Hovering a Ping-Pong Ball: A Demonstration Setup for Teaching PID Control

Proportional-Integral-Derivative (PID) controllers are
essential
in ensuring the stability and efficiency of numerous scientific, industrial,
and medical processes. However, teaching the principles of PID control
can be challenging, especially when the introduction focuses on the
underlying mathematical framework. To address this, we developed the
PingPongPID, a visually engaging and interactive demonstration instrument
designed to make the concepts of PID control more accessible to students.
The PingPongPID features a colored ping-pong ball suspended within
a transparent plastic tube by a fan, the voltage of which is controlled
by a microcontroller running a PID algorithm. The ball’s height
is measured in real-time by a laser distance sensor, and the system
continuously adjusts the fan voltage to maintain a set target height.
The PingPongPID also connects to a computer, allowing real-time data
logging and visualization through a custom-built Python graphical
user interface (GUI). The process of obtaining the three PID gain
constants using both the trial-and-error and Ziegler-Nichols methods
can be illustrated very nicely with the PingPongPID. In summary, the
PingPongPID serves as a powerful educational tool, allowing students
to explore both the conceptual and practical aspects of PID control
before delving into its mathematical foundations. We provide a complete
assembly and user guide for the PingPongPID as well as the codes for
the microcontroller and the Python GUI.