I have an Arduino DUE, that is based on an Atmel SAM3X8E ARM Cortex-M3 CPU. It has 54 Digital I/O. It works on 3.3V.
I'd like to use it to drive individually 50 LEDs (for instance 50 optocoupler to replace a keyboard).
I know that the total DC Output Current on all I/O lines is 130 mA. So I think I should use a transistor or something to drive such a big amount of LEDs.
I'm not an expert on electronics and I'd like to know which component to use (even I think a darlington transistor should be ok).
Till now I'm driving the infrared led with a BC547 but I think I should replace it… Some hint?