How Does the LED Sign Work?

The infrastructure to print pages from the SCE website works well to control other peripherals. Writing to the LED sign is slightly simpler than printing and only involves Core-v4, AWS SQS and a Quasar. Below is a high level diagram of the sign messaging system.

To demonstrate the functionality of the LED sign, let's start at Core-v4's webpage to update the sign.

Let's fill out the led sign page with the below content:

Reading Messages from SQS

After the user submits data to update the sign, Core-v4's backend pushes a message to a Queue in Amazon's Simple Queue Service (SQS). Below is an example message pushed to the queue:

{
  "location": "https://bucketname.s3.amazonaws.com/folder/0.4844380944000606.pdf",
  "fileNo": 0.4844380944000606,
  "copies": 1
}

Forwarding messages to the LED Sign

On the sign, the received message translates to the command:

./sce_sign.exe \
 --set-speed <speed> px/vsync \
 --set-background-color <background color>
 --set-font-color <font color> \
 --set-border-color <border color> \
 --set-font-filename ./10x20.bdf \
 --set-brightness 66% \
 --set-text <text here>

the sign would show the message with the below colors: