1. Attachments are working again! Check out this thread for more details and to report any other bugs.

Test the fob and EM wave

Discussion in 'Gen 2 Prius Main Forum' started by ScottY, Jul 13, 2005.

  1. ScottY

    ScottY New Member

    Joined:
    May 18, 2005
    1,250
    7
    0
    Location:
    Long Island, NY
    Vehicle:
    2005 Prius
    Just curious myself, I wanted to do a test and try to block the communication between the fob and the car by blocking the EM wave.

    First, I used the electrostatic shield bag (silver-ish looking ones). As I was told, these bags have conductive coating on its surface and will block RF wave. Which make sense because EM wave can not exist inside a perfect conductor. I put the fob in the bag, went to the car and open the door (FYI, I have SKS). The door opens! Then I go ahead and turn on the car, and it worked!! :roll: Which kinda surprised me, I guess nothing's perfect (referring to the conductive coating on the bag) :wink:

    Then I wrap the fob in aluminum foil. This time I was not able to open the door. I entered the car with the mechanical key. I tried to turn the car on, but the yellow key icon in the dash light up and beep once, telling me the immobilizer really works! :D I unwrapped the fob and started the car. After that, I wrap the fob in the foil again and drive. I thought the car will not drive without sensing the fob, but it did! :cussing: So the immobilizer only works when you try to start the car. I expect it to work at all times... but oh well. :|

    Just a little experiment I did and like to share with you guys. Have fun driving.

    ps. if anybody got answer to my alram question, feel free to reply here:
    http://www.priuschat.com/forums/passive-al...on-vt10253.html

    Scott
     
    #1 ScottY, Jul 13, 2005
  2. plusaf

    plusaf plusaf

    Joined:
    Feb 15, 2004
    324
    5
    0
    Location:
    Raleigh, NC
    Vehicle:
    2004 Prius
    Model:
    N/A
    <div class='quotetop'>QUOTE(ScottY\";p=\"106952)</div>
    you were told wrong. sorry for mis-set expectations. those silvery coated plastic bags are exactly what you said they were: anti-static. they conduct electrical charge so that the stuff inside doesn't get zapped. electric charge can build up only on the outside of a conductive body, not on the inside.

    you could consider it to be "not conductive enough" to block electromagnetic waves, which a conductive layer of metal can usually do, for shorter wavelengths like radio waves.

    the electrostatic shield isn't really any kind of wave at all, but just a charge buildup.

    easily confused by the media and folks who haven't been beaten to a pulp already by a degree in electrical engineering or something like that...

    :)
    enjoy!
     
    #2 plusaf, Jul 14, 2005
  3. ScottY

    ScottY New Member

    Joined:
    May 18, 2005
    1,250
    7
    0
    Location:
    Long Island, NY
    Vehicle:
    2005 Prius
    Actually, I was told these bags will shield against RF waves at an ESD (Electro-Static Discharge) Training course in my company. Unless the EM wave emitted by the Prius is totally different in characteristic than the "RF wave" that's present in my company. My assumption is that the EM wave emitted by the Prius is longer in wavelength, therefore can penetrate through the static-shield bag. Usually longer wavelength EM waves can penetrate deeper into a material (still faintly remember the concept of "skin depth" in an EM related course in college).

    Scott
     
    #3 ScottY, Jul 14, 2005
  4. Marlin

    Marlin New Member

    Joined:
    Jun 20, 2005
    1,407
    10
    0
    Location:
    Bucks County, PA
    Vehicle:
    2005 Prius
    Why is this an issue for you?

    Do you want the car to shut off on the highway because your fob battery finally died because the car polled it every 3 seconds while you were driving?

    YOu can even get out of your car and walk away and the car will stay on. It will beep at you as you walk away, but it will stay on anyhow. I find this to be a good thing. It means that I can get out of the car and run into the house or a store while my wife and daughter stay in the air-conditioned car, without having to take my key out of my pocket and leave it in the cup holder.
     
    #4 Marlin, Jul 14, 2005
  5. ScottY

    ScottY New Member

    Joined:
    May 18, 2005
    1,250
    7
    0
    Location:
    Long Island, NY
    Vehicle:
    2005 Prius
    Your thought about the car on the highway is a good point. I am not saying I want the car to shut off, but I thought the immobilizer will not let the engine run without sensing the key fob at anytime. Let say I just started the car in my drive way, but went back in my house to get something. I don't want somebody to drive it away. I guess I am being too paranoid. :roll: But who isn't paranoid about their Prii?!!
     
    #5 ScottY, Jul 14, 2005
  6. priusman88

    priusman88 Junior Member

    Joined:
    Jan 24, 2004
    18
    0
    0
    I have found that my iPod actually interferes with the functioning of my key fob. If I put my iPod in the same pocket as my key fob, the fob doesn't work.

    It took me a while to actually figure this out -- I thought the battery in the fob was going, and replaced it, but still had problems. One night I went out to the car and touched the door handle and nothing happened, so I fished the iPod out of my pocket so I could retrieve the key fob and as soon as I took out the iPod the car dome light turned on. Voila! So now I keep the iPod in a different pocket and have had no more problems with the key fob.
     
    #6 priusman88, Jul 14, 2005
(You must log in or sign up to post here.)