Abstract:
Internet of Things (IoT) applications have become increasingly popular along
with the technology development of various sensing devices. In this study, a recursively
digital Proportional Integral Derivative (PID) algorithm has been applied to develop an
Arduino-based IOT thermostat sensor system. By deploying such a low-power device,
environmental temperatures are acquired and sent into an Arduino controller to make
comparisons with the target temperature variation. By using the Pulse Width Modulation (PWM) control principle, the recursive digital PID calculation is converted to drive
the PWM duty-cycle output current to achieve heating and cooling for the thermostat
condition. Noting that by using low-cost electronic components with the development of
the Arduino controller, PID operation and PWM technology, temperature tracking has
been demonstrated by controlling and adjusting a lamp bulb and an electric fan to achieve
a complete smart thermostat control. Additionally, the temperature data gathered in the
Arduino controller can be uploaded to a cloud database. By using an Android mobile
device, which is used as a display and control interface, temperature information can be
conveniently accessed, such as temperature curve exporting, real-time monitoring of past
temperature changes, and even further large-data analysis results in the cloud database.
