Draftling

A distraction-free Markdown text editor for ESP32-S3-based development boards with reflective displays.

Supported hardware

Board	Display
Waveshare ESP32-S3-RLCD-4.2	4.2" reflective LCD, 400x300

Hardware selection

Before building, select the target board with idf.py menuconfig. Navigate to DRAFTLING Configuration > Hardware Model and choose the board you are building for:

• Waveshare ESP32-S3-RLCD-4.2 -- 4.2" reflective LCD (400x300)

The display resolution and driver are configured automatically based on the selected model. You can also adjust the Display rotation angle in the same menu.

The user connects a Bluetooth keyboard and edits Markdown files stored on the SD card. The reflective LCD needs no backlight and works well in daylight. On request the device connects to WiFi and synchronizes files with a remote Git repository via the GitHub REST API.

Hardware

Feature	Waveshare RLCD-4.2
MCU	ESP32-S3 (16 MB flash, 8 MB OPI PSRAM)
Display	4.2" reflective LCD, 400x300, SPI
Storage	MicroSD (SDMMC 1-bit)
Input	BLE HID keyboard
Connectivity	WiFi 802.11 b/g/n
Wake from sleep	GPIO18 button

Features

• WYSIWYG Markdown editing on reflective display
• Bluetooth keyboard input with auto-discovery and pairing
• File browser to open and manage .md files on the SD card
• Markdown rendering: headings (H1-H4), bullet and numbered lists, blockquotes, code fences, horizontal rules, inline bold/italic/code
• Gap buffer text engine for efficient editing (256 KB document limit)
• WiFi station mode with credentials from NVS or /sdcard/wifi.cfg
• Git sync via GitHub REST API (pull and push .md files)

Keyboard Shortcuts

Shortcut	Action
F1	Open settings menu (BLE, WiFi, Git, Layout)
Arrow keys	Move cursor
Home / End	Start / end of line
PgUp / PgDn	Scroll by page
Ctrl+S	Save file
Ctrl+O	Open file browser
Ctrl+N	New file
Ctrl+L	Cycle keyboard layout
Ctrl+G	Git sync (pull + push)
Ctrl+W	Toggle WiFi (connect / disconnect)
Ctrl+Home/End	Start / end of document
Ctrl+Left/Right	Word movement
Escape	Switch to file browser

Keyboard Layouts

The editor supports four keyboard layouts that can be switched with Ctrl+L or through the F1 menu:

Code	Layout
US	US-English (QWERTY)
UA	Ukrainian (Cyrillic)
DE	German (QWERTZ with umlauts)
FR	French (AZERTY with accents)

The current layout is shown in the title bar.

Configuring enabled layouts

The set of compiled-in keyboard layouts is configurable via idf.py menuconfig under DRAFTLING Keyboard Layouts. Each layout can be independently enabled or disabled. By default US-English and Ukrainian are enabled. Disabling unused layouts saves flash space.

Building

Requires ESP-IDF v5.3 or later.

idf.py set-target esp32s3
idf.py build
idf.py -p /dev/ttyACM0 flash monitor

If you update sdkconfig.defaults or pull new changes, delete the generated sdkconfig so the defaults are re-applied:

rm -f sdkconfig
idf.py set-target esp32s3
idf.py build

Menuconfig Options

Run idf.py menuconfig to open the interactive configuration UI. Draftling adds two custom menus described below. All other options (Bluetooth, LVGL fonts, etc.) use the ESP-IDF defaults from sdkconfig.defaults and normally do not need to be changed.

DRAFTLING Configuration

Found at the top-level DRAFTLING Configuration menu.

Option	Type	Default	Description
Hardware Model	choice	Waveshare ESP32-S3-RLCD-4.2	Select the target board. Display resolution and driver are set automatically.
-- Waveshare ESP32-S3-RLCD-4.2			4.2" reflective LCD, 400x300
Display rotation angle	choice	0 degrees	Rotate the display by 0, 90, 180, or 270 degrees.

DRAFTLING Keyboard Layouts

Found at the top-level DRAFTLING Keyboard Layouts menu. Each layout can be independently enabled or disabled. Disabling unused layouts saves flash space.

Option	Default	Description
US-English (QWERTY)	y	Standard US keyboard layout
Ukrainian (Cyrillic)	y	Ukrainian Cyrillic layout
German (QWERTZ)	n	German layout with umlauts
French (AZERTY)	n	French layout with accents

Configuration Files

Place these on the SD card root:

WiFi (wifi.cfg)

MySSID
MyPassword

Git Sync (git.cfg)

repo_url=https://github.com/user/repo
branch=main
token=ghp_xxxxxxxxxxxx
path=docs/

The token is a GitHub Personal Access Token with repo scope. Keep this file private.

Project Structure

main/               Application entry point, pin definitions, Kconfig
components/
  display/           Display driver (RLCD SPI) and LVGL v9 port
  sd_card/           SD card (SDMMC) file operations
  ble_keyboard/      BLE HID keyboard host (Bluedroid)
  kb_layout/         Keyboard layout translation (US/UA/DE/FR)
  fonts/             Custom LVGL fonts (Latin, Latin-1 Supplement, Cyrillic)
  editor/            Gap-buffer editor, Markdown parser, LVGL UI, menu
  wifi_manager/      WiFi STA connection manager
  git_sync/          GitHub REST API file synchronization
  standby/           Deep-sleep / standby timer manager

License

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