Diy Strobe LED Sun Glasses

Hi, i have got an arduino mega 2560 and led strips powered by 12v.
Can i use my arduino to open/close the circuit that is already battery-powered to make the leds flash how i want?
Thanks for your help!

Do you want independent control of each LED? If so you have a lot of rewiring to do.
If not and you just want to turn it on or off then you need to do this with a transistor that is driven from the arduino as the arduino only kicks out 5V at limited current on the output pins.
Use a circuit like the first one on this page. It matters not that it is showing a motor just substitute your glasses.

but if i already have the leds powered why do i need 5v (except to power the arduino)? the only thing i need is the arduino to press the button shown in the second pic.
anyway i need to power them all together, no wiring :sweat_smile:

Pushing the button will involve a voltage greater than 5V so you need a transistor.