ATTiny Focus Timer

A minimal, distraction-free focus timer built around the ATtiny1614 microcontroller. Press a button, pick a duration, and get back to work - 10 WS2812B LEDs show your progress as a filling bar, then gently pulse and beep when time is up.

Created by @marius.builds

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How It Works

The timer cycles through four states:

State	LEDs	Sound
Idle	All LEDs glow white at low brightness	—
Running	Green progress bar fills one LED at a time	—
Completed	All LEDs pulse green (20 s grace period)	Finish melody (bee-beep-bee-beep)
Alerting	All LEDs pulse red	Short beep every 2 seconds

Buttons:

• In Idle — each of the 4 buttons starts a preset timer (10 / 20 / 30 / 60 min).
• In Running — any button cancels and resets.
• In Completed or Alerting — any button acknowledges and returns to Idle.

Hardware

Component	Qty	Notes
ATtiny1614	1	Programmed via megaTinyCore + UPDI
WS2812B / NeoPixel LEDs	10	Directly driven from PA3
Tactile push buttons	4	Connected to PB0–PB3, using internal pull-ups
Passive piezo buzzer	1	Driven from PA6 via tone()

Pin Mapping

PA3  →  NeoPixel data
PA6  →  Piezo buzzer
PB0  →  Button 1  (10 min)
PB1  →  Button 2  (20 min)
PB2  →  Button 3  (30 min)
PB3  →  Button 4  (60 min)

Software

Dependencies

• megaTinyCore — Arduino core for modern tinyAVR (ATtiny x04/x14/x24 series)
• tinyNeoPixel_Static — included with megaTinyCore; lightweight NeoPixel driver for tinyAVR

Building & Flashing

1. Install megaTinyCore via the Arduino IDE Boards Manager.
2. Select ATtiny1614 as the target board.
3. Set the programmer to CH340 UPDI (or whichever UPDI method you use).
4. Open ATTiny-FocusTimer-V2_1.ino and upload.

Configuration

All tunable parameters live at the top of the sketch — no need to dig through logic:

// Timer durations (minutes)
TIMER_1_MINUTES  = 10;
TIMER_2_MINUTES  = 20;
TIMER_3_MINUTES  = 30;
TIMER_4_MINUTES  = 60;

// Behavior
GRACE_MS         = 20000;   // completed → alerting delay (ms)
BEEP_EVERY_MS    = 2000;    // alert beep interval (ms)

// LED brightness (0–255)
IDLE_BRIGHTNESS  = 20;
RUN_BRIGHTNESS   = 120;
PULSE_MIN        = 30;
PULSE_MAX        = 160;

For quick bench testing, uncomment the shorter timer values (1 / 2 / 3 / 5 min) already provided in the sketch.

State Machine

         ┌──────────────────────────────────┐
         │           any button             │
         ▼                                  │
      ┌──────┐   button press   ┌─────────┐ │
      │ IDLE │ ───────────────▶│ RUNNING  │ │
      └──────┘                  └────┬────┘ │
         ▲                          │       │
         │ any button        timer done     │
         │                          │       │
    ┌────┴─────┐  grace timeout ┌───▼───────┤
    │ ALERTING │◀──────────────│ COMPLETED  │
    └──────────┘               └────────────┘

Enclosure

The project includes a 3D-printed case designed to house the PCB, LEDs, and buttons in a compact, desk-friendly form factor. The STL files are located in the case/ folder of this repository. They were designed for FDM printing with no supports needed. There are two types of top case formats. One of them is a one piece design (you have to keep in mind that in order for the LEDs light to go through you have to print the case in bright colors, ideally in white) and the other one that have a cutout for LEDs. The second one lets you print the case in any color because it have a LED COVER that you can print in transparent or any bright color. If you'd like to tweak the design, the original CAD is included as well (in .f3z format).

An external link for the case can also be found here : https://www.printables.com/model/1689049-attiny-focus-timer-case

PCB

Full fabrication files are provided in the pcb/ folder so you can order your own boards:

• Gerber files — ready to upload to JLCPCB, PCBWay, or any other fab house.
• BOM (Bill of Materials) — a spreadsheet listing every component with values, footprints, and reference designators.
• Schematic

License

This project is licensed under the MIT License. Feel free to use, modify, and share. Attribution appreciated.