And, an aside: The assessment of the amount of current needed assumes you will ever program all of the LEDs to full white. If you know that will never happen -- e.g. if you plan to, for instance, only light say 10 at a time, or you plan to never have an LED light up all three colors at a time (i.e. "white"), then you might be able to get away with it.
Use the following formula to assess the maximum current demand:
(Summation of Red LED currents) + (Summation of Green LED currents) + (Summation of Blue LED currents) = Max current required.
Summation of currents means: adding up the currents of all the LEDs of that color (i.e. the internal LEDs in the WS2812B). Each LED current is a function of the 0 to 255 digital intensity value sent to that particular WS2812B TIMES 20ma.
For example: say there will only be, at most, three WS2812Bs active at a time. Using the following table of worse case LED intensity values:
| Module # | Red | Green | Blue |
|---|---|---|---|
| 1 | 150 | 200 | 250 |
| 2 | 200 | 100 | 50 |
| 3 | 30 | 70 | 90 |
The total current would be:
Red(150/25520 + 200/25520 + 30/25520) = 29.8ma
Green(200/25520 + 100/25520 + 70/25520) = 29.0ma
Blue(250/25520 + 50/25520 + 90/255*20) = 30.6ma
29.8 + 29.0 + 30.6 = 89.4ma total