Smart key disruption

Discussion in 'Gen 2 Prius Main Forum' started by Kablooie, May 28, 2005.

  1. Kablooie

    Kablooie Member

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    I tried opening my locked car the other day but it wouldn't respond. The smart key was in my pocket as usual.

    I took off my headphones and inspected the fob. It seemed OK. I tried pressing the button and the door unlocked right away.

    I relocked the door and put the fob back in my pocket and tried again. No luck. It wouldn't unlock.

    I was starting to get concerned when I realized that my ipod was in the same pocket. I took it out and the fob unlocked th door just fine. I put the ipod back in and the fob wouldn't work.

    Moral: Don't let your fob become to close to your ipod or they may decide to ignore you.
     
  2. oly_57mpg

    oly_57mpg New Member

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    Considering that the Prius SKS, keyfob, and the Ipod both conform to FCC part 15; they will both accept the RF radiation from each other. Thus, canceling each other out.

    It's more likely that the transmit frequency of the keyfob is about the same as one of the processors in the Ipod. There was just too much noise in the 'band' to broadcast. Same idea behind signal jamming.

    The keyfob transmits at 312.5MHz and has bandwidth of 780.375KHz.

    Tokai Rika designed the Prius keyfob in 2003.
     
  3. Blue

    Blue New Member

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    Cell phones can cause a similar problem. For example, I am unable to lock the doors using the fob or the handle button if I leave my cell in the Prius. If I lock the doors using the power lock located inside the door, then close the door, the Prius will unlock the doors automatically.

    I suppose it could be considered as a gentle reminder not to forget your cell.
     
  4. oly_57mpg

    oly_57mpg New Member

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    Humm... There's something that's not right about that. Who is your wireless service provider? Verizon? They're the only provider that has phones that emit that much RF radiation.

    Not all phones cause the problem you describe.
     
  5. Frank Hudon

    Frank Hudon Senior Member

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    It happens to my wife and her cell in her purse and if it's between the fob and car, better get her a hammer to break the window cause she isn't getting in.
     
  6. tag

    tag Senior Member

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    Yep........something's not right BUT, whatever it is, it certainly doesn't have anything to do with Verizon.

    I have a V710 (SAR at ear = 1.40) and have had an extremely difficult time reproducing the one SKS interference incident I encountered. I have placed the fob and phone in direct contact with each other, in differing positions, and the car still powers up.

    As an aside, FWIW, both Cingular and Verizon have the Treo 650 and both have the same SAR despite the fact that one is GSM and the other CDMA.
     
  7. oly_57mpg

    oly_57mpg New Member

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    Yeah, you're probably right. But I've been witness to many RF problems associated with Verizon...
     
  8. Blue

    Blue New Member

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    It's actually Cingular, with a Sony Ericsson T637 Bluetooth phone.
     
  9. brandon

    brandon Member

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    Power lines can cause similar problems. After washing my Driftwood, I parked next to a power transformer and began to dry it off. The vehicle occasionally locked itself (did not unlock itself, though). I moved it away from the transformer, and the odd behavior disappeared.
     
  10. Frank Hudon

    Frank Hudon Senior Member

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    <div class='quotetop'>QUOTE(brandon\";p=\"93718)</div>
    the car will do that if you have the fob in your pocket and the car is still wet and you are drying it near the door handles. Had this happen lots of times. Now I just throw the fob on the seat and dry the car.
     
  11. xevious

    xevious New Member

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    Does anyone know what frequency the SKS uses? My guess would be the 902-928MHz ISM (US) band, which is very close to two cell phone bands (930MHz and 1800MHz). Not every cell phone uses these bands; there are several others available in the US.

    I would guess that the very weak SKS signal (1-2dBm) is experiencing interference from a nearby stronger (~5-23dBm, depending on mode) cell phone signal.

    Or, the cell phone's signal could be effectively jamming the SKS fob's receiver and confusing the fob's MCU. Much more likely scenario.

    Keep them in different pockets and see what happens.
     
  12. prius04

    prius04 New Member

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    Has anyone considered the possibility that the reason the FOB didn't work with the iPod was because the FOB was too busy listening to the music?

    Rather than putting the devices in different pockets, how about trying show tunes, then rap, then c&w, then heavy metal then throw in a podcast of Rush L then Al F.
     
  13. geckoboi78

    geckoboi78 New Member

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    <div class='quotetop'>QUOTE(oly_57mpg\";p=\"93659)</div>
    Actually I have the same exact problem and I have sprint. They also address this in the manual and forewarn you that cell phones and other devices can interfere with the key fob if kept together in the same place such a a purse or pocket.
     
  14. oly_57mpg

    oly_57mpg New Member

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    xevious -

    Please read my post above.

    Nope. Not even.
     
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