very nice! They mention the use of Barker codes, which I'd not heard of before;
Energy-Harvesting Electronic Holiday Card 2024
11–20 of 26 posts
Re: Energy-Harvesting Electronic Holiday Card 2024
#12This 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.
Re: Energy-Harvesting Electronic Holiday Card 2024
#13This project is so inspiring. I just spent about a half hour+ oogling over the details. Great documentation and I learned about so many things.
Re: Energy-Harvesting Electronic Holiday Card 2024
#14> 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?!
Re: Energy-Harvesting Electronic Holiday Card 2024
#15> 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?!
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.
Re: Energy-Harvesting Electronic Holiday Card 2024
#16For 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.
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
Re: Energy-Harvesting Electronic Holiday Card 2024
#17This 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.
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.
Re: Energy-Harvesting Electronic Holiday Card 2024
#18> 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?!
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.
They also mention having access to a source-meter, which is not cheap either. I wouldn't mind spending some time in that lab!
Re: Energy-Harvesting Electronic Holiday Card 2024
#19Reminds 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...
Re: Energy-Harvesting Electronic Holiday Card 2024
#20Back 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.
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.