I am starting work on a wearable project (kid’s Halloween costume) I am using an Arduino Nano, and I want to power the Nano and the LEDS from +5V USB power pack. I have two wiring questions:
Is it OK to just wire the +5V directly to the +5V pin of the nano using a cannibalized USB cable? I have seen conflicting information on the web. Some say it is fine, others say it is no-no. If I wire directly from the power pack to the +5V, can I still connect the USB to my computer for programming while the Nano is powered from +5V without fear of blowing out my USB port?
I plan to have three separate strings of APA102 LEDS (only about 20 pixels per string) just to make wiring easier. Is it OK to connect one string to the SPI pins, and the other to general purpose IO? Is FastLED smart enough to use HW SPI for the string connected to SPI and “bit-bang” the other strings?