It hasn’t become a household term yet, but Software-Defined Radio (SDR) is a major player on the developing technology front. Whether you’re building products for mass consumption, or just playing around for fun, SDR is worth knowing something about and I’ll prove it to you.
[Spock] wanted to do a little reverse engineering of his Miele brand remote control vacuum cleaner, so he broke out his DVB-T SDR dongle to use as a spectrum analyser. Sure enough, he found a 433.83Mhz signal that his vacuum cleaner remote control was using, but to his surprise, he found a stray
QAM256 signal when he expected an ASK only one.
After a little detective work, [Spock] eventually tracked it down to a cheap weather station he had forgotten about. The protocol for the weather station was too compelling for him to go back to his vacuum cleaner, though. After
downloading an rc-switch Arduino library and making a quick stop at his local radio shack to get a 433.92 radio receiver to decode the signal, he reverse engineered the weather station so he could digitally record the temperature output. The Arduino rc-switch library proved unable to decode the signal, but some Python work helped him get to the bottom of it.
With software defined radio becoming more accessible and common place, hacks like these are a nice reminder just how wired our houses are becoming.