kdorff / kindle-cal

Use an old kindle for a calendar/dashboard with nextjs 14

kindle-cal

kindle-cal is a simple webapp using the NextJS framework, develped using Typescript.

I'm repurposing an old Kindle Keyboard (3.4.3) to use as a dashboard for slowly changing information, such as a calendar or low-fidelity clock. The Kindle can display (4bit?) greyscale PNG images, but has very little processing power. This app can be used to easily generate a Dashboard and then render that dashboard as a PNG that is appropriate for a Kindle.

On the Kindle side, I'm using a modified version of https://github.com/kdorff/kindle-dash. I will be updating my fork with my changes (notably remoing the xh binary that was failing on my Kindle).

Getting the code running

Install node for your platform. I've tested with v20.11.1.

Fork the code, if you like.

Checkout the code. If you didn't fork my code, you can use

git checkout https://github.com/kdorff/kindle-cal.git
cd kindle-cal

Configure your .env.local file

TZ=US/Central
HA_URL=http://HA_IP:8123/api/states/input_number.kindle_keyboard_battery
HA_TOKEN=eyJhbGciOiJIU***WKMPk0GVGKqlFOMA

Setting TZ will define the timezone. If omitted, it will default to US/Central.

HA_URL and HA_TOKEN, if defined, will read battery state using the Home Assistant REST API. In this, reading the state for the input_number helper named input_number.kindle_keyboard_battery.

To start the application

npm install
npm run dev

Then visit

• http://localhost:3000 to view the current dashboard
• http://localhost:3000/png to view a rotated, greyscale PNG of the current dashboard

Running with docker compose

In the same folder as my docker-compose.yml file, I do

git clone https://github.com/kdorff/kindle-cal.git

which checks the project out into the folder ./kindle-cal.

Add a stanza to docker-compose.yml

  kindle-cal:
    build: ./kindle-cal/
    container_name: kindle-cal
    restart: unless-stopped
    ports:
      - 3400:3000
    environment:
      - TZ=US/Central
      - HA_URL=http://HA_IP:8123/api/states/input_number.kindle_keyboard_battery
      - HA_TOKEN=eyJhbGciOiJIU***WKMPk0GVGKqlFOMA

My update-and-restart.sh script, which also lives in the same folder as docker-compose.yml, updates all my docker compose containers and restarts each.

#!/bin/sh

# Update local git repos
here=`pwd`
cd ${here}/kindle-cal && git pull
cd ${here}

# Pull, rebuild restart all
docker compose pull &&
   docker compose build &&
   docker compose down &&
   docker compose up -d

The application should then be running on http://dockerhost:3400 where dockerhost is the name or ip address of the machine running docker.

Revisions

If you have great ideas, feel free to make a PR with suggested changes.

The content of the dashboard is within src/app/components/kindle-cal/kindle-cal.tsx