Short Distance Communications (<10ft)

Discussion in 'Wireless & RF Design' started by danielb33, Dec 16, 2014.

  1. danielb33

    Thread Starter Member

    Aug 20, 2012
    Thanks for looking into my post. Note that RF is not my area of expertise.
    I am working on a project that requires two types of communication in one remote control - long range (>300 meters) for which I am using the ISM band, and short range (<10 ft)- which I am guessing I will use RFID @ 125KHz or similar.

    I do not want to go through FCC approval, so I am looking for pre-approved modules. I am using the Linx hummingbird series for long range.

    I have no clue what to use for the short range. RFID seemed appropriate but the readers are insanely expensive - each product would have to have a reader and a writer.

    The application will only need the short distance communication to work once a day or so and only needs to transfer a few bytes with low power.

    The remote will be used in all whether conditions.

    Am I missing anything? Does anybody have a recommended module or communication method to meet these needs? The key is short distance transfer with a module that costs < $15 at 1K volume/year. Knowing that GM, Ford, etc. use short distance communication in their cars (for instance, knowing when someone walks up to the car with the correct key) leads me to be confident that a cheap method of this short distance communication is available. The other key is that the short range must only transfer a maximum of 10 ft, but > 1 ft.

    I have looked into ANT, RFID, wireless sensors, IR (IR wont work due to line of sight requirement).

    Note: I understand all FCC approvals go out the window when two approved modules are used in the same device - but in this remote only one will need to be on at any given time, so approvals remain.
  2. alfacliff

    Well-Known Member

    Dec 13, 2013
    how about a 300 mhz module? or 439 mhz module? easily available, and range about right. like a garage door opener type.