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X-band motion detector as a "speed gun" — Parallax Forums

X-band motion detector as a "speed gun"

legoman132legoman132 Posts: 87
edited 2011-11-28 11:33 in Accessories
I was wondering if anyone had some idea about getting approximate velocity from the cycles on the X-band sensor's OUT pin. Im not even sure if this is possible, but any help would be appreciated!

Post Edited (legoman132) : 4/22/2010 11:35:09 PM GMT

Comments

  • kwinnkwinn Posts: 8,697
    edited 2010-04-24 15:05
    It is possible. This is how the original (rf) radar guns worked. The output frequency is proportional to the speed of the approaching object. To calculate the actual velocity of the object is not that difficult.
  • ElectricAyeElectricAye Posts: 4,561
    edited 2010-05-02 03:27
    legoman,

    have you had a chance to try this out yet? I'm curious to know if it works. smile.gif
  • logan996logan996 Posts: 281
    edited 2010-05-02 18:29
    yea some one take this on! this would be great! if someone tries, this post it here!

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    "When the government is afraid of the people there is liberty, when the people are afraid of the government, there is tryanny"

    · Thomas Jefferson
    ·
  • artie123artie123 Posts: 5
    edited 2011-11-28 11:33
    If anyone takes this on as a project, they should begin by removing the Parallax signal processing module and taking the raw analog signal from the rf module itself.

    Some other info that might be helpful.........

    The module is actually 2 modules. One of the modules is an HB100 DRO module, which is a complete transceiver with a single output which is (an analog low level) the difference frequency (frequency is proportional to speed). The second module takes the small analog output of the rf module and converts it into digital data that a microcontroller can use for detecting motion. The second module is the parallax created PCB that is piggybacked onto the rf module.

    The rf module is available on ebay for prices ranging from 2 or 3 dollars up to 12 bucks, There is some technical info on the web regarding hacking of the Mattel radar gun, which uses the same technology. Anyone interested in this as a project should start with google.

    Enjoy.
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