Simplest mobile/cell phone detector

Discussion in 'The Projects Forum' started by ecjohnny, Jul 9, 2012.

  1. ecjohnny

    Thread Starter Senior Member

    Jul 16, 2005
    Hey guys i got interested in building simplest mobile phone detector.
    I came across this little thing called "LED mobile flashing sticker" and i wonder what kind of circuit it uses. After some google, i still can't find the circuit diagram for it but i found out its theory.. if anyone know please let me know.

    Although i cannot find its circuit diagram, i found two similar project which work just like it. Here are the links:



    I am thinking of building one of these 2 to try out but i encountered some problem.

    For 1) Does anyone know if any kind of RF diode would work? because there is no 1N34A from my local online electronic store but it does sell a list of RF diode but i dunnoe which to choose from.

    For 2), it says n4148 diode, again there is a list of the diode from my local online electronic store that i dunnoe which to choose from. Some quite cheap but is there any attribute/type requirement that is needed for this circuit to work before i just buy the cheapest?

    Thanks for helping!:)
  2. absf

    Senior Member

    Dec 29, 2010
    I saw those RF stickers in phones accessories shop here, but I didn't buy any of them to play with.

    1N34A are germanium diodes and you're able to get them from eBay easily. They have lower forward voltage drop compared to silicon diodes. Probably you can replace them with schottky diodes.

    It probably is 1N4148. A common silicon signal diode.

    Last edited: Jul 9, 2012
  3. Dodgydave

    Distinguished Member

    Jun 22, 2012
    I would use an OA91 diode as that is an rf diode germanium as is the IN34A