Its very tight security, you can use in your home.
there is no need of any type of micro-controller. its only made by 555 timer IC.
you can set its distance between both device as per your required.
I caught this concept from Dhoom-2 movie, as the scene of "Antique sword robbery"
Step 1: Use Monostable Mode of 555 Timer & LDR Circuit
Monostable mode:- in this mode the 555 function as a "one-shot" pulse generator. Application includes timers, missing pulse detection, bounce free switches, touch switches, frequency divider, capacitance measurement, pulse width modulation and so on.
Ans use a LDR circuit. For laser operation.
Step 2: How to Be Set Output Delay Time
In monostable mode we can set delay time as per our requirement. with the help of resistor and capacitor,
Resistor is in ohm and capacitor is in farad.
there is a one formula for set output delay time. its very simple and easy.
Step 3: Interfacing and Main Circuit
This is full circuit diagram of laser security or can say 'Hidden crying laser'. you can make it easily. And use in your home. its very less costly and you can make it chargeable.
have a nice day. Be happy (: