Keyfob Help

Discussion in 'Wireless & RF Design' started by Dlloyd86, Jul 6, 2011.

  1. Dlloyd86

    Thread Starter New Member

    Jul 6, 2011
    I stumbled upon this forum trying to find an answer to my question. The plastic casing on my car's key fob remote broke and I got the idea to practice my machining skills and fabricate a new housing for it out of metal. I found some scrap brass and was succesful in making said case. However, it came with some unintended side effects, namely where my remote once had decent range I now have to be literally two feet away from the car for the remote to work. I have made the case as thin as I can, but my theory is the metal case is blocking the RF signal. Is there anything I can do to improve the function of my remote? I can simply by a new plastic case granted, but I would really like to make the one I fabricated myself work. . .
  2. KJ6EAD

    Senior Member

    Apr 30, 2011
    You've inadvertently created a shielded enclosure. The antenna is mounted on the circuit board or is part of it. Get a plastic case.
  3. strantor

    AAC Fanatic!

    Oct 3, 2010
    Maybe encapsulate the board in clear potting, then sand it downto the keyfob shape. would look cool, you could see the PCB inside.

    You would would only get one shot at it.

    you would probably end up sticking your buttons down permanently.
    you would never get the battery out.

    if you could find a way around those two obstacles, it would be friggin sweet IMO,
  4. shortbus

    AAC Fanatic!

    Sep 30, 2009
    The o/p said he has machine access and skills, what about using Plexiglas/Perspex/Acrylic to make a case? After sanding smooth it can be made clear again with a flame from a propane torch. By using small screws to hold two halves together battery could be changed
  5. someonesdad

    Senior Member

    Jul 7, 2009
    You might try perforating it a bit, but it's still essentially a Faraday cage and the perforations will be much smaller than the wavelength. You might see some improvement, so it's worth a try as otherwise the metal case is not terribly useful unless you can somehow rig up an external antenna (probably not worth the effort).

    Shortbus, you're one of the few people I've ever seen who actually know how to properly spell Plexiglas. I remember making a gooey mass of it in my elementary chemistry lab in college (polymethyl methacrylate or PMMA).
  6. ErnieM

    AAC Fanatic!

    Apr 24, 2011
    How about just connecting the antenna to the very nice case you've already made?