Hi guys, I've been looking at this amazing arduino topic for the last 2 months and just finished recently my first arduino-based lightsaber ! However i'm facing a powering problem. Indeed, I'm using to 18650 cell wired up in series giving me a 8V output (i know that it can drop as low as 4.5V). The output of the batteries are directly wired to the vin pin of the arduino, but also to a DC-DC StepDown module. This module lower the voltage to 5.0V in order to power my 100leds WS2812B strip at 150 for brightness. My problem is that when I use a simple external power supply for the blade only (and powering the arduino via usb), everything works fine (even tho i had to change the code mutiple time for the arduino to support a 100leds, i don't know why). However when powering everything on the battery like I explained, the blade doesn't power (voltage is still measured between the strip) but the arduino still works (for sound, motion-detection....).
If the someone could tell me what's wrong, the help would be much appreciated !
I can provide code or schematics for more details.