Give a software-defined radio (SDR) platform to a few thousand geeks, and it’s pretty predictable what will happen: hackers gotta hack. We’re only surprised that it’s happening so soon. Spectrum Painter is one of the first cool hacks to come out of the rad1o badge given out at the CCCamp 2015. It makes it dead-simple to send images in Hellschreiber mode on a few different SDR hardware platforms.
What we especially like about the project is its simplicity. Don’t get us wrong, we’re tremendous fans of GNURadio and the GNURadio Companion software radio hacking environment. But if you just want to do something simple, like send a picture of a smiley-face, the all-capable GNURadio suite is overkill.
HackRF, the rad10 badge, and bladeRF all have software that enables you to directly load up and play out a file over the radio interface; it’s like a WAV file, only at radio frequency. This makes a hack like Spectrum Painter pretty straightforward. Simply convert the image file into the corresponding radio waveform data, and send it along. No GUI, no dragging, no dropping.
img2iqstream -s 1000000 -l 0.004 -o smiley.iqhackrf --format hackrf examples/smiley.png hackrf_transfer -t smiley.iqhackrf -f 2450000000 -b 1750000 -s 1000000 -x 20 -a 1
Bam! Kudos [polygon]!
If all of this SDR action has your interest piqued, there’s a lot you can do even just receiving with an el cheapo RTL-SDR USB stick. It’s the gateway drug into SDR, so if you’re not addicted yet and you’ve got a free weekend, give it a shot.