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.

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.

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

I recommend simply using the docker-compose.yml file inside this repository, configure everything in there and run docker-compose up -d within the file's directory. This will pull the docker image, create the container with all environment variables from the file and run it in detached mode (using -d, so it continues running even when you exit your shell/bash/ssh connection). Additionally, you can then later use docker-compose pull && docker-compose up -d to update the image in case you want to update it.

You can then access the image by doing a simple GET request to e.g. http://localhost:5000/ to receive the most recent image (might take up to 60s after the first run).

Home Assistant related stuff:

* 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 etc.

The webhook setting is to let HA keep track of the battery level of the Kindle, so it can warn you about charging it. You need to do the following:

1. See below for a patch needed to make the Kindle Online Screensaver plugin send the battery level to this application.
2. Create two new helper entities in Home Assistant:
   1. a new input_number entity, e.g. input_number.kindle_battery_level
   2. a new input_boolean entity, e.g. input_boolean.kindle_battery_charging
3. Add an automation to set the values of these entities using a webhook:
4. Define this application's environment variable HA_BATTERY_WEBHOOK to the name of the webhook defined in the previous step. For multiple devices, HA_BATTERY_WEBHOOK_2, ... HA_BATTERY_WEBHOOK_n is supported as well.

Modify the following lines in the Kindle Online Screensaver extension's bin/update.sh (absolute path on device should be /mnt/us/extensions/onlinescreensaver/bin/update.sh):

...
if [ 1 -eq $CONNECTED ]; then
-     if wget -q $IMAGE_URI -O $TMPFILE; then
+     batteryLevel=`/usr/bin/powerd_test -s | awk -F: '/Battery Level/ {print substr($2, 0, length($2)-1) - 0}'`
+     isCharging=`/usr/bin/powerd_test -s | awk -F: '/Charging/ {print substr($2,2,length($2))}'`
+     if wget -q "$IMAGE_URI?batteryLevel=$batteryLevel&isCharging=$isCharging" -O $TMPFILE; then
        mv $TMPFILE $SCREENSAVERFILE
        logger "Screen saver image updated"
...

Modify the following lines in the HASS Lovelace Kindle 4 extension's script.sh (absolute path on device should be /mnt/us/extensions/homeassistant/script.sh):

...
- DOWNLOADRESULT=$(wget -q "$IMAGE_URI" -O $TMPFILE)
+ DOWNLOADRESULT=$(wget -q "$IMAGE_URI?batteryLevel=$CHECKBATTERY&isCharging=$IS_CHARGING" -O $TMPFILE)
...

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)