Intro: Doctor Who Tardis Key Perception Filter
Step 1: Supplies
There are only three components to this project. A scrap key, an eight pin chip, and a ceramic capacitor. 555 timers a caps are common hobby project parts. These parts can be purchased new from places like Radio Shack and Diji-key, but can be found on scrap boards just as easily. These orange ceramic caps are more commonly found on older boards (as SMTs have widely replaced their Through-hole counterparts) while the chips are more common in newer ones. If you don't have a bin of dead keys, your local hardware store may have a bin of mis-cut keys from which you can choose.