Utilizing a ready made electronic deadbolt but with heavy modifications jeepdude48507 made an RFID operated one:
|"This is a fun an very useful project that allows easy access into any door with a deadbolt. I have another version that is used on my garage door and uses the same basic circuit and fobs. The system operates in the RF region at 125 KHz. Fobs are used to actuate one of two relays on the main control board. With each scan the deadbolt toggles - if it is unlocked it locks and the red LED comes on, if locked it unlocks and the green LED comes on. One relay causes the deadbolt motor / mechanism to lock the door, the other causes the door to unlock. A regular key can still be used and the deadbolt can still be locked and unlocked manually if desired. Operating the circuit with the key or manually operating it with the deadbolt knob can cause it to fall out of sync with the controller and indicate locked when it is actually unlocked or vice versa. To correct this just cycle the unit with the pushbutton on the deadbolt housing or flip the deadbolt knob the opposite way. I have thought about adding some limit switches to eliminate this problem. Perhaps in some future version I will implement them. I have been using this project for a couple of months with very few hiccups. It is fun to build and adds a definite 'nerdivity' to my home.|
I based the project on a store-bought electronic deadbolt. It was battery operated and had a keypad on the outside to allow entry with a user defined code. I removed all of the electronics from the indoor housing keeping only the electric motor and mechanism. The mechanism has a built-in clutch that prevents damage should the motor remain on for too long when cycling. My motor is set for a cycle time of about 1.25 seconds."