[HN Gopher] Energy-Harvesting Electronic Holiday Card 2024
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Energy-Harvesting Electronic Holiday Card 2024
Author : teuobk
Score : 161 points
Date : 2024-12-12 21:00 UTC (2 days ago)
(HTM) web link (www.keacher.com)
(TXT) w3m dump (www.keacher.com)
| mmastrac wrote:
| I read the technical description of this and the whole work seems
| like magic. Antenna design, extremely low-power passive networks,
| etc. On top of that, it can tap into network signal bursts as a
| communication medium.
|
| It feels like a project sent from the future.
|
| I've always been curious what energy harvesting systems are
| capable of.
|
| Also, what is the third type of energy harvesting besides light
| and 2.4GHz? I couldn't figure out what that might be.
| jotux wrote:
| Heat, voltage drop, and vibration are some other methods.
| mmastrac wrote:
| This card apparently has three - but none of those additional
| ones you listed, unfortunately.
| yojo wrote:
| "At its core, the card harvests energy from light, radio,
| and/or a USB connection to enable the blinking of LEDs."[0]
|
| So the last is USB, the sneakily obvious one.
|
| 0: https://www.keacher.com/xmas24/tech_info.htm
| ggm wrote:
| Back in the days of 2G the pre-wake-up pulses, aside from causing
| massive FM/AM interference like demented Morse code, would light
| up tuned antenna spark gaps on stickers for your Nokia phone. In
| Japan they sold cute phone tokens which had glowing eyes.
|
| Energy harvesting the same way Theremin did for his passive wall
| bug.
| taneq wrote:
| Tuned spark gaps? Or just an antenna hooked up to a pair of
| back to back LEDs? Just recently I saw something about light-up
| fake fingernails that would blink when you got a 2G phone call.
| ggm wrote:
| Probably the LED.
| Analemma_ wrote:
| I remember when you could tell you were about to receive a
| cellphone call based on radios and other analog electronics
| behaving weirdly. I got various people thinking I could see a
| few seconds into the future.
| a_t48 wrote:
| For a while I had a very overpriced phone case from moeco that
| lit up when cell service was being used -
| https://www.moeco.jp.net/ - it came with a big warning not to use
| wireless charging with it (due to instead heating the case).
| Sadly, I wouldn't get one nowadays, I love wireless charging too
| much.
| yapyap wrote:
| lol screw wireless charging, if I had the $$ for it and
| shipping and taxes wouldn't be so darn expensive it'd be a
| nobrainer for me
| Washuu wrote:
| It's only for the iPhone and still 17,600Yuan though. Gao
| idesune!~
| illwrks wrote:
| This is the same principle as those mobile phone led flashing
| stickers from the 90's/00's.
|
| Clever idea.
| roger_ wrote:
| Interesting, thanks for sharing.
|
| One question: what load is the matching network designed for? Did
| the designer find the equivalent small signal impedance of the
| diode network via simulation? Is the SPICE model even valid at
| 2.4 GHz? Is small signal even applicable?
| trebligdivad wrote:
| very nice! They mention the use of Barker codes, which I'd not
| heard of before;
|
| https://en.wikipedia.org/wiki/Barker_code
| jasonjayr wrote:
| This is super neat. By modulating the _timing_ of the data being
| sent to a websocket, (which is basically a /dev/null data sink)
| it implements a covert air-gaped side-channel data transmission
| mechanism.
| myself248 wrote:
| That's the part that's blowing my mind. Energy harvesting is
| cool and tricky to get right, but it's not magic.
|
| Sending data by modulating the data flow itself, is spooky.
| Absolute madness. I love it and I'm a little scared.
| pcdoodle wrote:
| This project is so inspiring. I just spent about a half hour+
| oogling over the details. Great documentation and I learned about
| so many things.
| mschuster91 wrote:
| > That last one consumed an hour of diagnostic time and involved
| using time-domain reflectometry (with a 20 ps rise-time pulser
| and 20 GHz scope) to locate the fault to within a region of a
| couple millimeters on one trace.
|
| How does one even obtain the skills, much less the _equipment_ to
| run such precision?!
| pjc50 wrote:
| A good EE degree with some RF specific course parts will teach
| you the concept. The scope .. well, you kinda have to borrow it
| from your employer as they're in the $10k range at that
| frequency.
| myself248 wrote:
| They also mention having access to a source-meter, which is
| not cheap either. I wouldn't mind spending some time in that
| lab!
| ninalanyon wrote:
| Reminds me of an old Nokia proof of concept charger for a mobile
| phone that used energy harvesting. It never was enough to make a
| call though:
|
| From 2009 https://www.eetimes.com/nokia-working-on-energy-
| harvesting-h...
|
| But it seems that the idea is still alive, from 2023:
|
| "Relying more on ambient energy sources could prove monumental in
| automated warehouse inventory tracking, in medical instrument
| management and for deployment in airports, shopping centers and
| even individual smart homes. Nokia's goal is to have energy
| harvesting technology in cellular networks that can support this
| massive IoT deployment."
|
| https://www.nokia.com/blog/the-future-belongs-to-zero-energy...
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(page generated 2024-12-14 23:01 UTC)