I'm trying to control an LED-strip with an Arduino like an 8x8 matrix with a common anode (pic 1).
I put 2 NPN-transistors in the circuit and a LED-strip between them. The first transistors in pic 2 are 2N3904s, each one connected to an Arduino digital pin; the second one is a TIP120. The maximum current in the circuit is 0.4 A; 0.08 A for each strip.
I use simple Arduino code for it, like
digitalWrite(4, HIGH) (for any of the 2N3904s) and
digitalWrite(5, HIGH) (for the TIP120) to turn it ON, but after
digitalWrite(4, LOW) and
digitalWrite(5, LOW) the LEDs are still on. So I need to fix my circuit, but I don't know how.