A kitchen timer reborn as a round ESP32 touchscreen

mircemkon Hackaday.io

Twist the ring, set the countdown, and watch the display change color as the time runs out. This ESP32-S3 timer is a classic kitchen timer with a 480x480 screen.

Build sheet

Display: 2.1in 480x480 round touch
Controller: ESP32-S3
Input: Rotary encoder ring
Output: Buzzer via PCF8574

Can I build this?Intermediate · AI 4/5 · $25–45

Difficulty: Intermediate
AI-buildability: 4/5
Time: A weekend
Cost: $25–45

Parts

CrowPanel Rotary Display 2.1in ESP32-S3 PCF8574 I2C I/O expander buzzer

Tools

soldering ironbreadboard

Starter prompt

Based on "A kitchen timer reborn as a round ESP32 touchscreen" on Afterware: https://afterware.xyz/p/a-kitchen-timer-reborn-as-a-round-esp32-touchscreen

Write ESP32-S3 firmware for a 480x480 round touchscreen with a rotary encoder ring, using LVGL or a similar UI library. Twist the encoder to set a countdown in minutes and seconds, change the arc color from green to red as the time runs low, and drive a buzzer through a PCF8574 I2C expander when the timer reaches zero.

Estimates based on the original write-up. How AI-buildability is scored. Building with an AI assistant? Connect it to Afterware (free MCP server).

Story

The heart of this build is a 2.1 inch CrowPanel "Rotary Display" that pairs an ESP32-S3 with a 480x480 round touchscreen and a rotary encoder built into the housing. The styling is meant to recall a Nest thermostat. Twist the ring and the on-screen graphics rotate to set the time, a bit like a high-tech version of the classic kitchen timer.

The board runs the maker's freely available code as-is. A PCF8574 I2C I/O expander drives a buzzer for audio feedback when the countdown hits zero, and the display changes color as time runs low, so you can read the remaining time from across the room.

Worth stealing: the hardware is essentially one off-the-shelf board, so the whole project is mostly firmware and a buzzer. If you already have a round ESP32 display, the input model here, a physical ring driving on-screen rotation, is a good template for any knob-driven interface.

Resources · 1

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