First, I observed the door of my house, as the picture above.
As you can see, as long as the red part of the figure pulled in the direction of the arrow, the door can be unlocked, and of cause, when not pulled, the red part go back to it’s original location to lock the door. So I think, a servo would be OK to accomplish this function.
And, i need a fingerprint sensor, too, when i or my wife press the fingerprint sensor, which can determine whether a person is certified, it outputs instructions to the Arduino, to control servo to open the door.
I use the following modules:
，this is an Arduino compatible microcontroller boards, i use it because it is cheap enough, and has some upgrading on the design, such as the reset button on the side.
2. FingerPrint Sensor
3. A servo with enough torque
4. Glue，or anything that can be used to fix these modules
5. 5V USB power supply
or 9V DC jack power supply
6. Some jumper wires would be help.