Conclusion

In this guide, we introduced the concept of capacitive sensing. Nearly all sensing of this kind depends upon how long it takes a capacitor to charge (known as the time constant). Placing an object within the electric field of a capacitor will affect the capacitance value and the corresponding time constant. See the RC time constant entry on Wikipedia for more information.

We hope you appreciate the cleverness of this project as much as we did and how relatively easy it is to get a very 21st century interface (however crude) out of some aluminum foil and a cardboard box! We'd love to hear of your experiences with the build (in the comment section below).