RF Wakeup - RFID without the ID

Discussion in 'Wireless & RF Design' started by timpa04, Jul 6, 2014.

  1. timpa04

    Thread Starter New Member

    Jul 3, 2014
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    0
    I'm creating a "keyless" entry system using an nRF24L01+ and an AVR on both sides.
    The base units power consumption isn't a concern, however the keys power consumption is.

    The key will be powered by a CR2032 battery, and I would like to have an average consumption <14 µA.
    I've played around with duty cycles, but I can't get the consumption low enough since every message takes about
    25 ms from wakeup until the message bounces back.

    The only solution I can think of is having another RF module attached which would handle nothing but wakeup.
    It would be perfect if there is something like a passive receiver with a range of 1m-3m which would send an IRQ
    when it receives a signal.

    Do you have any suggestions?
     
  2. MrChips

    Moderator

    Oct 2, 2009
    12,446
    3,362
    Why would the power consumption of the key be a problem?

    The button on the key is the power switch. Hence the key consumes no power when not being used. If your button is a soft power-on switch, the MCU should be placed into low-power mode for lowest power drain.
     
  3. timpa04

    Thread Starter New Member

    Jul 3, 2014
    4
    0
    There won't be any button to push on the key, it's supposed to be what they
    call a keyless system. It will react simply by approaching.
     
  4. MrChips

    Moderator

    Oct 2, 2009
    12,446
    3,362
    Why make life complicated? Put a button on the key.
     
  5. timpa04

    Thread Starter New Member

    Jul 3, 2014
    4
    0
    Great answer. Thank you so much for your help
     
  6. timpa04

    Thread Starter New Member

    Jul 3, 2014
    4
    0
    Anyone else?
     
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