From vacuum cleaner hacking to weather station reverse engineering

spectrum

[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.

Comments

  1. Andy says:

    I don’t think there was any QAM discovered, I think that was a tongue-in-cheek comment by the author. It appears that both the vacuum and the weather station used on-off keying (OOK), which is not surprising.

  2. tekkieneet says:

    [Abe]‘s summary is misleading and makes it sound like Audrion library saves the day.
    “After downloading an rc-switch Arduino library and and making a quick stop at his local radio shack…”

    Original article:
    >I found Fred’s webpage, and rc-switch Arduino library. I looked into source files and none protocol was similar to mine.

    So it would be more like “after *ruling out* rc-switch Arduino library, [Spock] made a quick stop at his local radio shack…” or remove the Arduino reference all together.

  3. Velli says:

    The amazing part of this story is that he found a component he needed at RadioShack.

  4. JimBob says:

    What is this fondness for strikethroughs the writers here have? Doesn’t their editor have a “delete” function?

    • Me says:

      Strikethoughs are a better way to ‘delete’ something when an article has already been posted and viewed by people. Otherwise you get a helpful post that something needed to be changed followed by 20 or so non-helpfull replies by people who don’t know what the original commentor was talking about because they see the now-edited version.

  5. Telek says:

    “a nice reminder just how wired our houses are becoming”

    Don’t you mean how _wireless_ our houses are becoming? :-)

  6. michael says:

    cool, great ide to use what is within reach in our home ;)

    I use cheap 433 Mhz RX/Tx modules with arduino, or the full duplex rf12b module.

    I made two ‘hello world’ sketches for arduino RX/TX http://techmind.dk/arduino-singleboard/rf-tx-rx-433mhz-wireless/

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