InkDeck

InkDeck is a custom E-Ink application OS for two ESP32-S3 readers: the 7.5-inch Book32 and the 3.97-inch Seeed Studio Sticky. It includes an EPUB reader, a Todo app, a Klipper printer monitor, and a local web interface for books, settings, and OTA updates.

Hardware

Target	MCU / flash	Display	Input	Ebook storage
Book32	XIAO ESP32-S3, 16 MB	7.5 inch, 800 x 480	One button	10 MB internal LittleFS
Seeed Studio Sticky	ESP32-S3, 32 MB	3.97 inch, 800 x 480	GT911 touch + three buttons + buzzer	MicroSD, with 23 MB internal fallback

Controls

Original Book32:

• Click: move to the next item or page.
• Long press: select, open, or go back depending on the app.

Seeed Studio Sticky:

• Tap a main-menu icon to open it and tap a library book to start reading.
• Tap the invisible left or right third of a reading page to turn backward or forward.
• Up/down buttons move backward/forward; the power/OK button selects.

Wiring

E-Ink Pin	Function	XIAO ESP32-S3 Pin
VCC	3.3V	3V3
GND	Ground	GND
DIN	MOSI	GPIO 9
CLK	SCK	GPIO 7
CS	Chip select	GPIO 44
DC	Data/command	GPIO 10
RST	Reset	GPIO 38
BUSY	Busy	GPIO 4

Button:

• Signal: GPIO 5
• Other side: GND

Battery sense:

• Voltage ADC: GPIO 1
• Measurement switch: GPIO 6, active high

The Sticky is a complete device and does not need external display wiring. Its board profile uses E-Ink SPI on GPIO 13/14/15/16/17/18 (enable GPIO 47), GT911 touch on GPIO 3/2/21/41 (enable GPIO 42), MicroSD CS on GPIO 8, and its PWM buzzer on GPIO 48. InkDeck uses the buzzer only for main-menu touchscreen taps; the eReader remains silent.

The Sticky build uses DIO flash with octal PSRAM. Do not change its flash mode to QIO: production Sticky hardware can watchdog-reset in the ESP32-S3 ROM before the second-stage bootloader finishes loading. Serial diagnostics use the device's CH343 UART bridge at 115200 baud.

Install From A Browser

The quickest installation method is the InkDeck Browser Installer. It works in desktop Chrome or Edge with a data-capable USB cable and does not require PlatformIO or a local development environment.

• Updating InkDeck flashes the firmware and web interface while preserving Wi-Fi settings, ebooks, and reading progress.
• Set up new hardware installs the bootloader, hardware-specific partition table, firmware, and web interface.

Choose either the Book32 or Seeed Studio Sticky hardware card before connecting USB.

The installer does not write to the dedicated ebook partition. If ESP Web Tools offers an Erase device option, leave it unchecked on a device that contains ebooks.

Install PlatformIO

The easiest path is Visual Studio Code plus the PlatformIO extension.

1. Install Visual Studio Code.
2. Install the PlatformIO IDE extension.
3. Install Git if it is not already installed.
4. Clone this repo:

git clone https://github.com/rolohaun/Book32.git
cd Book32

You can also use PlatformIO from the command line:

python -m pip install platformio

Flash From PlatformIO

Choose the matching environment:

# Original 7.5-inch Book32
python -m platformio run -e seeed_xiao_esp32s3 --target upload

# Seeed Studio Sticky
python -m platformio run -e seeed_reterminal_sticky --target upload

Then flash the matching web interface filesystem:

python -m platformio run -e seeed_xiao_esp32s3 --target uploadfs
# or
python -m platformio run -e seeed_reterminal_sticky --target uploadfs

The ebook storage partition is separate. These commands update firmware and the web UI, but they do not erase uploaded ebooks.

On a brand-new board, the firmware creates the internal ebook filesystem on first boot. Sticky mounts a MicroSD card at /ebooks when present and otherwise uses its internal fallback partition.

To watch boot logs:

python -m platformio device monitor

If upload fails because the board is not in bootloader mode, hold BOOT, tap RESET, then run the upload command again.

First Boot

Seeed Studio Sticky:

1. Power on the Sticky and tap the Wi-Fi icon.
2. Tap a network, enter its password on the touch keyboard, and tap Connect.
3. The credentials are saved and the assigned IP address appears on the main menu.

Original Book32:

1. Power on Book32 and connect to the InkDeck-Setup access point if WiFi is not configured.
2. Open 192.168.4.1 if the setup portal does not open automatically.
3. Choose your WiFi network and enter the password.
4. After connection, InkDeck shows its IP address on the main menu.

Open http://<INKDECK_IP>/ in a browser to manage books and settings after either device joins the network.

OTA Updates

InkDeck uses the public GitHub release feed:

https://github.com/rolohaun/Book32/releases/latest

No GitHub personal access token is required. Releases should include:

• firmware.bin
• littlefs.bin
• book32-sticky-firmware.bin
• book32-sticky-littlefs.bin

The device downloads those public release assets directly when you run an update from the web interface or the device menu.

Useful PlatformIO Commands

Build both firmware targets:

python -m platformio run -e seeed_xiao_esp32s3
python -m platformio run -e seeed_reterminal_sticky

Build the web UI filesystem image:

python -m platformio run --target buildfs

Flash firmware:

python -m platformio run --target upload

Flash web UI:

python -m platformio run --target uploadfs

Open serial monitor:

python -m platformio device monitor

Features

• Polished boot screen with E-Ink progress feedback
• EPUB reader with streamed chapter parsing, Unicode-stable progress, and boot resume
• PSRAM-backed JPEG/PNG illustrations with high-quality monochrome dithering
• EPUB cover thumbnails decoded on demand without writing extracted cover files
• Bounded 16 KB page index for fast backward navigation without unbounded cache growth
• Reader-only idle CPU scaling for improved battery life
• Library menu optimized for E-Ink
• Local web interface for uploading and deleting books
• Todo app
• Klipper printer monitor
• Battery indicator and charging status
• Public GitHub OTA firmware and web UI updates

The EPUB image pipeline is inspired by the MIT-licensed CrossPoint Reader. It scales images before applying Atkinson-style 1-bit dithering, preserving useful detail on the E-Ink panel while keeping temporary working data in PSRAM.

Partition Notes

InkDeck uses a hardware-specific custom partition table. Ebook storage is mounted separately from firmware and the web UI, so normal firmware and uploadfs updates do not overwrite it. Sticky uses partitions_32MB_sticky.csv; its SD card and internal fallback share the same /ebooks path.

Fresh hardware setup uses three pieces:

• python -m platformio run --target upload flashes the bootloader, firmware, and the custom partition table.
• python -m platformio run --target uploadfs flashes the 1 MB LittleFS web UI partition named spiffs.
• The ebooks partition (10 MB original, 23 MB Sticky fallback) is not flashed by PlatformIO. InkDeck formats it automatically the first time it sees that partition is blank.