I’m glad I found “Programming the Adafruit Trinket from your Raspberry Pi” here. It is very similar to what I want to do.
But I need a little clarification. The article starts off with this warning “Warning: Make sure you use the 3.3v Trinket, don’t connect a 5v one directly to your Pi!”. Then at the very end of the article it states, “Once you’re comfortable connecting the Trinket and the Pi you should switch to using the 5v pin on your Pi to power the Trinket, specially if you’re using the 3v output to drive something like NeoPixels”
So is that a contradiction or am I missing something? Or is my newbie electronics showing through here? Or is it saying that to use the 3.3v Trinket version because we are powering 3.3v sensors or LEDs or such but it’s ok to power it with 5V?
Also, if I do power it with 5V do I unplug the 3.3V jumper to the Trinket?
Lastly, I miss the part where the RPi talks to the Trinket. In my case, I want the RPi to tell the Trinket to flash the NeoPixel RGB LED a certain color and intensity for some duration and such. How do I do that?