Re: Automated front door lock?

[Marc F Hult <MFHult@xxxxxxxxxxxxxxxxxxxxx>]

On Wed, 3 Aug 2005 16:52:29 -0400, "Robert Green"
<ROBERT_GREEN1963@xxxxxxxxx> wrote in message
<nYSdnbJlxNAMs2zfRVn-1Q@xxxxxxx>:

>"Marc F Hult" <MFHult@xxxxxxxxxxxxxxxxxxxxx> wrote in message
>
>>> it would be great if one had a proximity sensor (RFID key fob or
>>> something) where the door would automatically unlock if I got
>>> within, say, 3-5 feet of it. That way I  could be carrying an
>>> armload of groceries and not have to fumble for my keys.
>> >
>> >Where should I be looking for this, if such an animal even exists?
>>
>> With even only a conventional security system, it is near-trivial to
>> add a secure, rolling code key fob so you can disarm the house,
>> open the garage door, unlock the front door with a single button
>> from 100 feet away and even have a panic button on the same fob
>> in case there is a situation that alarms you.
>
>Without delving into the relative merits of any of the proposed solutions,
I
>have to point out that fumbling with a key fob is often only slightly less
>irritating as fumbling with a keychain.

Agreed. My key fobs are usually in a drawer in the basement. My key chain
consists in three flat keys with the heads mostly ground off because I
travel light ...

But since the OP was talking about a bag of groceries (not a cab ride from a
security checkpoint), and the range of key fobs is on the order of 100 feet,
there is no fumbling involved  if one presses the button when one takes the
keys out of a car ignition.

>Probably the best way for me to accomplish hands-free unlocking would be to
>put a G-force sensor on the dog's tail, which wags furiously enough to
>clear end tables when she recognizes a family member at the front door.
>She does this through what I can only assume is a complex analysis of sound
patterns
>and perhaps smells.  She certainly can't see us - there's no access to a
>window for her - but she *knows* it's us.  If only my security system were
>so smart.

You joke (I think ? ;-), but sabres used in competitive fencing for about
the last decade use an accelerometer that signals the deceleration of the
blade when it strikes the opponent.  Recently, wireless has been introduced,
so there may be an off-the-shelf solution to signal when a dog's tail hits
the table  ;-)

Marc
Marc_F_Hult