A open-source countdown timer built on a round touchscreen CrowPanel shows how a rotary dial can make setting time intuitive.
A maker known as mircemk has released a project called Universal Timer, built around the 2.1 inch CrowPanel Rotary Display. The device pairs an ESP32-S3 processor with a 480 by 480 round touch screen and a rotary encoder built into the housing. Its styling is meant to recall the Nest thermostat and similar commercial products, and the hardware works on its own with the supplied code.
For extra feedback, the design adds a PCF8574 I2C I/O expander that drives a buzzer, which sounds when the countdown ends. Setting a time is done by turning the ring around the display. The on-screen graphics rotate in step with the movement, giving the experience of a classic kitchen timer but with a modern interface.
The display also changes color as the remaining time shrinks toward zero, so users can judge how much time is left from across the room. The code is freely available for anyone who wants to run it or modify it.
The project is one of a growing number of efforts that reuse round displays, which have become cheaper as smartwatches have grown popular. Similar boards have also been used for desktop flight-tracking displays.
Source: Hackaday
