I know this is not something too complicated but i don't know how to do it.
I have a signboard that i made with 60 led. 10 led in series. and so on in parallel 6.
I use a charger from a computer that gives me 19 v. to this point it all works fine. but what i can't do is to connect them to the arduino(all together) and make them blink.
[u]Here[/u] is a circuit using a transistor to control a solenoid. You can use something similar to power your LEDs. (You don't need the diode with a non-inductive load like LEDs.)
If you want to blink all of the LEDs together, you only need one transistor.
i made with 60 led. 10 led in series. and so on in parallel 6.
I use a charger from a computer that gives me 19 v. to this point it all works fine
Are there any current-limiting resistors? (In case you don't already know this, LEDs are "current operated" and you shouldn't apply a fixed voltage.)