If you're tired of forgetting your house keys or garage door opener, Instructables user nodcah shows you how you can make your finger the only thing you need to access your abode.
The build requires some soldering, wiring, uploading code to an Arduino, and circuit board construction, but the end result sure is impressive. His case for the whole setup is 3D printed and offers the plans for download. Of course, if you don't have a 3D printer, you could probably find another creative way to house it all. He also points out that this setup isn't restricted to garage doors either, and you can create different motorised locks to be used with it.
It's a complicated project, sure, but it's way cooler than a hide-a-key! For a list of all the parts you need and a comprehensive guide to putting this bad boy together, check out the link below.