Here’s an interesting way to add a touch of security to your door in a DIY way. The Instructable for this Arduino Fingerprint Lock shows how a man added a fingerprint scanner to a door lock. Now he can run out of his home for a quick trip to the store and not have to worry about keys. He used the following parts in addition to the door lock to achieve this:
1. Crowduino，this is an Arduino compatible microcontroller board.
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.
It takes a bit of programming to get the fingerprints loaded into the Crowduino but overall it’s a pretty slick DIY home security project. Full step by step details at the link above.