Every day, millions of people around the world use indoor temperature controls in the form of air conditioners and heaters. Additionally, some computing machinery and medical supplies must be stored at specific temperatures to remain optimal. To get an idea of how these systems function, we decided to build a small environment and attempt to keep it at a certain temperature.
Our temperature-controlled environment is a box roughly 200 cubic inches in size, and is made of poplar wood. On each side of the box is an opening, one for a hair dryer and one for a small fan. The fan draws air into the enclosure from a separate wooden box of similar size that contains a series of ice packs. Inside of the enclosure is an A3BU micro controller, which has a built-in temperature sensor, as well as a breadboard with an exposed LED and other necessary wiring. The hair dryer is plugged in to an “off” outlet of a controllable power relay that can be manipulated by the code on our A3BU. The fan receives its power directly from VCC of the A3BU.
The code that is loaded onto the A3BU controls which outlet on the power relay is activated. If the temperature in the enclosure is warmer than desired, the fan is activated and cold air blows in. If the temperature is cooler than desired, the off outlet relay is switched on, and the hair dryer is activated. Otherwise, if the temperature is as desired, both outlets are turned off. This keeps the control room at a relatively consistent temperature. By doing this project, we gained a basic understanding of the temperature-controlled systems found around the world.