This article was inspired by the work of Mita Williams.
TL;DR:
The TRMNL OG set to a 2-bit palette provides an inexpensive, ready-to-go option for the Screenshot plugin at LibCal room booking.
What you need
A TRMNL device set up and connected to your account.
A LibCal room or space booking page that can be viewed without signing in.
Permission to view the room’s LibCal page and, if needed, to change its display or privacy settings.
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Choose the LibCal page
In LibCal, locate the room or space page you want to show. Depending on your LibCal setup, you can find rooms under Admin > Spaces & Equipment > Edit Location > Spaces & Categories.
Use the public-facing booking page URL for the specific room, not a general LibCal administration page. If the page includes a QR code or booking link, people can scan it from the TRMNL and reserve the room from their phone.
Add the Screenshot Plugin
In your TRMNL account, add the Screenshot Plugin.
Paste the URL for the LibCal room or space you want to display.
Give the plugin a name, such as
LibCal - Study Room 1.Set the refresh rate. A 15-minute refresh is a practical starting point for room availability.
Save the plugin and it will automatically be added to the playlist for your device.
The Screenshot Plugin loads the page as an image, so the LibCal page should be readable without interaction. If the page requires a login, a click, or a cookie consent step, the plugin will not show the room status you expect.
Set the TRMNL palette
For TRMNL OG, use the 2-bit palette for this layout. It gives the status block enough grayscale range to separate the room state, supporting text, and QR code while keeping the screen readable.
Example rendered screen in 2-bit grayscale. The room is available until 7:00 PM, with the next booking listed below and a QR code on the right.
A 1-bit palette also works, but dithering is more pronounced and can be harder to read:
The same style of screen rendered in 1-bit. Use it when you prefer a strictly black-and-white result, but compare the text and QR code at the actual viewing distance.
Verify the result
Wait for the plugin to refresh, or manually refresh the device.
Confirm that the screen shows the correct room and the current availability state.
Check that the next booking information is visible and current.
Scan the QR code from a phone and confirm that it opens the intended LibCal booking page.
When the room is in use
When the room has an active booking, the same screen can show the in-use state and the time it will become available again. The next booking can appear below the status area.
Example in-use state on TRMNL OG. The display shows when the room becomes available and the next booking information.
Is TRMNL BWRY an option?
We don't recommend it, because the color advantage isn't big enough to overcome the extra time (15-20 seconds) to update the screen. Here are examples on-device of available and in-use screens:
Anyone Can Benefit
If your library uses a public LibCal URL to display room status, you can do this on your own personal TRMNL device to decide whether you want to head over to your favorite study room!