Hello Arduino Community!
New to electronics but thanks to arduino I am an addict.
I am creating a laser alarm system for my Escape Room. I am using this build as a basis : http://www.instructables.com/id/Laser-Tripwire-Alarm/
However I want my system to be more complex. I want my alarm system to be connected to an arduino and if someone breaks a beam a signal is sent to the 'clock' arduino that then takes time of the clock. I would to have the alarm system disarmed via a code combination being entered correctly into the arduino.
My questions are:
What shields do I need if any in order to accomplish this?
Could I make several different alarm systems that could send a signal back to the original clock? Bluetooth? Wifi? What's easiest and cheapest!