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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 i

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 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-mobile-chip-beams-data-for-miles-using-almost-no-power/ 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 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 https://youtu.be/4tmatoD0I1o?t=3m48s

detaro 9y ago
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)
- baldfat 9y ago
  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."
  - detaro 9y ago
    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.
    - baldfat 9y ago
      > 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 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.

detaro 9y ago

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)

baldfat 9y ago
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."
- detaro 9y ago
  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.
  - baldfat 9y ago
    > 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 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.