I built this project because I kept forgetting to rest
The device
Before everything
The unusual part
How it works
Debugging became visual
What surprised me most

Published May 13, 2026 © GPL3+

My Tiny Pomodoro Goblin

I built a tiny Pomodoro device that kept asking me to rest, without knowing how to code.

BeginnerFull instructions provided2 hours144

Things used in this project

Hardware components

Seeed Studio XIAO ESP32S3

Seeed Studio Round Display for XIAO

Software apps and online services

Arduino IDE

Hand tools and fabrication machines

3D Printer (generic)

Story

I built this project because I kept forgetting to rest.

Not in a “burnout culture” kind of way. Just the very ordinary modern-human problem of staring at a screen for way too long until my eyes started hurting and my shoulders felt like concrete.

So I made a tiny thing that interrupts me.

The original inspiration was the Pomodoro Technique. I liked the idea of working in focused periods and taking intentional breaks, but also want a tiny desk companion that gently reminds me to drink water, rest my eyes, and maybe blink for a second.

1 / 3

I know I probably should’ve designed the enclosure and UI around an actual tomato. But somewhere along the process, I became more interested in making it feel calm rather than playful. Not with productivity guilt, but just with a quiet reminder.

The device

The hardware itself is tiny. Built with Seeed Studio XIAO ESP32S3 + Round Display for XIAO, this became a tiny desk companion that sits beside my keyboard and politely tells me to stop being a goblin.

The entire build is surprisingly mall. The round display ended up becoming the entire personality of the project. (The circle made it feel softer somehow)

Before everything

Firstly I followed the official getting-started guide of Seeed Studio for the round display to install the environment and the libraries as required:

The two wiki are very helpful and easy to follow, walking through Arduino IDE setup, board support, and adding the libraries that talk to the display driver and graphics layer.

Necessary libraries (Links below)

https://github.com/Seeed-Studio/Seeed_Arduino_RoundDisplay
https://github.com/Seeed-Studio/Seeed_GFX
https://github.com/limengdu/Seeed-Studio-XIAO-Round-Display-lvgl8.3.5/tree/main
Need to search and install the RTC library in the Arduino Library Manager.

The unusual part

With the necessary environment being set up, I then tried to design the UI for the 240×240 round screen, fitting timers, buttons, icons, titles and readable typography.

I should probably mention this: I did not know embedded systems before this project. No firmware background. No ESP32 experience. No real understanding of Arduino development. Honestly, barely any understanding of the code itself when I started.

Most of this project was created through a weirdly conversational process with ChatGPT:

describing behaviors in plain English
testing outputs
fixing visual bugs
repeatedly asking: “why is the tree disappearing?”

In some ways, this became my first experience with “vibe coding” hardware.

How it works

The device has four states:

Working: Focus timer runs one hour. You’ll see a circular progress indicator and the remaining time until break.
Reminder: After the focus interval finishes, the reminder screen appears. You have three choices: Start Breaks — begins a 2-minute rest session; Skip — returns to focus mode and resets the work timer; Snooze — delays the reminder for 5 minutes.

Debugging became visual

Because I wasn’t writing firmware traditionally, debugging became strangely design-oriented.

One problem was that a tree icon kept disappearing during the break screen. Then there was the "flicker." Every time the timer updated, the whole screen would flash like a dying lightbulb. It was the opposite of "restful." I had to figure out how to tell the code: Don't redraw everything, just change the numbers.

Most of my debugging process involved describing visual problems in plain English and then iterating with AI until the interface behaved correctly.

After this, I looked for enclosure ideas and eventually found a publicly shared 3D model that fit the XIAO and the Round Display well. (Special thanks to Koogar)!

What surprised me most

This project is small. It’s just a tiny round screen reminding me to blink, but it changed how I think about building things. A few months ago, I would’ve assumed hardware was inaccessible without years of technical experience.

Now I think the barrier has changed. Increasingly, you don’t necessarily need to begin with traditional engineering knowledge to start making interactive objects, which is both exciting and slightly surreal.

Anyway.

The tree finally works now.

Tiny Rest Reminder based on Seeed Studio XIAO EPS32S3

/*
  XIAO ESP32S3 + Seeed Studio Round Display
  Focus / Break Reminder

  Features:
  - Reminds user to rest after 1 hour
  - Break duration: 2 minutes
  - Buttons:
      Skip
      Remind in 5 min
      Start Break
  - Simple circular UI
  - Wellness icons:
      Water
      Tree
      Eye

  Libraries required:
  - TFT_eSPI
  - Seeed_Arduino_RoundDisplay

  Recommended:
  Install "Seeed Arduino Round Display" from Library Manager

  Board:
  Seeed XIAO ESP32S3

  Display:
  240x240 round LCD
*/

#include <TFT_eSPI.h>
#include <SPI.h>

TFT_eSPI tft = TFT_eSPI();

#define SCREEN_W 240
#define SCREEN_H 240
#define CENTER_X 120
#define CENTER_Y 120

// ---------- Timing ----------
const unsigned long WORK_INTERVAL = 60UL * 60UL * 1000UL;   // 1 hour
const unsigned long BREAK_INTERVAL = 2UL * 60UL * 1000UL;   // 2 minutes
const unsigned long SNOOZE_INTERVAL = 5UL * 60UL * 1000UL;  // 5 minutes

unsigned long sessionStart = 0;
unsigned long breakStart = 0;
unsigned long snoozeStart = 0;

// ---------- States ----------
enum AppState {
  WORKING,
  REMINDER,
  BREAKING,
  SNOOZE
};

AppState currentState = WORKING;
AppState lastState = WORKING;

// ---------- Touch Areas ----------
struct ButtonArea {
  int x;
  int y;
  int w;
  int h;
};

ButtonArea btnStart  = {60, 155, 120, 28};
ButtonArea btnSkip   = {40, 195, 70, 25};
ButtonArea btnSnooze = {130, 195, 70, 25};

// ---------- Helpers ----------
bool inButton(int tx, int ty, ButtonArea b) {
  return (tx > b.x &&
          tx < b.x + b.w &&
          ty > b.y &&
          ty < b.y + b.h);
}

// ---------- Drawing ----------
void drawRoundBackground() {
  tft.fillScreen(TFT_BLACK);

  // soft center circle
  tft.fillCircle(CENTER_X, CENTER_Y, 110, TFT_DARKGREEN);
  tft.fillCircle(CENTER_X, CENTER_Y, 100, TFT_BLACK);
}

void drawTitle(String text) {
  tft.setTextDatum(MC_DATUM);
  tft.setTextColor(TFT_WHITE, TFT_BLACK);

  // 长标题自动缩小
  if (text.length() > 14) {
    tft.setTextSize(1);
  } else {
    tft.setTextSize(2);
  }

  tft.drawString(text, CENTER_X, 40);
}

void drawSubtitle(String text) {
  tft.setTextDatum(MC_DATUM);
  tft.setTextColor(TFT_LIGHTGREY, TFT_BLACK);
  tft.setTextSize(1);

  tft.drawString(text, CENTER_X, 65);
}

// ---------- Wellness Icons ----------
void drawWaterIcon(int x, int y) {
  tft.drawRoundRect(x - 12, y - 16, 24, 32, 4, TFT_CYAN);
  tft.fillRect(x - 10, y, 20, 12, TFT_CYAN);
}

void drawTreeIcon(int x, int y) {
  tft.fillCircle(x, y - 10, 12, TFT_GREEN);
  tft.fillRect(x - 3, y, 6, 18, TFT_BROWN);
}

void drawEyeIcon(int x, int y) {
  tft.drawEllipse(x, y, 20, 10, TFT_WHITE);
  tft.fillCircle(x, y, 4, TFT_BLUE);
}

void drawWellnessIcons() {
  drawWaterIcon(60, 110);
  drawTreeIcon(120, 120);
  drawEyeIcon(180, 110);

  tft.setTextColor(TFT_WHITE, TFT_BLACK);
  tft.setTextSize(1);

  tft.setTextDatum(MC_DATUM);

  tft.drawString("Drink", 60, 150);
  tft.drawString("Nature", 120, 150);
  tft.drawString("Eyes", 180, 150);
}

// ---------- Buttons ----------
void drawButton(ButtonArea b, String label, uint16_t color) {
  tft.fillRoundRect(b.x, b.y, b.w, b.h, 8, color);

  tft.setTextColor(TFT_BLACK);
  tft.setTextDatum(MC_DATUM);
  tft.setTextSize(1);

  tft.drawString(label, b.x + b.w / 2, b.y + b.h / 2);
}

void drawWorkingScreen() {
  drawRoundBackground();

  drawTitle("Focus Mode");

  unsigned long elapsed = millis() - sessionStart;
  int progress = map(elapsed, 0, WORK_INTERVAL, 0, 360);

  // progress ring
  tft.drawCircle(CENTER_X, CENTER_Y, 70, TFT_DARKGREY);

  for (int i = 0; i < progress; i += 4) {
    float rad = (i - 90) * DEG_TO_RAD;

    int x = CENTER_X + cos(rad) * 70;
    int y = CENTER_Y + sin(rad) * 70;

    tft.fillCircle(x, y, 3, TFT_GREEN);
  }

  updateWorkingTime();

  tft.setTextSize(1);
  tft.setTextDatum(MC_DATUM);
  tft.setTextColor(TFT_WHITE, TFT_BLACK);

  tft.drawString("until break", CENTER_X, CENTER_Y + 30);
}

void drawReminderScreen() {
  drawRoundBackground();

  drawTitle("Time for a break");
  drawSubtitle("2 min reset");

  drawWellnessIcons();

  drawButton(btnStart, "Start Break", TFT_GREEN);
  drawButton(btnSkip, "Skip", TFT_ORANGE);
  drawButton(btnSnooze, "Snooze", TFT_CYAN);
}

void updateWorkingTime() {

  unsigned long elapsed = millis() - sessionStart;
  unsigned long remain = (WORK_INTERVAL - elapsed) / 1000UL;

  int mins = remain / 60;
  int secs = remain % 60;

  char buf[16];
  sprintf(buf, "%02d:%02d", mins, secs);

  // 只清中间数字区域
  tft.fillRect(90, 110, 60, 30, TFT_BLACK);

  tft.setTextColor(TFT_WHITE, TFT_BLACK);
  tft.setTextSize(3);
  tft.setTextDatum(MC_DATUM);

  tft.drawString(buf, CENTER_X, CENTER_Y);
}

void updateBreakTime() {

  unsigned long elapsed = millis() - breakStart;
  unsigned long remain = (BREAK_INTERVAL - elapsed) / 1000UL;

  int mins = remain / 60;
  int secs = remain % 60;

  char buf[16];
  sprintf(buf, "%01d:%02d", mins, secs);

  // ✅ 只清“数字本体区域”，不要碰背景/UI
  tft.fillRect(CENTER_X - 40, CENTER_Y - 70, 80, 40, TFT_BLACK);

  tft.setTextColor(TFT_WHITE, TFT_BLACK);
  tft.setTextSize(3);
  tft.setTextDatum(MC_DATUM);

    // 👉 放中间偏上，避开 tree
  tft.drawString(buf, CENTER_X, CENTER_Y - 50);
}

void drawBreakScreen() {

  drawRoundBackground();
  drawTitle("Relax");

  drawWellnessIcons();

  // 👉 关键：先画静态，再画动态
  updateBreakTime();
}

void drawSnoozeScreen() {
  drawRoundBackground();

  tft.setTextDatum(MC_DATUM);
  tft.setTextColor(TFT_WHITE, TFT_BLACK);
  tft.setTextSize(2);
  tft.drawString("Reminder Delayed", CENTER_X, 60);

  tft.setTextColor(TFT_CYAN);
  tft.setTextSize(2);
  tft.setTextDatum(MC_DATUM);
  
  tft.drawString("See you in 5 min", CENTER_X, CENTER_Y);
}

// ---------- Touch ----------
void handleTouch() {
  int32_t x, y;

  if (tft.getTouch(&x, &y)) {

    if (currentState == REMINDER) {

      if (inButton(x, y, btnStart)) {
        currentState = BREAKING;
        breakStart = millis();
      }

      else if (inButton(x, y, btnSkip)) {
        currentState = WORKING;
        sessionStart = millis();
      }

      else if (inButton(x, y, btnSnooze)) {
        currentState = SNOOZE;
        snoozeStart = millis();
      }
    }

    delay(250);
  }
}

// ---------- Setup ----------
void setup() {
  Serial.begin(115200);

  tft.init();
  tft.setRotation(0);

  sessionStart = millis();

  drawWorkingScreen();
}

// ---------- Loop ----------
void loop() {

  handleTouch();

  // 只有状态切换时才重绘整页
if (currentState != lastState) {

  switch (currentState) {

    case WORKING:
      drawWorkingScreen();
      break;

    case REMINDER:
      drawReminderScreen();
      break;

    case BREAKING:
      drawBreakScreen();
      break;

    case SNOOZE:
      drawSnoozeScreen();
      break;
  }

  lastState = currentState;
}
  // 工作状态计时
  if (currentState == WORKING) {

    static unsigned long lastUpdate = 0;

    if (millis() - lastUpdate >= 1000) {
      lastUpdate = millis();
      updateWorkingTime();
    }

    if (millis() - sessionStart >= WORK_INTERVAL) {
      currentState = REMINDER;
    }
  }

  // 休息状态计时
  if (currentState == BREAKING) {

    static unsigned long lastBreakUpdate = 0;

    if (millis() - lastBreakUpdate >= 1000) {
      lastBreakUpdate = millis();
      updateBreakTime();
    }

    if (millis() - breakStart >= BREAK_INTERVAL) {
      currentState = WORKING;
      sessionStart = millis();
    }
  }

  // snooze
  if (currentState == SNOOZE) {

    if (millis() - snoozeStart >= SNOOZE_INTERVAL) {
      currentState = REMINDER;
    }
  }

  delay(50);
}

Credits

Ellie Cai

1 project • 2 followers

My Tiny Pomodoro Goblin