An E-Ink Display for Home Assistant
You can now use the Invisible Display to show a Home Assistant dashboard!
A dashboard from one of our customers: solar output, home and car battery, the weather — and a reminder about the bins.
By combining a screenshotting add-on with a rendering add-on, you can put any dashboard you have built in Home Assistant onto the display. All on your local network, without any online services needed: the display asks your own machine for a new picture about once a minute, and never contacts our servers. You don't need an account with us at all.
How it works
Two Home Assistant add-ons, and about ten minutes. You need a Home Assistant installation that can run add-ons, on the same network as the display.
The first add-on takes a screenshot of a dashboard you have designed. Balloob's puppet add-on does this well and is a good starting point.
The second one converts that screenshot into the format the display expects and serves it on your network. One of our customers, Jon, packaged our reference server as a Home Assistant add-on for exactly this purpose: github.com/jonathon-m/ha-local-render-server
Add his repository under Settings → Add-ons → Add-on Store → ⋮ → Repositories, install Invisible Local Render, and point it at the screenshot. Then set up your display in our app, giving it the add-on's address on your network, for example http://homeassistant.local:8080. Plain HTTP — the display does not speak HTTPS on your local network.
The add-on is Jon's work rather than ours, so we cannot promise support for it. If you prefer to build your own, the protocol is two HTTP endpoints and we publish a working server in Python: github.com/Invisible-Computers/local-render-server
What it is good at
Electronic paper redraws slowly, and the display asks for a new picture about once a minute. It is a status board rather than a live panel.
That suits the things you want to see at a glance: today's agenda, the weather, energy prices, the shopping list, who is home, which bin goes out tomorrow. It is not suited to a camera feed, or to a graph you want to watch move.
Designing the dashboard
Build the dashboard at the size of the panel and it will look as sharp as print:
- 7.5 inch display — 800 × 480
- 10.2 inch display — 960 × 640
Set the same size as the viewport in the screenshot add-on. Bold text and clear blocks read well; thin grey lines and subtle shading do not survive a black-and-white screen. In the photo above, the sparklines come out as dither patterns.
