Arduino Notifier with telnet interface

Introduction

The Notifier was my first project using the Arduino.  The objective was to create a simple mechanism to alert when tickets in our service desk were getting close to their SLA limits.  It was easy enough to fit all together:

• • A Nagios plugin monitors our OTRS service desk

  • When certain ticket queues are close to violating their SLAs the plugin runs a script that opens a telnet session with the Notifier, checks the current status and then executes the appropriate alerts

  • The plugin turns off the LED when the ticket(s) in violation has been handled.

The telnet interface and commands

Telnet is an ancient protocol from a more civilized age.  It's simple to use and script into other open source systems.  Below is the help menu for the notifier:

Circuit Description

The high output LED is a VERY powerful light and would require additional driver circuitry if one wanted to use it to its maximum.  In this case, the 220 ohm resistor turns the LEDs on at only 10% their maximum power --less than 20mA.  As shown in the video below, the brightness is plenty for the required application.  20mA is half of what each digital pin on the arduino can source.  All together the 3 LED channels only require max 60 mA so our arduino can handle this just fine.  Add another 13mA or so for the beeper and we are still well within the limits.

Notifier Demonstration