This is a great lesson on how to get a simple touch sensor into your projects. This video appears to be one of a series of class visuals, and you can find several others on youtube under this account.

Study sensor signal noise and apply proper hardware techniques to reduce it to acceptable levels. In module 1 you will learn how to specify and use temperature sensors in an embedded circuit. First, ...

The sensor also detects liquid water with similar ease, either in the form of pooled liquid, or filled bottles. We’ve also seen a spring elegantly used as a hidden touch sensor that works ...