STEPPER

"My demonstration experimental device, known as the light pen, has been in use for nearly 10 years in physics classes. I felt it was time to refurbish this popular tool among my colleagues. The refurbishment primarily focused on the turntable that replaces the traditional record player. I replaced the DC motor used for control with an inexpensive (28BYJ-48 5V) stepper motor, whose speed can now be controlled via a mobile phone in the range of 0-20 revolutions per minute, thanks to the microcontroller built into the controller. The current speed can be read from the mobile phone display.

In the updated version, the turntable can also be powered by a battery, making it possible to place it anywhere in a classroom. The motor control and mobile phone connectivity are managed by an affordable LOLIN-LITE ESP32 microcontroller module."