3 ms·

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.

TeMPOraL 9y ago
The technique you mention is realized through an FPGA chip. It is not used in the 3D-printed backscatter devices this article is about.
- baldfat 9y ago
  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."
detaro 9y ago
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.
- baldfat 9y ago
  Backscatter is the same technology in both projects. Yes, scientifically they are new packets. See https://youtu.be/4tmatoD0I1o?t=3m48s 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.
  - detaro 9y ago
    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 http://printedwifi.cs.washington.edu/printedwifi.pdf and Hitchhike https://web.stanford.edu/~pyzhang/papers/sensys16_back_comm.pdf https://web.stanford.edu/~pyzhang/papers/sensys16_back_comm.... or interscatter http://interscatter.cs.washington.edu/files/interscatter.pdf 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.
    - baldfat 9y ago
      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 https://en.wikipedia.org/wiki/Modulation

TeMPOraL 9y ago

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

baldfat 9y ago
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."

detaro 9y ago

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.

baldfat 9y ago
Backscatter is the same technology in both projects. Yes, scientifically they are new packets. See https://youtu.be/4tmatoD0I1o?t=3m48s 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.
- detaro 9y ago
  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 http://printedwifi.cs.washington.edu/printedwifi.pdf and Hitchhike https://web.stanford.edu/~pyzhang/papers/sensys16_back_comm.pdf https://web.stanford.edu/~pyzhang/papers/sensys16_back_comm.... or interscatter http://interscatter.cs.washington.edu/files/interscatter.pdf 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.
  - baldfat 9y ago
    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 https://en.wikipedia.org/wiki/Modulation