Discovering sensors

Sensors convert external readings into electrical signals. There are so many sensors that it would be impossible to list them all here. You can find sensors in three different implementations:

• On-board sensors: These come integrated with the microcontroller development board. MKR boards don’t come with those, but other Arduino Pro boards do.
• Breakout boards: These provide an interface such as a single pin, UART, SPI, or I2C for connecting to and communicating with a microcontroller.
• Shields: These are boards that are meant to attach to the top or bottom of a microcontroller and either integrate sensors or provide interfaces for connecting breakouts. We will discuss shields in the next chapter.

Let’s discuss some sensor categories.

Motion sensors

Motion sensors try to answer one or more of the following questions:

• Is this item in motion?
• What direction is this item headed in?
• Is this item being held upward...