“One of the higher-frequency harmonics inevitably created by any real-world DAC during playback will then be the original fundamental, which should leak to the environment as a short-range radio transmission via the ad-hoc antenna formed by the physical wires and circuit traces in the audio output path.”
Sometimes I think I’m a smart guy…and then I read of people doing shit like this.
I once programmed my TI-84 calculator to do exactly this! The only missing thing was a circuit to convert the audio jack output voltage into the needed form for an antenna. I had the CS know-how but no EE know-how, so I never got it to work. It was fun to dream about confusing my high school's clocks though. (Sadly, the other obstacle was that the clocks only listened for the signal overnight, which improved their chances of detecting the weak broadcast out of far-away Colorado.)
> audio jack
That's a serial port, except when you're playing Bad Apple
You can apparently lock shopping trolleys using the same kind of principle - https://www.tmplab.org/2008/06/18/consumer-b-gone/
I can't tell if I'm fooling myself or if this actually (partially) worked. Is it possible for only the hour and seconds to sync if the signal isn't perfectly received? How long is it supposed to take to sync the time? Is it possible that this can confuse clocks when the phone is nearby, but otherwise still getting the real signal?
I just tried it on a clock that has only ever successfully synced once many years ago, and it's still in the same bad location that doesn't get a good signal.
Its crappy little LCD animation did indeed seem to dance in sync with when I would turn the signal on and off on my phone. It took a few minutes of trying but then suddenly the hour and seconds updated to the exact time. Had to set the minutes manually :/
Shame there's no video demonstrating it working. It's a fun idea but without a demo, I'm left wondering about the efficacy.
I wasn't able to get this to work on a Pixel 8 in Chrome/Firefox on a JP region clock
This is pretty darn cool, but I have to say I was somewhat let down by the WWVB signal. I was expecting the entire audible range instead of simply the extracted data. That being said, that's also really darn cool.
I find the WWV/WWVB droning soothing somehow.
Err… WWVB has no audio range. The carrier frequency is only 60 kHz. It’s effectively a CW signal since the amplitude is only modulated once per second.
There is an audible setting in the app that shifts the signal down to human range.
Here's an emulation of WWV I did with a transmit capable SDR.
And the 2024 lateral thinking award goes to...
Ha, there's one radio clock in my house that I still keep going for sentimental reasons... it's had a rough time setting itself for a few years, likely due to its placement in the house.
I'll have to test this out sometime, what a fun idea!
What? Wow
Whenever I see things like this, my first thought is that somebody is going to write something to mess up nearby atomic clocks, just because they can, then I think- why, why did you do this?
Then someone will respond: you’re just catatrophising- anyone could’ve done this years before now, and I’ll say no, because it wasn’t up on frontpage HN there with code so that anyone would think of it. Then they’ll say, well why did you tell everyone that idea then! It’s your fault! Then I’ll say that someone would’ve done it if it weren’t me. Then I’ll go have a beer.