The Low Power Digital Signage app runs on top of Notehub. As such, to run this sample you’ll need to create a Notehub account, start a new Notehub project, and configure a handful of environment variables.
The app uses environment variables
for storing project settings that need to be shared and synchronized across
For this project all environment variables need to be set up at the fleet
level, allowing you to configure different settings on different groups of
devices, if necessary.
Notehub creates an initial fleet for you when you start a new project, and you
can use that for setting your initial variables.
Navigate to your fleet in the navigation menu, and then click the Settings
Click the Environment tab.
Scroll down to the Fleet environment variables heading, and define the
two variables below.
display_values which is a semicolon-delimited (;) string of text to display and/or bitmap images to load from an SD card to the e-ink display. If this variable has a single value (either text or an image name), that will be loaded. Otherwise, the values are loaded into an array and the host will display one item at a time using the display_interval_sec variable or a default value, if not set.
display_interval_sec is the number of seconds to display text or an image on the screen before rotating to the next item in the list.
With both defined, click the blue Save button.
With this your Notehub backend is fully configured, and you’re ready to start
setting up your hardware.
The assets/bitmap/ folder contains a number of bitmaps formatted for the 2.13" display. Simply copy these onto the root of a FAT formatted MicroSD card, and the firmware for this project will detect them.
If you want to show your own images on the display, see this guide for detailed instructions on formatting and saving images for e-ink displays. Make sure to crop your images to 250x122 for display on the 2.13" screen.
Once the app is running, you can update the display using the environment variables above, either using the Notehub UI or one of the shell scripts in the scripts folder.
The scripts use the Notehub API, so you'll need follow the instructions here to get an authentication token.
You'll also need your Notehub project's UID, which you can find in the Settings screen. For setting fleet variables, you'll need the Fleet UID, which you can find on the Settings tab for your fleet. For device variables, you need the Device UID, which you can find on the device screen.