The document discusses using Arduino boards and the Nagduino library to monitor physical environments and send sensor data to Nagios for monitoring. Arduino allows reading inputs from sensors like temperature, humidity, and motion sensors using code. The Nagduino library facilitates sending passive check results from Arduino to Nagios via NRDP. A live demo shows a magnetic sensor detecting door openings and closings, sending alerts to Nagios. Future directions include supporting additional protocols and interfaces to expand physical monitoring with Nagios.

1. Monitoring the Physical World
with Nagios and Arduino
Trevor McDonald
tmcdonald@nagios.com
http://github.com/tmcnag

2. Who Am I?
● Support Tech at Nagios Enterprises
– tmcdonald on Support Forum
– Docs, Bugs, Testing, PPeerrll
● Other Things I Do:
– World Languages
– Computer Security
– Electronics

3. Who Am I Not?
● Affiliated with Arduino
– Not being paid to advertise
– All images copyright their respective owners
– <Legal disclaimer here>
● Iron Man

4. Who Am I Not?
● Affiliated with Arduino
– Not being paid to advertise
– All images copyright their respective owners
– <Legal disclaimer here>
● Iron Man (yet)

5. What's This Talk About?
● Physical Monitors:
– Temperature
– Humidity
– Light
– Motion
– Open/Close of Doors/Windows

6. How Do We Do That?
● Existing Solutions:
– Closed-source
– Limited scope
– Expensive* ($1,000+)
● Arduino:
– 100% open-source
– Customizable
– Cheap ($5 to $50)

7. What is Arduino?
● Arduino Uno
– 8-bit Microprocessor
– 32K Flash Memory
– 2K RAM
– 16 MHz Clock Speed
– Runs on 5V
– 14 Digital + 6 Analog I/O Pins

8. Assumptions
● You know a bit of C/C++
● You understand passive checks (NRDP)
● You understand the following:
– Flip switch up, light goes on
– Flip switch down, light goes off
– AKA “Digital logic”

9. How Does It Work?
● Hardware is attached to pins
● Each I/O pin either reads or writes data
– Reading might detect if a button is pressed
– Writing could turn on a LED or motor
● Pins can be configured for either task
● Regular C code is used to control pins
and handle program logic

10. A Simple Blink
● [ Picture of LED breadboard ]

11. A Simple Blink
● [ Example Blink sketch ]

12. A Simple Blink

13. Button Press

14. Button Press

15. Button Press

16. The Missing Link
● We're able to...
– Read the state of a button/switch
– Take action accordingly (light an LED)
● We want to...
– Send passive results to Nagios
● So we need...
– Networking capability (HTTP for NRDP)

17. Arduino Shields
● Stack on top of and expand an Arduino
– Relay shield for high-powered device control
– MP3 shield for adding quality audio output
– LCD + buttons shield for a basic UI
– Ethernet shield for network connectivity
● Relatively cheap ($30 to $60 on average)
● Save on RAM, CPU, code, and time

18. Ethernet Shield

19. Introducing Nagduino
● C++ “library” I built to facilitate NRDP calls
– No NSCA (not enough RAM for crypto)
– No SNMP Traps (not enough patience)
● Very small, very simple code
– 6 lines to get you going
● Bells + whistles not included
– No checking NRDP result
– Debug code? What debug code?

20. Putting It All Together
● Magnetic sensor attached to input
● Arduino checks sensor on a loop
● If open, send NRDP Critical to Nagios
– “Latch” to avoid repeat messages
● If closed, do nothing and loop
– Reset latch, re-check every 100ms
● Alert based on preferences/settings

21. The Hardware

22. The Code

23. The Code

24. Live Demo

25. Tying In With Nagios
● Graphing
– View historical information
– Capacity planning (XI)
– Use multistacked graphs for correlations (XI)
● Physical Event Handlers
– Turn on fan if temp is Warning
– Turn on AC if temp is Critical

26. Use Cases
● Applications in:
– Farming (soil moisture, temp, light)
– Security (light, motion, sound, contacts)
– Home Automation (temp, light, infrared LED)
– Beekeeping (Talk to Sally Reich)

27. Moving Forward
● Support for NSCA + SNMP Traps
● Web interface (CCM for Arduino checks)
● Beyond Arduino
– Raspberry Pi (I'm looking at you, Dave)
– Smartphone (Mobile environment readings)
– Intel Edison (Very cool)

28. Questions?
Thank You!

29. The End
Trevor McDonald
tmcdonald@nagios.com
http://github.com/tmcnag