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Batteryless wireless tranceivers

Added by haarts over 5 years ago

Hi all,
Today I read about “ambient backscatter”, a way of communicating wirelessly via energy scavenging. I figured I’d share it here:
http://homes.cs.washington.edu/\~gshyam/Papers/amb.pdf
https://news.ycombinator.com/item?id=6004470

I’m wondering how quickly this could be put into production. I don’t see major objections. Thoughts?


Replies (3)

RE: Batteryless wireless tranceivers - Added by martynj over 5 years ago

haarts, a very interesting paper, thank you for the link. The mechanism used seems quite limited in distance (which makes intuitive sense since extracting or not some portion of the broadcast signal several wavelengths away has a vanishingly small effect on the locally received signal). The paper does illustrate effective communication at close range though which would match some application classes. An alternative to terrestrial TV broadcasts would be to tap into the RF energy from a local WiFi mesh - with the higher band, the aerial dimensions are scaled down correspondingly.

Summer project anyone? ;-)

RE: Batteryless wireless tranceivers - Added by padvinder95 over 5 years ago

Indeed a very cool idea, for very short range communication. Does it have economical feasibility? I don’t know—they are semi-active devices, so a regular RFID tag might be cheaper and just as suitable for the short-range identification-type of communication.

What I especially enjoyed is the envelope detection+low-pass filtering of the signal, all done in the analogue domain, using a double RC circuit and a comparator to directly demodulate the signal!

RE: Batteryless wireless tranceivers - Added by haarts over 5 years ago

martynj I’d love that summer project! Not that I have time to invest… Depending on a couple of factors I might take you up on it.

padvinder95 I very much believe it has commercial viability. There are three issues; the cost, the range and the fact they do nothing else but transmit.
# They have made 20 prototypes for \$45 each. Stupidly expensive of course. But these are prototypes. I believe (not based on anything but a gut feel and that they mentioned using only of the shelve components) that the cost could be something like a 1/10th perhaps even a 1/100th of that. Imagine what the latter will do? You could produce stickers doing this. Bad reception? Slap an other sticker on! Also; no crippling licensing fees.
# It’s a prototype! Get crazy on the antenna etc etc and I believe range can be much better (twice? tenfold?). In effect increasing the range reduces the number you need which reduces the cost.
# I don’t know how much it takes to make an ambient light reading, or a temperature reading, or trip a PIR, or sense humidity, or measure sound, or measure draft/wind. But I can imagine that not being much. Also once every 5 minutes is good enough.

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