FlipClock

A minimal, flicker-free flip clock for ESP32-C3 + ST7789 LCD (240×320), with perspective-correct page-flip animation in 265 lines of C++.

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Preview

The flip animation uses trapezoidal strip distortion to simulate foreshortening in perspective. The upper half folds down, the lower half unfolds, and side thickness shading completes the classic mechanical flip-clock look.

Features

• 265-line minimal implementation — single main.cpp, no frameworks, no bloat
• Zero-float runtime — trig lookup tables (int8_t), pure integer animation
• Direct framebuffer blitting — memcpy over drawPixel(), 10× faster
• RGB565 pre-composited sprites — no alpha blending at runtime
• ~165 KB RAM saved — canvas only covers the visible 240×48 strip
• Flicker-free double buffering — full-frame GFXcanvas16 + single SPI transfer
• 20 FPS flip animation — perspective trapezoid strip deformation

Hardware

Component	Model
MCU	ESP32-C3 (esp32-c3-devkitm-1)
Display	ST7789, 240x320, SPI
Flash	DIO mode, 80 MHz

Wiring

Pin	GPIO
MOSI	3
SCLK	2
DC	4
RST	5
CS	7

Build & Flash

Requires PlatformIO.

pio run                    # build
pio run --target upload    # flash
pio device monitor         # serial monitor (115200)

Project Structure

src/
  main.cpp      # Entry point: SPI init, flip animation rendering, time keeping
  digitals.h    # 0-9 digit bitmaps as pre-composited RGB565 data (upper/lower halves, 32x24 each)
platformio.ini  # PlatformIO build configuration

Dependencies

• Arduino Framework (C++11)
• Adafruit GFX Library 1.12.6
• ST7789_AVR 1.2.3