you're going to comment, why not take the time to understand the article instead?

They use of "Wi-Fi" is itself a lie. It's not using Wi-Fi anymore than it's using Bluetooth or Zigbee. It's scattering back EM frequencies that happen to include 2.4GHz, which is a standard frequency for most consumer-level wireless communication.

I read and understood the article fully thank you. Wifi does not work like that and this cannot possibly work.

"this cannot possibly work" -- are you claiming that the working prototype depicted in the video is a fraud? That's a very serious allegation.

Cool idea, I'd like to see how much distortion this causes on the Wifi channels though. They are already overflowing.

As landfills pile up with wifi-reflecting garbage we will truly be realizing the dream of the IoS (Internet of Shit).

I’d imagine with conductive filament and a cheap microprocessor or bluetooth radio you can so the same or much more.

Its called an RFID tag

Which we technically call transponders, and while they do have EEPROM, they don't normally have CPUs.

yeah I was thinking they were powering a microcontroller via motion or ambient radio waves

>In first, 3-D printed objects connect to WiFi without electronics


Aww I remembered seeing this being presented in Siggraph Asia this year. Cool to see it popping up on HN now!

over-engineered stuff that does not really connect to anything! but needs a special device to permanently listen to signals from the 3d printed toy.

so, malware on my phone can fake these signals and order 200 gallons of laundry detergent for me?

Not sure at all how that would work. Can your phone generate arbitrary backscatter waveforms? I don't think it can.

If the malware could access and modify the radio driver then why not? Also, TX-capable SDRs are getting cheaper and cheaper :).

Radios are largely hardware in the TX component. Not a lot you can do but point them at data. I'm not sure ANY data pattern looks like backscatter?

Or the malware on your phone could... idk order 200 gallons of laundry through the amazon app on your phone? Seems a lot easier, I don't think the app requires authentication for purchases.

Or malware could just say "Hey Alexa [insert other name here]" and order detergent (This has happened accidentally in commercials).

> Or the malware on your phone could... idk order 200 gallons of laundry through the amazon app on your phone? Seems a lot easier, I don't think the app requires authentication for purchases.

it was just an example. If arbitrary, easy to replicate signals without an authentication start to represent meaningful device input, then that means anything that can generate these signals (such as maybe your phone, or maybe someone with a transmitter sitting in your driveway) can spoof your intent. It's like if someone could come into your house and start typing on keyboards.

and yes the example of speaking arbitrary voice commands to wake up alexas and google devices is a real problem too.

Zero security though.

Deceptive headline, please rename

You renamed it, but it is still does not indicate that the thing does 0 actual wifi protocol communication.

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