LED Pomodoro Timer

A silent, highly visible Pomodoro timer built around an Arduino Mega-compatible board, a 30-LED layout, and a custom laser-cut enclosure designed in LightBurn.

This version was created to support focused work, concentration, and regular off-screen breaks without using sound. The device replaces audio alerts with large, conspicuous LEDs to mark a 25-minute focus block followed by a 5-minute break block.

Why this project exists

This build answered a specific request:

• no audible alerts
• very conspicuous LEDs for obvious visual timing cues
• 25-minute focus intervals with a 5-minute break
• regular desk-break reminders to reduce continuous screen exposure and support whole-body wellness
• a physical object that can sit on a desk and be understood at a glance

The focus phase is intentionally not as a constant countdown display. Each focus LED flashes only near the end of its minute, then turns back off. The timer stays mostly visually calm until the 25-minute block is complete. At that point, all 25 focus LEDs turn on together and stay on until the focus button is pressed again. The goal is to stay immersed in work, study, or concentration until the final “all 25 focus LEDs on” state becomes impossible to ignore.

What is in this repository

• the original Arduino sketch
• the original LightBurn enclosure source file
• the Fritzing wiring diagram
• prototype and finished-build photos
• repo-ready documentation for the firmware, electronics, enclosure, and build rationale

Project snapshot

• Platform: Arduino Mega 2560-compatible board
• LED count: 30 total
• LED layout: 25 focus LEDs + 5 break LEDs
• LED resistor count: 30 total, one 100Ω resistor per LED channel
• Controls: 2 momentary pushbuttons
• Interaction model: silent visual timer with separate work and break controls
• Power source: 1 × Power Bank 2200 USB power bank
• Enclosure: laser-cut 3 mm MDF enclosure with engraved tomato-face artwork
• Design source: LightBurn .lbrn2 file

Power

Normal portable use was through a Power Bank 2200 USB battery pack.

• Capacity: 2200 mAh
• Battery type: lithium-ion
• Rated input: DC 5V / 800 mA
• Rated output: DC 5V / 800 mA
• Charging time: about 3 hours
• Protection: built-in short-circuit, over-charge, and over-discharge protection

That power source was used successfully to run the device in normal portable use.

How the timer is laid out

• 25 focus LEDs arranged around the face of the timer
• Focus LED color pattern: four cool-white clear 10 mm LEDs followed by one green 10 mm LED, repeated across the 25-minute ring
• 5 break LEDs grouped on the upper-left arc of the face
• Break LED color: all red 10 mm LEDs
• 2 buttons: a large green focus button and a large red break button

Clock-face layout

The physical layout follows a fixed clock-face orientation:

• 1:00 o’clock position: the large green focus button
• 1:00 to 9:00 arc: the focus LED group
• 9:00 o’clock position: the large red break button
• 9:00 to 11:00 arc: the break LED group

How it works

Focus phase

• Press the focus button to start a 25-minute work block.
• One focus LED flashes after each 58-second interval and stays lit for 2 seconds.
• After the twenty-fifth interval, all 25 focus LEDs turn on and remain on.
• Press the focus button again to clear the focus LEDs.

Break phase

• Press the break button to start a 5-minute break block.
• One red break LED turns on after each 60-second interval.
• After 5 minutes, all 5 break LEDs are on.
• Press the break button again to clear the break LEDs.

Repository structure

firmware/                  Final Arduino sketch
hardware/lightburn/        LightBurn enclosure source
hardware/fritzing/         Fritzing wiring diagram
docs/img                   Prototype and finished-build photos
docs/                      Technical documentation

Quick start

1. Review the documentation hub at docs/README.md.
2. Open firmware/pomodoro-led-timer-final.ino in the Arduino IDE.
3. Review the pin map in docs/FIRMWARE.md before wiring.
4. Open hardware/lightburn/pomodoro-led-timer-enclosure.lbrn2 in LightBurn to inspect the enclosure geometry and cut plan.

Documentation

• Documentation hub
• Firmware
• Electronics
• Enclosure
• Build notes
• Bill of materials
• Source artifacts

Build photos

Documentation stance

This repo treats the final firmware, the LightBurn enclosure file, the Fritzing wiring diagram, and the build photos as the governing project artifacts.

Hardware documentation notes

The repo uses the Fritzing wiring diagram as the main wiring reference for the build. See docs/ELECTRONICS.md and hardware/fritzing/README.md.

License

This project is open source and available under the MIT License.