Very simple flashing 8-LED ring and button on Raspberry Pi 3

Question

This is my first Raspberry Pi project that involves an LED ring with button control, and I have some very basic questions.

I am making a halloween costume with a Raspberry Pi and this SparkFun Lumenati 8-Pack LED. I don't really need it to be perfect, and am not too worried about dim LEDs, so my question is, can I power it directly from the Pi's 5v pin and ground? In a tutorial I found, they use a PCA9306 Level Translator Breakout, in this configuration. Should I bite the bullet and buy the breakout?

Additionally, I want to use a portable phone charging pack to power the RPI. It is 5V so I feel like it should work. I would plug it directly into the USB so I don't think I would need a voltage regulator. Thoughts?

Lastly, I'd like to have a button connected to the RPI that cycles the LED ring between 3 modes: flashing blue, flashing green, and flashing red. Should I connect the button to certain GPIO ports?

Thanks so much in advance.

Answer 1

LEDs power supply

Assuming those LEDs are similar to adafruit's dotstar leds, the maximum current is 0.48A (8 leds * 60 mA). According to this answer, you can use the +5V pin and ground to power your leds.

About the level shifter

The APA102C datasheet says that the input high threshold (VIH) is 3.5V (0.7*VDD), and the GPIO from the PI are 3.3V. So without the level shifter, you're out of spec.

Power bank

Running that out of a power bank should work, given the battery pack is rated for at least 5V 2.5A.

Button

Any GPIO should do, but you can have a look here.

About the PI

This is probably not the answer you're looking for, neither a good site for posting it, but an arduino (mini or nano) will probably be easier to program, and will consume less (so your battery pack will last longer).