It's not a real flash pattern used by police.
Just a few loops programmed by me to demonstrate some possibilities.
I AM NOT RESPONSIBLE FOR THE ACTIONS OR CONSEQUENCES REGARDING THIS TUTORIAL.
Use it only indoors and in private property!
It is not permitted to impersonate a police officer!
Step 1: Get Some Scanner Rgb Led's
Find out how to get the scanner rgb leds in my other instructable.
Also possible with normal rgb leds. (I used common anode rgb leds)
Step 2: Connect the RGB Leds With the Arduino
I used the same type of scanner leds (from HP printer) as in my other instructable,
so the pinout is still: green, red, blue, common anode (from top to bottem)
If you use other leds, the order can be different!
I don't know the exact specifications of this led,
so I used resistor values slightly higher than probably necessary.
red: 200 Ohm
blue: 150 Ohm
green not used
I used a Arduino Nano here, but it will work equally well with the other Arduino types.