etyper

Disclaimer: This project was mostly generated with AI assistance (Claude / Cursor). It has been tested on real hardware but may contain bugs or suboptimal patterns. Contributions and corrections are welcome.

E-Paper display driver and distraction-free typewriter for the WeAct Studio 4.2" E-Paper Module (SSD1683, 400x300 B/W) on the Orange Pi Zero 2W (Allwinner H618, Armbian).

Hardware

Display: WeAct Studio 4.2" E-Paper (SSD1683 controller, 400x300px)
- Compatible with Waveshare 4.2" V2 displays
SBC: Orange Pi Zero 2W (Allwinner H618, 64-bit ARM)
OS: Armbian (Debian-based)

Wiring

Follows the WeAct Studio Raspberry Pi pinout:

Display Pin	Header Pin	GPIO	Function
DIN / MOSI	Pin 19	PH7 (231)	SPI1 MOSI (hardware)
CLK / SCK	Pin 23	PH6 (230)	SPI1 CLK (hardware)
CS	Pin 24	PH5 (229)	Chip Select (GPIO)
DC	Pin 22	PI6 (262)	Data/Command (GPIO)
RST	Pin 11	PH2 (226)	Reset (GPIO)
BUSY	Pin 18	PH4 (228)	Busy signal (GPIO input)
VCC	Pin 17	3.3V	Power
GND	Pin 20	GND	Ground

Important: CS is controlled via GPIO (not hardware SPI CS). The hardware SPI1 CS1 on Pin 26 (PH9) is not used. This is because the WeAct pinout places CS on Pin 24, which is not the Orange Pi's SPI1 CS pin.

Typewriter Mode

etyper includes a distraction-free typewriter application inspired by ZeroWriter.

Features:

Portrait display (rotated 90 CCW, 300x400 effective resolution)
Auto-opens last document on startup
Autosave every 10 seconds
USB keyboard input (any standard USB keyboard)
Switchable keyboard layout: US QWERTY, UK QWERTY, DE QWERTZ, FR AZERTY, ES QWERTY, IT QWERTY, SE QWERTY, NO/DK QWERTY, Colemak, US DVORAK (Ctrl+K)
Full text editing with arrow key cursor movement
Word wrap, auto-scrolling to follow cursor
Partial refresh for fast typing response (~0.5s per update)
Time-based full refresh every 5 minutes to clean e-paper ghosting
Auto-start on boot via systemd service
Survives power outages (autosave + auto-start + e-paper retains image)

Keyboard Commands

Typing:

Key	Action
A-Z, 0-9, symbols	Insert character at cursor position
Space	Insert space
Enter	Insert new line
Tab	Insert 4 spaces
Backspace	Delete character before cursor
Delete	Delete character after cursor

Cursor movement:

Key	Action
Left arrow	Move cursor one character left
Right arrow	Move cursor one character right
Up arrow	Move cursor up one visual line
Down arrow	Move cursor down one visual line
Home	Jump to start of current line
End	Jump to end of current line

Shortcuts:

Shortcut	Action
Ctrl+S	Save document
Ctrl+N	Save current and create new document
Ctrl+Left	Switch to previous document
Ctrl+Right	Switch to next document
Ctrl+F	Toggle file server via Bluetooth (download docs in browser)
Ctrl+K	Choose keyboard layout (Up/Down to browse, Enter to select, Esc to cancel)
Ctrl+R	Force full display refresh (cleans ghosting)
Ctrl+Q	Sleep / wake toggle (saves on sleep)

Status Bar

The bottom of the screen shows: *doc_20260115_143022.txt L12:5 482c

* = unsaved changes (disappears after save/autosave)
L12:5 = cursor at line 12, column 5
482c = total character count

Running

Run manually:

sudo python3 typewriter.py

Run as boot service (auto-starts on power on):

sudo bash install.sh
# Or manually (replace /path/to/etyper with your actual install path):
sed "s|__INSTALL_DIR__|/path/to/etyper|g" etyper.service | sudo tee /etc/systemd/system/etyper.service
sudo systemctl daemon-reload
sudo systemctl enable --now etyper

Service management:

sudo systemctl status etyper    # Check status
sudo systemctl stop etyper      # Stop
sudo systemctl start etyper     # Start
sudo systemctl restart etyper   # Restart after code changes
journalctl -u etyper -f         # View live logs

Documents

Saved to ~/etyper_docs/ as plain .txt files
Filenames are timestamped: doc_20260115_143022.txt
Last opened document is tracked in ~/etyper_docs/.last_doc
On startup, the last document is automatically reopened with cursor at the end

File Transfer (Ctrl+F)

Download your documents wirelessly via Bluetooth PAN (Personal Area Network). No WiFi required — the etyper creates its own network over Bluetooth.

How it works:

Press Ctrl+F — Bluetooth powers on, the file server starts, and instructions appear on screen
On your computer, open Bluetooth settings and pair with "etyper" (auto-accepts, no PIN needed)
Once paired, open a browser and go to https://10.44.0.1 (accept the certificate warning)
Download individual documents or all at once as a .zip file
Press Ctrl+F again to stop — devices are disconnected and Bluetooth powers off

Notes:

Bluetooth is off by default and only activates during file transfer
Auto-shuts down after 5 minutes if you forget to stop it
Pairings are preserved — once you pair a device, it can reconnect next time without re-pairing
SSL certificate persists across reboots (stored in ~/etyper_docs/.ssl/)
Survives crashes: stale bridges and DHCP servers are cleaned up automatically on startup
Works best with desktop/laptop browsers — phone Bluetooth PAN support varies by device
If your browser forces HTTPS errors, try http://10.44.0.1:8080 as a fallback
Requires python3-dbus, python3-gi, and dnsmasq on the Pi

Setup

1. Enable SPI1

Add the SPI1 device tree overlay in /boot/armbianEnv.txt:

overlays=spidev1_1

Reboot. Verify /dev/spidev1.1 exists:

ls /dev/spidev*

2. Install dependencies and service

The easiest way is to use the included installer, which installs all dependencies, disables the conflicting system dnsmasq service, and optionally sets up auto-start on boot:

cd etyper
sudo bash install.sh

Or install manually:

apt-get update
apt-get install python3-spidev python3-libgpiod python3-pil python3-evdev \
               python3-dbus python3-gi dnsmasq openssl
systemctl disable --now dnsmasq   # prevent conflict with etyper's own instance

python3-libgpiod, python3-evdev, python3-dbus, and python3-gi must be installed via apt (not pip). dnsmasq is required for Bluetooth file transfer. The system dnsmasq service must be disabled to avoid a port conflict.

3. Run the typewriter

sudo python3 typewriter.py

Or to test the display separately:

python3 examples/hello_world.py

Usage

from epd42_driver import EPD42
from PIL import Image, ImageDraw, ImageFont

with EPD42() as epd:
    # Initialize and clear
    epd.init()
    epd.clear()
    epd.sleep()

    # Create an image
    img = Image.new("1", (epd.width, epd.height), 255)  # white background
    draw = ImageDraw.Draw(img)
    draw.text((50, 100), "Hello!", fill=0)

    # Display it
    epd.init()
    epd.display_image(img)
    epd.sleep()

API Reference

Method	Description
`EPD42(pins, spi_bus, spi_dev, spi_speed, spi_mode, gpiochip)`	Constructor with optional config
`epd.init()`	Initialize display for full refresh
`epd.init_partial()`	Switch to partial refresh mode (call after `init` + `display`)
`epd.display(buffer)`	Write raw buffer and full refresh (~4s)
`epd.display_partial(buffer)`	Write raw buffer and partial refresh (~0.5s)
`epd.display_image(image)`	Display a PIL Image with full refresh
`epd.display_image_partial(image)`	Display a PIL Image with partial refresh
`epd.full_refresh(buffer)`	Force a full refresh to clean ghosting
`epd.clear(color=0xFF)`	Clear to white (0xFF) or black (0x00)
`epd.sleep()`	Enter deep sleep (requires `init()` to wake)
`epd.reset()`	Hardware reset
`epd.close()`	Release GPIO and SPI resources
`EPD42.getbuffer(image)`	Static: convert PIL Image to raw buffer

Custom pin mapping

epd = EPD42(pins={
    "dc": 262,
    "cs": 229,
    "rst": 226,
    "busy": 228,
})

Technical Details

SPI: Hardware SPI1 at 4MHz, Mode 0. CS managed via GPIO.
Controller: SSD1683 (Solomon Systech)
Full refresh: ~4 seconds, no ghosting. Used on startup and every 5 minutes.
Partial refresh: ~0.5 seconds, slight ghosting. Used for typing updates.
Display buffer: 15,000 bytes (400/8 * 300). 1 bit per pixel, MSB first. 1=white, 0=black.
Deep sleep: ~1uA current draw. Requires hardware reset to wake.
Typewriter font: Atkinson Hyperlegible Mono Medium 16px, 28 chars x 15 lines in portrait mode. Line height follows WCAG 1.5x recommendation. Designed by the Braille Institute for maximum legibility on low-resolution displays. Falls back to DejaVu Sans Mono if not found. Licensed under SIL Open Font License 1.1.
File transfer: Bluetooth PAN (NAP) with auto-accept D-Bus agent, bridge networking, dnsmasq DHCP, and HTTPS (self-signed cert) + HTTP fallback. Bluetooth is powered off when not in use. Pairings are preserved across sessions; stale state is cleaned up on startup for crash resilience.

Project Structure

etyper/
  epd42_driver.py          # E-paper display driver (full + partial refresh)
  typewriter.py            # Typewriter application
  install.sh               # Installer (dependencies + systemd service)
  etyper.service           # systemd unit file
  requirements.txt         # Python dependencies
  README.md                # This file
  fonts/
    AtkinsonHyperlegibleMono-Medium.ttf    # Primary display font
    AtkinsonHyperlegibleMono-SemiBold.ttf  # Heavier variant
    AtkinsonHyperlegibleMono-Regular.ttf   # Lighter variant
    AtkinsonHyperlegibleMono-Bold.ttf      # Bold variant
    OFL.txt                                # SIL Open Font License
  examples/
    hello_world.py         # Basic "Hello World" demo
    test_patterns.py       # Diagnostic test patterns

Credits

WeAct Studio - Display manufacturer & reference C driver
Waveshare - Compatible Python driver reference
Atkinson Hyperlegible Mono - Display font by the Braille Institute (SIL OFL 1.1)

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Repository files navigation

etyper

Hardware

Wiring

Typewriter Mode

Keyboard Commands

Status Bar

Running

Documents

File Transfer (Ctrl+F)

Setup

1. Enable SPI1

2. Install dependencies and service

3. Run the typewriter

Usage

API Reference

Custom pin mapping

Technical Details

Project Structure

Credits

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Name		Name	Last commit message	Last commit date
Latest commit History 10 Commits
examples		examples
fonts		fonts
.gitignore		.gitignore
README.md		README.md
epd42_driver.py		epd42_driver.py
etyper.service		etyper.service
install.sh		install.sh
requirements.txt		requirements.txt
typewriter.py		typewriter.py

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etyper

Hardware

Wiring

Typewriter Mode

Keyboard Commands

Status Bar

Running

Documents

File Transfer (Ctrl+F)

Setup

1. Enable SPI1

2. Install dependencies and service

3. Run the typewriter

Usage

API Reference

Custom pin mapping

Technical Details

Project Structure

Credits

About

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