Almost all inexpensive commercial LED flashlights use a 4.5V power supply—three AA or AAA batteries—because white LEDs require 3.3 to 3.5V to fully turn on. Thus ...
If you’re looking to control WS2812 (or Neopixel) LEDs using a microcontroller running at 3.3 volts, you might run into some issues. The datasheet tells us that a logic high input will be detected at ...