(Thought) I finished a project tonight until final testing when I tried using all components together. It consists of a Wemos D1 Mini which controls x6 standard LEDs + a WS2812B strip (29 LEDs). When I test the x6 LEDs, they work great. When I test the WS2812B strip, it works great. When trying to use everything together, no bueno.
It seems that when everything's on, the power from the LEDs is leaking into the WS2812B strip as it starts acting really funky once I turn on the LEDs. Below's a diagram of the setup. Is there an issue with how I've got it all together and if so, what should I d to resolve?
One possible problem is that you're using the WS2812B outside its specification. The minimum VIH is 0.7 time VDD.
0.7 x 5V equals 3.5V, your Wemos pin will output 3.3V max. If you add additional load (e.g. all normal leds on), that 3.3V might drop because the voltage regulator on the Wemos board might not be able to deliver sufficient current.
The (often given) advise is to use a 74HCT14 between the Wemos and the strip; you need two of its ports in series.
Try a resistor in series with the data input of the strip, ideally around 500R, and a large cap, like 4700uF, across the power pins near the start of the strip.
It may be only just working, on the edge of not working, because of the signal levels, as @sterretje mentioned. When that happens, small changes elsewhere in the circuit, like other LEDs switching on, can push things just over the edge, causing strange effects. I have had similar problems with esp8266 and ws2812, where it worked ok but if I touched some of the bare pins with a finger, it would go crazy. Remove my finger and it worked ok again. It was so close to the edge of working/not working.
