New to RF and need help finding suitable modules

Discussion in 'Wireless & RF Design' started by mrjbones, Apr 25, 2011.

  1. mrjbones

    Thread Starter New Member

    Mar 26, 2011
    Hi all,

    I need a pair of modules (rx/tx) for a small personal project. The following are my constraints...

    1) Range: Should be reliable outside in the open at 300 feet.
    2) Transmitter must be small. Preferably small enough to fit in a key fob.
    3) Receiver should also be small but there is a little more wiggle room.
    4) I'd prefer the receiver had an integrated antenna. No room for a long one at any rate.
    5) Multiple rx/tx pairs may need to operate in the same area. It doesn't have to be secure or anything; transmitting a 4 or 8 bit ID (set with dip switches on both the rx/tx, maybe) would probably suffice.
    6) Other than #5, the data that needs to be transmitted is very simple. I need to send a single pulse on any one of three channels at a time. Or any equivalent that will work (e.g. 2 bits serially.)
    7) I need to interface with a PICAXE 08M on the receiver side.
    8) I don't care much about frequency except that I need to abide by US laws and need a short antenna.
    9) I'll need to build a bunch of these eventually so the lower the cost, the better. Ideally, price for each module would be less than $10 (i.e. less than $20 for a rx/tx pair.)

    Thanks for any recommendations, advice, pointers, or assistance of any kind that you can provide.

    Kind regards,
  2. mrjbones

    Thread Starter New Member

    Mar 26, 2011
    No help for the newb?
  3. bertus


    Apr 5, 2008

    Did you have a look at the xBee?
    They seem to reach 100 feet indoor and 300 feet outdoors.
    This PDF uses it in combination with a picaxe:

  4. radiohead

    Senior Member

    May 28, 2009
  5. mrjbones

    Thread Starter New Member

    Mar 26, 2011
    Bertus - Thanks. I think the xBee is probably overkill from the looks of it. I don't need a transceiver, for starters. Also looks a little larger than I'd like and a little more costly too. Definitely something good to know about for possible future projects though.

    radiohead - Thanks for that link. Something there should do the trick.