Key Fob Security

Discussion in 'Gen 5 Prius Main Forum' started by Hans Unrat, Nov 18, 2025.

  1. RandyPete

    RandyPete Active Member

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    I thought the last Gen 3 was a 2009 model !?

    OOPS,I was thinking of a Gen 2 !
     
  2. ChapmanF

    ChapmanF Senior Member

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    The ordinary cookie tin I'm using is quite effective, can take it within inches of the car and still no entry.

    I made an earlier attempt with a locking metal key box that I lined obsessively all around the hinges and gaps with conductive foil tape. Never got it to be effective.
     
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  3. futurist

    futurist Member

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    That's interesting -- the Faraday cage box I use has a mesh in it (Amazon seller sent one damaged, so they replaced it and I got to dissect the broke one). Supposedly the pitch of the mesh has to do with how much RF it can block (like how the see-thru perforated screen on your microwave oven door keeps the magnetron's RF in)... so the finer it is, the more effective for more frequencies. But if the can works but the metal box doesn't... perhaps the flat sides of the box are actually amplifying the signal instead of blocking it? And the open can's only leak is directly upward?

    Guess some commo engineers will need to chime in; eager to learn why :coffee:
     
  4. ChapmanF

    ChapmanF Senior Member

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    For clarity, I don't use the cookie tin open. It has a reasonably tight-fitting lid, painted with green foliage and a floral wreath.
     
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  5. dbikedoc

    dbikedoc Junior Member

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    If you hold the key fob lock button down while pressing the unlock button twice, you will shut off the radio transmitter in the fob. The LED will blink twice indicating it worked. Reactivate fob by pressing any button. I’m sure it works because I’ve walked up to my car having forgotten to reactivate & it won’t unlock. This also saves battery in unused fobs. Not transmitting at all is safer than Faraday cage.
     
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  6. dbikedoc

    dbikedoc Junior Member

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    If you hold the key fob lock button down while pressing the unlock button twice, you will shut off the radio transmitter in the fob. The LED will blink twice indicating it worked. Reactivate fob by pressing any button. I’m sure it works because I’ve walked up to my car having forgotten to reactivate & it won’t unlock. Not transmitting at all is safer than a Faraday cage. This also saves key fob battery.

    Sorry for duplicate. Thought I was editing original.
     
    #26 dbikedoc, Dec 7, 2025 at 12:41 PM
    Last edited: Dec 7, 2025 at 1:33 PM