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I want to wear something so that a door will only unlock when i'm near it. Any ideas? Answered

I want to be able to wear a bracelet or similar thing with a transmitter so that when I come near doors in my home, they unlock for me.  I thought RFID but it sounds like they are expensive.  Any ideas?


Go to target or walmart and buy one of those cheap $20 USD metal dectors and make some sort of lock that unlocks then a couple volts of electricity goes through it and hook that up to the door with the volts coming throught where the LED is on the metal dector and all you have to do is put some metal to a part that you put the metal dector

Another solution: Set up a camera with pattern-recognition software (one of the 2D barcode decoders, perhaps) and wear a pin carrying the "password" where the camera can see it.

Proximitiy ("prox") card sensors are available with ranges of multiple feet. Just have the card in your wallet and walk up to the door. May be cheaper than RFID.

A much cheaper and simpler way to design a system like this would be to use a hidden magnetic reed switch ( http://www.hobbylinc.com/htm/bra/bra3530.htm?source=froogle ) The circuit could be really simple but obviously security is an issue with this system which is why I said a hidden magnetic reed switch and you could wear a small ring with a magnet on it to open the door. Anyway it's simple and cheap but it's not too secure.

The only <a href="http://cgi.ebay.com/40-GUMBALL-ARCADE-ECT-COLLECTABLES-AND-CHARMS_W0QQitemZ360195453131QQcmdZViewItemQQptZLH_DefaultDomain_0?hash=item53dd5270cb">KEY</a>.<br />

RFID is probably the best way to go, as mentioned by kelseymh. RFID is currently used for many applications similar to this, such as shutting off a car engine if the driver exits the vehicle, or even unlocking a door to let your pet in.

RFID.  You could build a solenoid lock and use an RF (carkey or X-10) clicker to drive it.

Of course, if you just have your significant other stay near the door of interest, wearing nothing ought to do the trick.