Improved Security Node

I've spent some time recently polishing the Security Node demo I made a while back to the point where it is no longer a demo.  It's now installed and functioning in my house.

Here are some of the changes:

• Integrated catisith2's keypad interface code
• Added logic so alarm system is run completely by the JeeNode
• Replicated original functionality of the DSC alarm control board
• Added circuit to control the (very loud) siren
• Send radio packets when events occur (alarm, arm, disarm, doors open/close)
• Handle remote commands via radio (mainly arm/disarm commands)
• Made a small "cheatsheet" with all the commands to attach inside the keypad panel

I've update the source code in my github repo.

I'm pretty satisfied with how the Security Node turned out but I have some things I'd like to change:

1. The alarm system runs fine locally but my ultimate goal is to have an external interface so I can receive texts when events occur and remotely arm/disarm the system.  I'm still trying to figure out how I want to do that.  JC Wippler is doing some interesting research along these lines.
2. There isn't much security with the arm/disarm radio messages, though I could encrypt the radio traffic pretty easily.
3. The final board works well but it looks ugly.  I'd like to redraw everything in EagleCAD and have a proper PCB made.
4. Adding a battery backup so the alarm will still work when there is a power outage.

Here are some pictures:

Security Node without JeeNode installed

Security Node installed

Keypad communicating with JeeNode