I started thinking that maybe I should cover some terms and definitions about sensing and measurement for this project before getting too deep into it.

First off, the words sensor and transducer are both widely used when referring to the measurement of physical phenomena and properties. Generally, the transducer is the component measuring the input energy or physical property, and the sensor contains the transducer as well as any circuitry required to convert the measurement into a usable electrical signal.

Here’s a small diagram of what makes up a sensor:


Let’s list out some of the different physical properties that we cold potentially measure:

1) Flow of liquids or gases
2) Levels of solid or liquid
3) Direction of flow for gases or liquids
4) Relative amount of liquid in a gas (humidity)
5) Amount of light striking a surface
6) Ph / Conductivity
7) Temperature
8) Acoustic (magnitude, spectrum)
9) Pressure / Strain / Force
10) Electrical (current, potential, and field properties)
11) Magnetic

Now I realize some of these do not seem extremely applicable to a home environment, but I would rather not limit myself just yet.

Next, we’ll list out some potential measurement possibilities around the household.