EX: LED Temperature Display

Goals

• Learn how to use GPIO pins on Linux

• Learn how to abstract details away. Talk about boolean values, and not LEDs that emit light or not.

Hardware

• A number of LEDs, arranged linearly from left (cold) to right (hot)

• The usual sensors

Outcome

A program that

• … periodically queries the configured thermometers and builds the average. This is done by using one single averaging thermometer that does the query, internally.

• … feeds the computed average temperature into said LED display device.

  • That display device is abstracted into something that just displays temperatures (its users don’t want to have to know that it is implemented with seven LEDs).

• A number of unit tests