Home Assistant Lovelace Kindle Screensaver

This tool can be used to display a Lovelace view of your Home Assistant instance on a jailbroken Kindle device. It regularly takes a screenshot which can be polled and used as a screensaver image of the online screensaver plugin.

If you're looking for a way to render your own HTML, see my other project hass-kindle-screensaver which renders a React page and can be adapted to your specific needs.

Sample image

Features

This tool regularly takes a screenshot of a specific page of your home assistant setup. It converts it into the PNG grayscale format which Kindles can display.

Using my own Kindle 4 setup guide or the online screensaver extension for any jailbroken Kindle, this image can be regularly polled from your device so you can use it as a weather station, a display for next public transport departures etc.

Usage

You may simple set up the sibbl/hass-lovelace-kindle-screensaver docker container. The container exposes a single port (5000 by default).

You can access the image by doing a simple GET request to e.g. http://localhost:5000/ to receive the most recent image.

Home Assistant related stuff:

Env Var	Sample value	Required	Array?*	Description
HA_BASE_URL	https://your-hass-instance.com:8123	yes	no	Base URL of your home assistant instance
HA_SCREENSHOT_URL	/lovelace/screensaver?kiosk	yes	yes	Relative URL to take screenshot of (btw, the ?kiosk parameter hides the nav bar using the kiosk mode project)
HA_ACCESS_TOKEN	eyJ0...	yes	no	Long-lived access token from Home Assistant, see official docs
LANGUAGE	en	no	no	Language to set in browser and home assistant
PREFERS_COLOR_SCHEME	light	no	yes	Enable browser dark mode, use light or dark.
CRON_JOB	* * * * *	no	no	How often to take screenshot
RENDERING_TIMEOUT	10000	no	no	Timeout of render process, helpful if your HASS instance might be down
RENDERING_DELAY	0	no	yes	how long to wait between navigating to the page and taking the screenshot, in milliseconds
RENDERING_SCREEN_HEIGHT	800	no	yes	Height of your kindle screen resolution
RENDERING_SCREEN_WIDTH	600	no	yes	Width of your kindle screen resolution
ROTATION	0	no	yes	Rotation of image in degrees, e.g. use 90 or 270 to render in landscape
SCALING	1	no	yes	Scaling factor, e.g. 1.5 to zoom in or 0.75 to zoom out
GRAYSCALE_DEPTH	8	no	yes	Ggrayscale bit depth your kindle supports
COLOR_MODE	GrayScale	no	yes	ColorMode to use, ex: GrayScale, or TrueColor.
DITHER	false	no	yes	Apply a dither to the images.
REAL_TIME	false	no	no	Disables cron and renders images as they are requests to save CPU
REAL_TIME_CACHE_SEC	60	no	yes	How long to cache images for when REAL_TIME is set to true
REMOVE_GAMMA	true	no	no	Remove gamma correction from image. Computer images are normally gamma corrected since monitors expect gamma corrected data, however some E-Ink displays expect images not to have gamma correction.
MQTT_SERVER	``	no	no	MQTT hostname to report values to
MQTT_USERNAME	``	no	no	MQTT authentication username if required
MQTT_PASSWORD	``	no	no	MQTT authentication password if required

* Array means that you can set HA_SCREENSHOT_URL_2, HA_SCREENSHOT_URL_3, ... HA_SCREENSHOT_URL_n to render multiple pages within the same instance. If you use HA_SCREENSHOT_URL_2, you can also set ROTATION_2=180. If there is no ROTATION_n set, then ROTATION will be used as a fallback. You can access these additional images by making GET Requests http://localhost:5000/2, http://localhost:5000/3.png etc.

You may also simply use the docker-compose.yml file inside this repository, configure everything in there and run docker-compose up.

Other endpoints

From time to time, you may need to restart the process. You can do this by sending a GET request to /exit endpoint. This will exit the process. Simply set your docker container to restart: unless-stopped to automatically restart it.

http://localhost:5000/exit

Advanced configuration

Some advanced variables for local usage which shouldn't be necessary when using Docker:

• OUTPUT_PATH=./output.png (destination of rendered image. OUTPUT_2, OUTPUT_3, ... is also supported)
• PORT=5000 (port of server, which returns the last image)
• USE_IMAGE_MAGICK=false (use ImageMagick instead of GraphicsMagick)
• UNSAFE_IGNORE_CERTIFICATE_ERRORS=true (ignore certificate errors of e.g. self-signed certificates at your own risk)

Docker

There is a automated build on the Docker Hub. lanrat/hass-screenshot

Docker Compose Example

version: '3.7'

services:
  hass-screenshot:
    container_name: hass-screenshot
    image: lanrat/hass-screenshot
    deploy:
      resources:
        limits:
          memory: 1G
    environment:
      - TZ=America/Los_Angeles
      - HA_BASE_URL=HOME_ASSISTANT_URL
      - HA_ACCESS_TOKEN=HOME_ASSISTANT_URL
      - LANGUAGE=en
      - MQTT_SERVER=MQTT_SERVER_IP
      - REAL_TIME=true
      - RENDERING_DELAY=2
      - COLOR_MODE=GrayScale
        # image 1
      - HA_SCREENSHOT_URL=/lovelace-infra/hud1?kiosk
      - RENDERING_SCREEN_HEIGHT=825
      - RENDERING_SCREEN_WIDTH=1200
      - GRAYSCALE_DEPTH=3
        # image 2
      - HA_SCREENSHOT_URL_2=/lovelace-infra/hud2?kiosk
      - RENDERING_SCREEN_HEIGHT_2=800
      - RENDERING_SCREEN_WIDTH_2=600
      - GRAYSCALE_DEPTH_2=4
        # image 3
      - HA_SCREENSHOT_URL_3=/lovelace-infra/hud3?kiosk
      - RENDERING_SCREEN_HEIGHT_3=800
      - RENDERING_SCREEN_WIDTH_3=600
      - GRAYSCALE_DEPTH_3=4
    restart: unless-stopped
    ports:
      - 5000:5000
    healthcheck:
      test: "wget --no-verbose --tries=1 --spider http://localhost:5000/ || exit 1"
      interval: 60s
      timeout: 5s
      retries: 3
      start_period: 60s