In several of my previous videos, I presented different projects based on the CrowPanel 2.1-inch HMI ESP32 Rotary Display. This compact and very practical module combines a circular color touchscreen, an ESP32-S3 microcontroller, a rotary encoder with a push button, and an I2C connector for communicating with external devices. This combination of features makes it an ideal platform for my latest project — a Universal Timer with a clean, user-friendly interface and a very simple and intuitive way of setting the desired time. 

Detailed video description at: https://youtu.be/buSYu1Nq2f4

 The main idea was to create a timer that can be operated almost entirely with the rotary encoder. Turning the encoder sets the desired time, while a short press of the button starts, pauses, or resumes the countdown. A long press immediately resets the timer to zero. The circular display is used as a visual representation of the remaining time. The red area represents the selected or remaining time, while the white area gradually increases during the countdown. Thanks to framebuffer-based screen drawing, all graphic changes are smooth and free from unpleasant flickering. Four timer ranges are available: 1 minute, 10 minutes, 30 minutes, and 60 minutes. 

The range can be changed simply by touching the lower part of the display. Each range also has its own scale color: yellow for 1 minute, turquoise for 10 minutes, orange for 30 minutes, and magenta for 60 minutes. The scale automatically changes according to the selected range, making it easy to estimate the remaining time even without reading the numerical display. For additional indication, I connected an external PCF8574 I2C I/O expander and an active buzzer. 

 When the countdown reaches zero, the display flashes red three times while the buzzer produces three synchronized beeps. The result is a compact and practical timer that is very easy to operate and can be useful in the workshop, kitchen, laboratory, photography, electronics experiments, or anywhere else where a simple visual countdown timer is needed.

  A few recommendations regarding the installation of the code. 

 To avoid a black screen or unpleasant flashing, it is necessary to install ESP32 Core ver 2.0.17 on the Arduino, and the Arduino_GFX v1.6.1 library. On the ESP32 S3, the flash size should be set to 16MB, Partition Scheme - Huge APP, and PSRAM - OPI psram.

It can be noted that most of the parameters are defined at the beginning of the code, so various modifications can be made very easily, for example, changing the colors or geometry. As usual, the complete Arduino code and additional information about the project can be found in the description below the video.

  Now let's see how the device performs in real conditions.

 And finally a short conclusion. This project shows how the CrowPanel 2.1-inch ESP32-S3 display can be transformed into a compact, intuitive, and highly practical universal timer with both visual and audible indication.