Home >>  Electronics  >>  Design for an automated door locks(smart key less entry)

A situation occurs when we lock our car doors with key inside the car.For this a transmitter is attached to the keychain and a transponder inside the car.When we lock with key inside the car, the transponder activates the transmitter, which inturn will make a hand-shake signal back to the transponder.Thus the transponder knows that the key is with in the range of the car. There will be a mechanism which will automatically open the door. Please help me in doing this project sir.

  

This project can be done with bluetooth. Normal bluetooth devices have a max range of 10 mts. The keychain and the key can be bluetooth devices. Its very easy to know if a bluetooth device is in range. There are standard protocols for doing it. And if you are using bluetooth you dont have to fiddle with analog transmitters...

  

You can try buying a RF transciever with Signal Strength output feature. With this signal, the device will be able to estimate the range of the electronic key lock. http://www.siongboon.com/projects/2005-09-00_rf_transceiver www.siongboon.com email@siongboon.com