smallest possible bluetooh range

Archived from groups: alt.cellular.bluetooth (More info?)

Is it possible to limit bluetooh range to just a few centimeters?
I do not want to detect every phone in 10 meter radius but only those
that get very close(like 10 centimeters).

This would be very useful in such cases as mobile payment at a vending
machine: user just brings his phone closer to the vending machine, then
a "beep" sound is produced and a j2me application on the phone is
automatically activated (via push registry) which makes payment to the
vending machne - very similiar to those "Edy" RFID payments at japanese
POS terminals and subway gates:
http://web-japan.org/trends/business/bus041129.html

sergej panic
7 answers Last reply
More about smallest bluetooh range
  1. Archived from groups: alt.cellular.bluetooth (More info?)

    sergej.panic.xxx@gmail.com wrote:

    >
    > Is it possible to limit bluetooh range to just a few centimeters?
    > I do not want to detect every phone in 10 meter radius but only those
    > that get very close(like 10 centimeters).
    >
    > This would be very useful in such cases as mobile payment at a vending
    > machine: user just brings his phone closer to the vending machine, then
    > a "beep" sound is produced and a j2me application on the phone is
    > automatically activated (via push registry) which makes payment to the
    > vending machne - very similiar to those "Edy" RFID payments at japanese
    > POS terminals and subway gates:
    > http://web-japan.org/trends/business/bus041129.html

    That's not what Bluetooth was designed for. If you are making the vending
    machine then you might be able to do it by providing a shielded compartment
    into which the phone is inserted to extract payment.

    Personally it would be a cold day in Hell before I put my phone in such a
    device though.

    > sergej panic

    --
    --John
    to email, dial "usenet" and validate
    (was jclarke at eye bee em dot net)
  2. Archived from groups: alt.cellular.bluetooth (More info?)

    sergej wrote:
    > Is it possible to limit bluetooh range to just a few centimeters?
    > I do not want to detect every phone in 10 meter radius but only those

    > that get very close(like 10 centimeters).

    That's extremely impractical. The range of different phones varies a
    lot, for example, so you could find one phone that got 5 cm, another
    phone got 50cm, and so on. Also, the amount of noise caused by nearby
    devices - lights, other transmitters, and so on, will have a big impact
    on this.

    If you built a metal cage around the vending machine, and prospective
    customers walked inside of it, that might work... :)
  3. Archived from groups: alt.cellular.bluetooth (More info?)

    wrote on 03 apr 2005 in alt.cellular.bluetooth:

    > If you built a metal cage around the vending machine, and prospective
    > customers walked inside of it, that might work... :)
    >

    Such case would be inherently leaky for BT frequencies,
    otherwise it would be impossible to walk into.

    --
    Evertjan.
    The Netherlands.
    (Replace all crosses with dots in my emailaddress)
  4. Archived from groups: alt.cellular.bluetooth (More info?)

    Evertjan. wrote:

    > wrote on 03 apr 2005 in alt.cellular.bluetooth:
    >
    >> If you built a metal cage around the vending machine, and prospective
    >> customers walked inside of it, that might work... :)
    >>
    >
    > Such case would be inherently leaky for BT frequencies,
    > otherwise it would be impossible to walk into.

    Presumably there would be a door on it.


    --
    --John
    to email, dial "usenet" and validate
    (was jclarke at eye bee em dot net)
  5. Archived from groups: alt.cellular.bluetooth (More info?)

    > This would be very useful in such cases as mobile payment at a vending
    > machine: user just brings his phone closer to the vending machine

    This seems like a bad idea. For one, not enough phones will have Bt. Let
    alone have it configured PROPERLY for interacting with your service. The
    other is risk of fraud. You're far better off using SMS or another
    carrier-based service. That way you have a better "auditing trail" of
    whether or not the device is actually who it says it is. The messages have
    to go through the carrier and that provides a degree of accuracy/reliability
    to actually making sure it's the customer.
  6. Archived from groups: alt.cellular.bluetooth (More info?)

    J. Clarke wrote on 03 apr 2005 in alt.cellular.bluetooth:

    > Evertjan. wrote:
    >
    >> wrote on 03 apr 2005 in alt.cellular.bluetooth:
    >>
    >>> If you built a metal cage around the vending machine, and prospective
    >>> customers walked inside of it, that might work... :)
    >>>
    >>
    >> Such case would be inherently leaky for BT frequencies,
    >> otherwise it would be impossible to walk into.
    >
    > Presumably there would be a door on it.

    Presumed specs:

    ... no normal windows allowed, perhaps with special microwave proof glass in
    it, and microwave style door fittings with a system break off when the door
    is opened during the transaction including transaction roll back ...


    --
    Evertjan.
    The Netherlands.
    (Replace all crosses with dots in my emailaddress)
  7. Archived from groups: alt.cellular.bluetooth (More info?)

    Evertjan. wrote:

    > J. Clarke wrote on 03 apr 2005 in alt.cellular.bluetooth:
    >
    >> Evertjan. wrote:
    >>
    >>> wrote on 03 apr 2005 in alt.cellular.bluetooth:
    >>>
    >>>> If you built a metal cage around the vending machine, and prospective
    >>>> customers walked inside of it, that might work... :)
    >>>>
    >>>
    >>> Such case would be inherently leaky for BT frequencies,
    >>> otherwise it would be impossible to walk into.
    >>
    >> Presumably there would be a door on it.
    >
    > Presumed specs:
    >
    > .. no normal windows allowed, perhaps with special microwave proof glass
    > in it, and microwave style door fittings with a system break off when the
    > door is opened during the transaction including transaction roll back ...

    I believe I suggested earlier that rather than have a cage around the
    machine there be a compartment into which one inserts the cell phone, which
    I think would be much more workable. On the other hand, I'd rather just
    give the thing some of the spare quarters that I have weighing me down.

    --
    --John
    to email, dial "usenet" and validate
    (was jclarke at eye bee em dot net)
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