1.5 v AA or AAA ea, and considering using just 2 or 3 depending on the LED at the end. From the prior replies it says that you need a steady power supply, that the voltage is too inconsistent using dry cell batteries to a XIAO. From what I understand, the XIAO should be able to control the voltage going out, but the other posts suggest intermediate steps, perhaps adding a resistor for the LED too. But just focusing on the input voltage, is it consistent enough to use as is without a buck booster?