How can I boost current to multiple IR LEDs


Hi, I've been working on a project with an arduino to use it as a TV-B-gone, now i know this has already been done and I have found lots of helpful documentation and code so far. I've wired up a matrix of LEDs in a 4x5 pattern exactly like this one https://www.instructables.com/image/FRG2JXC3ALEP282OH6/Complete-the-circuit.jpg taken from this project https://www.instructables.com/id/Ultra-TV-B-Gone/ . The design works, but with the setup I have now, i'm just supplying whatever current the arduino is outputting to the LEDs, I know I need some resistors and a transistor and thats what I need help with. I did also buy a 2N3904 transistor like the one in the project however, when I wire it up, nothing works. The lowest resistor I have is 220 ohms and I've tried wiring that up in various places throughout the circuit. Does anyone have any tips that would help me maximize the range for this LED matrix? thanks, ill be taking circuit classes next semester so one day ill be able to figure this out myself.

caitlinsdad6 years ago
Look up charlieplexing. I believe that is how you light up a matrix of LEDs.