10.3. The Laddie Front Panel

Our requirements for the Laddie front panel UI were that we be able to view either system status or log messages, and that we have the minimal set of commands necessary to manage the system. We gave Laddie's LCD UI three modes: Status, Logs, and Menu. The Status display reports whether there are any alarms, the Logs mode shows the last two log messages, and the Menu mode lets a user clear, test, enable, and disable an alarm zone. There are four buttons for navigating the menu system, and a flashing LED indicates an alarm in the system.

The Laddie LCD UI listens for log messages from logmuxd and opens a PostgreSQL/RTA connection to the alarm daemon (ladd). The DB connection to ladd is used for configuration changes and ...

Get Linux Appliance Design now with the O’Reilly learning platform.

O’Reilly members experience live online training, plus books, videos, and digital content from nearly 200 publishers.