XIAO ESP32-S3 Sense Retro Camera

A compact digital camera implementation using the Seeed Studio XIAO ESP32-S3 Sense development board and a 2.0" TFT LCD display (ST7789VW). Features high-resolution photo capture, AVI video recording with audio, and a live viewfinder with FreeRTOS multitasking for robust operation.

Features

• High-Resolution Photo Capture: Saves HD JPEG images (FRAMESIZE_HD: 1280×720) to the SD card.
• Video Recording: Records MJPEG video with PCM audio in AVI container format (FRAMESIZE_HVGA: 480×320, 7-10 FPS, 16 kHz mono audio via built-in PDM microphone).
• Live Viewfinder: Real-time camera feed (320×240 RGB565) displayed on the 2.0" TFT display with up to 320×216 pixel preview area.
• Hardware Mirroring: Toggle horizontal image mirroring using the built-in Boot button (selfie mode support).
• Robust Multitasking: Uses FreeRTOS dual-task architecture for concurrent camera feed processing, SD card monitoring, and real-time UI updates.
• Performance Monitoring: Live FPS counter and SD card status indicator on screen.
• Error Handling: Comprehensive error detection with on-screen notifications for camera failures, SD card issues, and write errors.
• PSRAM Optimization: Efficient use of ESP32-S3 PSRAM for frame buffering and AVI index storage.

Hardware Required

• Microcontroller: Seeed Studio XIAO ESP32-S3 Sense (with OV2640 camera & SD Card expansion board)
• Display: 2.0" TFT LCD Display Module (ST7789VW driver, 240×320 resolution, SPI interface)
• Buttons:
  • 1× Dual-leg shutter button (for photo/video control)
  • 1× Boot button on XIAO board (for image mirroring)
• Storage: MicroSD Card (FAT32 formatted)
• Power: 3.7V Li-ion battery or USB-C power (via XIAO board)
• Connecting Wires & Solder (for perfboard assembly)

Pin Configuration

TFT Display (ST7789VW) TFT Pin XIAO ESP32-S3 Pin GND GND VCC 3.3V SCL GPIO 7 SDA GPIO 9 RESET GPIO 3 DC GPIO 2 CS GPIO 1

Shutter Button & Control Button Function XIAO ESP32-S3 Pin Shutter Button 1 GPIO 4 (Output) Shutter Button 2 GPIO 5 (Input) Boot Button (Mirroring) GPIO 0 (Built-in)

Assembly & Battery Power

To create a portable retro camera, components are soldered onto a perfboard and powered by a 3.7V 18650 Li-ion battery.

Important Power Requirement: When the Seeed Studio XIAO ESP32-S3 is powered via the battery connector, the 5V output is disabled. Therefore, the TFT Display VCC and LED pins must be connected to the 3.3V pin instead of 5V to ensure proper operation on battery power.

Installation & Setup

PlatformIO Installation (Recommended)

1. Install Visual Studio Code with the PlatformIO extension
2. Clone/Open Project: Open the project folder in VS Code
3. Configure Board: PlatformIO automatically detects the seeed_xiao_esp32s3 board from platformio.ini
4. Configure Libraries: Required libraries are specified in platformio.ini:
   • lovyan03/LovyanGFX (Display driver)
   • espressif/esp32-camera (Camera support)
5. Build: Run PlatformIO: Build from the command palette
6. Upload: Connect XIAO ESP32-S3 via USB-C and run PlatformIO: Upload
7. Monitor: Open the serial monitor at 115200 baud to view debug output

Alternative: Arduino IDE Setup

1. Install Arduino IDE: Version 2.0 or later
2. Add Board Manager URL: In Settings, add:
   • https://raw.githubusercontent.com/espressif/arduino-esp32/gh-pages/package_esp32_index.json
3. Install ESP32 Package: Board Manager > Search "esp32" > Install "esp32 by Espressif Systems" (v3.x or later)
4. Select Board: Tools > Board > esp32 > "XIAO_ESP32S3"
5. Configure PSRAM: Tools > PSRAM > "OPI PSRAM"
6. Install LovyanGFX: Library Manager > Search "LovyanGFX" > Install latest version
7. Select Sketch: Open src/main.cpp (or copy to Arduino IDE as .ino)
8. Upload: Connect board and upload

Usage

Taking a Photo

• Action: Short press (< 1 second) the shutter button (GPIO 5)
• Process: Camera switches to HD mode (FRAMESIZE_HD), captures image, saves to SD card
• Display: Shows "HOLD ON..." dialog while saving; "PIC SAVED #X" confirmation after success
• Result: High-resolution JPEG saved as /hd_pic_N.jpg

Recording Video

• Action: Long press (> 1 second) the shutter button (GPIO 5)
• Process: Camera switches to video mode (FRAMESIZE_HVGA, 10 FPS), begins AVI encoding with audio capture from the built-in PDM microphone
• Display:
  • Clears screen and enters recording mode
  • Shows blinking red recording indicator (top-left)
  • Displays elapsed time in HH:MM:SS format (top-left)
  • Video preview scaled to fit screen
• Stop Recording: Press shutter button again (requires > 2 seconds of recording)
• Result: MJPEG video with PCM audio saved as /vid_N.avi
• Note: Recording pauses live preview; FPS counter shows actual recording frame rate

Image Mirroring

• Action: Press the small "Boot" button (GPIO 0) on the XIAO board
• Result: Camera feed horizontally flips (hardware mirroring)
• Use: Toggle between normal and selfie mode

SD Card Monitoring

• Automatic Monitoring: Dedicated FreeRTOS task monitors SD card status every 2 seconds
• Status Indicator: Green dot (bottom-right of screen) = SD ready; Red dot = card missing/full
• Recording Safety: If SD card is removed or becomes full during recording, recording automatically stops with warning message

Technical Details

Display & Camera Configuration

Setting	Live Preview	Photo Mode	Video Mode
Pixel Format	RGB565	JPEG	JPEG
Resolution	FRAMESIZE_QVGA (320×240)	FRAMESIZE_HD (1280×720)	FRAMESIZE_HVGA (480×320)
Display Area	320×216 pixels + 24px FPS bar	N/A	~240×160 scaled preview
JPEG Quality	0 (lossless RGB)	12 (high quality)	12 (high quality)

File System & Storage

• Photo Files: Sequential naming: /hd_pic_0.jpg, /hd_pic_1.jpg, etc.
• Video Files: Sequential naming: /vid_0.avi, /vid_1.avi, etc.
• Counter Persistence: Picture and video counters stored in EEPROM (survives power loss)

Video Encoding Details

• Format: MJPEG (Motion JPEG) video + PCM audio inside AVI container
• Video Resolution: 480×320 at 10 FPS (actual FPS auto-adjusted based on system load)
• Audio: 16 kHz, 16-bit, mono PCM via built-in PDM microphone
• Duration Support: PSRAM allocation supports ~36000 frames (~1 hour at 10 FPS)

Multitasking Architecture

• Task 1 (Core 0): SD Card Monitor

  • Priority: Low (1)
  • Stack: 4 KB
  • Duty: Monitor SD card status, free space, removal detection

• Task 2 (Core 1): Camera & UI

  • Priority: High (5)
  • Stack: 8 KB
  • Duty: Camera capture, screen rendering, button handling, photo/video save

• Synchronization: FreeRTOS mutexes protect concurrent SD card and display access

Interface & On-Screen Feedback

Startup Screen

• "GETTING READY" message with progress
• Indicates initialization of camera, display, and SD card
• Shows credit: "github@barkinsarikartal"

Live Viewfinder

• 320×216 pixel camera feed with RGB565 rendering
• Bottom status bar (24 pixels):
  • FPS counter (bottom-left, green text)
  • SD card status dot (bottom-right: green = ready, red = error)

Troubleshooting

Camera Not Initializing

• Check USB power supply (requires > 500 mA during capture)
• Verify GPIO pin connections to OV2640 camera module
• Check Serial output for "Cam init error" message

Display Shows Inverted Colors

• Edit src/main.cpp line with pcfg.invert = true/false
• Some ST7789VW modules differ in color polarity
• Test with pcfg.invert = false if colors appear inverted

Performance Notes

• Live FPS: Typically 15–25 FPS on 320×240 RGB565 (depends on how long the microcontroller has been running)
• Photo Capture: ~3–5 seconds total (mode switch + warm-up + save)
• Video Recording: 7–10 FPS achieved (limited by SD card write speed and JPEG encoding)

License

This project is licensed under the MIT License. See the LICENSE file for details.