raspi

README.md

@@ -71,6 +71,106 @@ that machine: put `HandleLidSwitch=ignore` in
 `/etc/systemd/logind.conf.d/photobooth.conf` (needs root, applies even
 when the booth is not running) or use the desktop's own power settings.
 
+## Running on a Raspberry Pi (no desktop)
+
+The booth needs no desktop environment. On a console-only machine (no X
+or Wayland session) it automatically tells SDL to draw straight to the
+screen via the KMS/DRM driver, so it runs fine on Raspberry Pi OS Lite.
+
+1. **Install Raspberry Pi OS Lite (64-bit)** and boot with the screen,
+   camera, and mouse plugged in.
+
+2. **Install the system packages:**
+
+   ```bash
+   sudo apt install python3-venv cups fonts-dejavu-core
+   ```
+
+   (`fonts-dejavu-core` is for the contact-sheet footer text — Lite
+   doesn't ship it and the fallback font is tiny.)
+
+3. **Create a virtual environment and install the dependencies:**
+
+   ```bash
+   python3 -m venv ~/photobooth-venv
+   ~/photobooth-venv/bin/pip install pygame-ce opencv-python-headless pillow
+   ```
+
+   Note the **headless** OpenCV build: the regular `opencv-python` wheel
+   needs X libraries that Lite doesn't have, and the booth uses no GUI
+   features. If the pygame-ce wheel's SDL lacks the KMS/DRM driver
+   (`pygame.error: kmsdrm not available`), use the distro build instead
+   (`sudo apt install python3-pygame`) — the booth uses nothing
+   pygame-ce-specific.
+
+4. **Give your user access to the screen and input devices:**
+
+   ```bash
+   sudo usermod -aG video,render,input $USER   # then log out and back in
+   ```
+
+5. **Check which screen modes are available.** The Pi can only use modes
+   the display (or HDMI adapter) advertises:
+
+   ```bash
+   cat /sys/class/drm/card*-HDMI-A-*/modes
+   ```
+
+   If 800x600 isn't listed, set `[display]` width/height in `config.toml`
+   to one of the listed modes. For a 4:3 CRT behind an HDMI-to-coax
+   adapter, 720x480 fills the screen correctly (same trick as DVDs).
+   Everything scales to `[display]` automatically — no code changes
+   needed.
+
+6. **Set up the printer** with CUPS from the command line:
+
+   ```bash
+   lpinfo -v        # find the printer's URI (USB printers: usb://...)
+   lpinfo -m        # list available drivers
+   sudo lpadmin -p PRINTER -E -v <uri> -m <driver>
+   lpoptions -d PRINTER
+   lpstat -p -d     # verify
+   ```
+
+   Then set `printer = "PRINTER"` in `config.toml` to match.
+
+7. **Run it** from the console:
+
+   ```bash
+   ~/photobooth-venv/bin/python photobooth.py
+   ```
+
+### Starting automatically at boot
+
+Create `/etc/systemd/system/photobooth.service` (adjust the user and
+paths to match your setup):
+
+```ini
+[Unit]
+Description=CRT Photobooth
+
+[Service]
+User=pi
+SupplementaryGroups=video render input
+WorkingDirectory=/home/pi/nissaphotobooth
+ExecStart=/home/pi/photobooth-venv/bin/python photobooth.py
+Restart=on-failure
+
+[Install]
+WantedBy=multi-user.target
+```
+
+Then:
+
+```bash
+sudo systemctl enable --now photobooth
+```
+
+Quit with Esc/Q on a keyboard, or `sudo systemctl stop photobooth` over
+SSH. The keep-awake locks work the same as on a laptop (a Pi rarely
+sleeps anyway). The `auto-macally` camera lookup already waits ~15
+seconds for USB devices to enumerate, so no boot-order tweaks are needed.
+
 ## Customizing
 
 - **All settings** live in `config.toml` — camera choice, screen text,

photobooth.py

@@ -22,6 +22,11 @@ import time
 import tomllib
 from pathlib import Path
 
+# On a console-only machine (no X or Wayland session), tell SDL to draw
+# straight to the screen via KMS/DRM, so no desktop environment is needed.
+if not os.environ.get("DISPLAY") and not os.environ.get("WAYLAND_DISPLAY"):
+    os.environ.setdefault("SDL_VIDEODRIVER", "kmsdrm")
+
 import pygame
 
 import camera as cam