Overview

Many HP printers allow you to set their status LCD to whatever message you'd like. This has historically been used for evil ("ERROR: INTERNAL FIRE" and so on). This tool turns your printer into a useful feedback device, with small amounts of data fed to it at interval by long-running processes.

When you pass by on your way to do something more important, you can take a glance at this glowing blue LCD and know that you're seeing nearly-live data.

Requirements

PHP5.3+ with CLI and socket support compiled in.

Example Usage: Manual message set

$ ./hardset.php -t 192.168.1.79 an example messages

And, poof! Your HP printer should now display the message you've provided.

Example Usage: Running a service

$ ./service.php -t 192.168.1.79 -s Weather

This process will keep active until killed, and update your printer with the current temperature for your area. You can skip the command-line arguments by setting defaults in the config.php file located in the base folder.

Writing a new service

namespace PrintHack;

class SystemLoad implements DataService\DataService
{
	public function getMessage($options=array())
	{
		$uptime = trim(`uptime`);
		$parts = preg_split("/load average[s]?:\s+/i", $uptime, 2);
		return $parts[1];
	}
}

// And to use it...
$console = new Console;
$service = new SystemLoad;
$console->runService($service);

Other ideas

• Countdown to an important milestone
• Total website hits for the day
• A single stock price, or a collection that transitions each second
• Open tickets
• Current count of online Jabber users in a company
• @hplcd twitter message displayer
• Unread email count
• Order count for the day
• Average load time for your website
• Application build status
• Randomly chosen available domain name
• Specific currency exchange rate