Dashcam

A dashcam firmware for the LILYGO T-CameraPlus-S3 development board. Records camera video and microphone audio into standard AVI files saved to a microSD card, with real-time preview on the LCD.

Hardware Requirements

Component	Specification
Board	LILYGO T-CameraPlus-S3 V1.2
MCU	ESP32-S3, 240 MHz, 16 MB Flash, 8 MB PSRAM
Display	240×240 ST7789V LCD
Camera	OV2640 / OV5640 (auto-detected)
Microphone	MP34DT05TR digital microphone (PDM)
Storage	microSD card (Class 10 / U3 recommended, 32 GB+)
PMU	SY6970 power management
Touch	CST816S touchscreen

Note: The pin definitions in board_pins.h correspond to V1.2. V1.0 / V1.1 have different SPI, I2C, camera, and microphone pins — refer to the actual board silkscreen to make adjustments.

Features

• Loop recording: Automatically records video as AVI files (Motion-JPEG video + 16-bit PCM mono audio), with each clip defaulting to 60 seconds, stored in the /dashcam directory on the SD card.
• Loop overwrite: Automatically deletes the oldest clips when free SD card space drops below 150 MB, ensuring uninterrupted recording.
• Live preview: The recording is displayed in real time on the 240×240 LCD with an overlaid status bar (recording duration, free space, battery level, frame rate).
• Photo snapshot: Touch the screen or press KEY2 to save a JPEG photo to the /photos directory on the SD card at any time.
• Auto-start: Recording begins automatically on power-up (can be disabled in config.h).
• Audio recording: I2S digital microphone simultaneously captures 16 kHz mono audio and mixes it into the AVI file.

Flash Firmware

ESP32 烧录工具 (官方API)

⚪未连接

选择固件

请选择固件Dashcam

操作日志

Operation

Action	Function
Power on	Recording starts automatically (AUTO_START_RECORDING=1)
Press KEY1 (GPIO 17)	Take a snapshot, saved to /photos, plays a confirmation tone
Press KEY2 (GPIO 0)	Toggle recording start / stop, plays a confirmation tone
Touch screen	Take a snapshot

LCD Status Overlay

Icon / Field	Meaning
REC red dot	Currently recording
00:01:23	Elapsed time of the current clip
1234 MB	Remaining SD card space
85%	Battery level
⚡	Charging
24 fps	Current recording frame rate

File Structure

SD card
├── dashcam/
│   ├── CLIP_0001.avi
│   ├── CLIP_0002.avi
│   └── ...
└── photos/
    ├── IMG_0001.jpg
    └── ...

Key Configuration

All recording parameters are centralised in config.h — no source code changes required:

Parameter	Default	Description
REC_SEGMENT_SECONDS	60	Clip duration (seconds)
REC_MIN_FREE_MB	150	Minimum free SD space; triggers loop deletion when exceeded
CAM_JPEG_QUALITY	14	JPEG quality (lower value = higher quality, larger file)
CAM_FRAMESIZE_OV2640	SVGA 800×600	OV2640 resolution, ~25 fps
CAM_FRAMESIZE_OV5640	HD 1280×720	OV5640 resolution, ~30 fps
AUDIO_ENABLE	1	Whether to record audio
AUDIO_SAMPLE_RATE	16000	Audio sample rate (Hz)
PREVIEW_EVERY_N_FRAMES	6	Update LCD preview every N frames
AUTO_START_RECORDING	1	Whether to start recording automatically on power-up

---

Build & Flash

PlatformIO (Recommended)

Requirements:

• VS Code + PlatformIO IDE extension
• Or PlatformIO Core CLI

Steps:

# 1. Enter the example directory
cd examples/Dashcam

# 2. Build
pio run

# 3. Flash (connect the board first)
pio run -t upload

# 4. Open serial monitor (115200 baud)
pio device monitor

# One-shot: build + flash + monitor
pio run -t upload && pio device monitor

After a successful build, the merge_bin.py post-processing script automatically merges the bootloader, partition table, and application firmware into a single flashable file:

firmware_out/T-CameraPlus-S3_Dashcam.bin

Flash the merged firmware directly (no build environment required):

esptool.py --chip esp32s3 --baud 921600 write_flash 0x0 firmware_out/T-CameraPlus-S3_Dashcam.bin

---

Arduino IDE

Requirements:

• Arduino IDE 2.x
• ESP32 Arduino core 2.0.14 (installation guide)

Install required libraries (search in Library Manager):

Library	Version
LovyanGFX	^1.1.16
JPEGDEC	^1.6.2
XPowersLib	^0.2.6
OneButton	^2.5.0

Board settings (Tools menu):

Option	Value
Board	ESP32S3 Dev Module
Flash Size	16MB (128Mb)
Partition Scheme	Custom (manually import partitions.csv)
PSRAM	OPI PSRAM
Flash Mode	QIO 80MHz
USB Mode	Hardware CDC and JTAG
CPU Frequency	240MHz (WiFi)
Upload Speed	921600

Steps:

1. Open Dashcam.ino.
2. Configure the board options as shown above.
3. Click Upload to build and flash.
4. Open the Serial Monitor and set the baud rate to 115200.

Tip: Arduino IDE does not support directly importing a custom partition table file. It is recommended to add the partition scheme from partitions.csv to the Arduino core's boards.txt in advance, or use PlatformIO to avoid partition configuration issues.

---

Architecture

The firmware uses FreeRTOS dual-core parallelism:

Task	Core	Priority	Responsibility
recordTask	Core 1	5	Camera capture, AVI muxing, SD write
uiTask	Core 0	3	LCD preview rendering, touch detection, button polling, PMU status
mic task (internal)	Core 0	—	I2S capture → FreeRTOS Stream Buffer

The LCD and microSD share the same SPI bus; a mutex (spibus::Guard) ensures safe concurrent access.

Unit Tests (AVI Writer, Host-only)

The AVI writer module can be tested independently without hardware:

g++ -std=c++14 -I../../src test/host/test_avi.cpp avi_writer.cpp -o test_avi
./test_avi

Troubleshooting

Recording does not start / LCD shows "NO SD CARD"

• Check that the SD card is inserted and formatted as FAT32 or exFAT.
• Recommended: 32 GB or larger, Class 10 / U3.

No audio

• Check that AUDIO_ENABLE is set to 1 in config.h.
• Check that AUDIO_I2S_CHANNEL matches the microphone channel on your board.

Low frame rate

• Increasing CAM_JPEG_QUALITY (higher numeric value) reduces file size and improves frame rate.
• Increasing PREVIEW_EVERY_N_FRAMES reduces the time the LCD occupies the SPI bus, freeing more bandwidth for SD writes.

V1.0 / V1.1 board not working correctly

• The pin definitions in board_pins.h are based on V1.2. Refer to the official schematic and update the pin numbers accordingly.