wow.. this girl is superhuman...
Mystery signal from a helicopter
21–30 of 83 posts
Re: Mystery signal from a helicopter
#22Nice bit of reverse-engineering, and an impressive hack from whoever built the system.
Quite funny - I know someone who uses a similar setup to send GPS Coordinates for a Quadcopter and a Plane via the audio channel of the video link (he flies the Quadcopter/Plane with video goggles) to the ground station. There, an Arduino controls some stepper motors to point directional antennas at the copter/plane. Project is at https://github.com/KipK/Ghettostation - video at https://www.youtube.com/watch?v=tiO4YC…
Cool! I hadn't seen that project before, although I'd seen a few other telemetry-over-audio solutions.
They usually use simple FSK just like the "real life" helicopter in the article.
Here's an example of a common simple protocol:
Re: Mystery signal from a helicopter
#23Can someone explain how she plotted the car's position? Did she manually reconstruct it based on the video and the information she derived from the helicopter's noise?
Re: Mystery signal from a helicopter
#24I love Oona Räisänen's blog. She's my hero. She combines a love of figuring stuff out with lots of fun hacks. And when I read her blog it makes me happy to see someone with that joy of uncovering mysteries.
You've probably already seen it, but in case you haven't: her talk at 30C3 was excellent and is worth a watch. https://www.youtube.com/watch?v=R-2k6TMPMRo
This was a fascinating talk. Thanks for sharing it.
Re: Mystery signal from a helicopter
#25Can someone explain how she plotted the car's position? Did she manually reconstruct it based on the video and the information she derived from the helicopter's noise?
I think so. It isn't a big deal to find the tennis courts in the beginning of the video:
https://maps.google.com/maps?ll=39.04082,-94.560871&t=h
I did that using her plots, but working backwards from the city hall to the freeway would only be tedious, not impossible.
Re: Mystery signal from a helicopter
#26Amazing!!! I would have just dismissed it as static interference, and not even think twice. Hmmm, makes me think twice about the beeping sounds I hear when my phone is right next to my radio. I know it's data being transmitted/received, but I wonder if it can be deciphered in this manner.
It's the phone checking in with the base station. As someone who records sound for a living, this is one of the banes of my professional life - I tell people on film sets to turn their phones off, and they think I mean 'don't use your phone' whereas in fact I mean 'shut it down completely.'
Re: Mystery signal from a helicopter
#27Nice bit of reverse-engineering, and an impressive hack from whoever built the system.
Using spare audio capacity like this is actually very common - prior to digital recording, engineers would dedicate one tape channel to recording a sync signal, and in mission-critical applications would even 'stripe' the tape with the sync signal beforehand (many pro recorders can have recording and read heads active simultaneously).
Re: Mystery signal from a helicopter
#28this is rad.
Re: Mystery signal from a helicopter
#29I'd had a copy of her dialup decoded poster on my wall for a while; forgot where I found it but it was immediately something I wanted to hang up... glad to see its being monetized via poster sales, its quite a lovely work of art.
Of course, I also find chip tape outs beautiful, much to my wife's dismay.
http://vlsiweb.stanford.edu/~jaeha/chip_gallery.htmlRe: Mystery signal from a helicopter
#30I love Oona Räisänen's blog. She's my hero. She combines a love of figuring stuff out with lots of fun hacks. And when I read her blog it makes me happy to see someone with that joy of uncovering mysteries.
Reading it now for the first time, super fun.
e.g., about those restaurant light-up/buzz pagers: http://www.windytan.com/2013/09/the-burger-pager.html