That’s my problem…the LED power is NOT lowish. I live across from a cove on Atlantic ocean, highway where viewing of my displays (whatever they are) is about 700 feet away. I need POWER in the LEDs and the WS2812 doesn’t have it. (I have some sitting on my bench). BTW, the WS2812 is a WS2811 (the chip I’m using) with a 5050 RGB pixel attached. All I’m doing is removing the low power pixel, replacing it with a 3W jobby and adding drivers. Not really a FET guy, I’ve always used BJTs.
Having said this, all I need is FETs with 200-300 mA capability for each pixel, not large current by any means. I haven’t breadboarded the design yet so not sure if it will work (as you attest to in your email). I can still use BJTs if I have to, e.g. 2N3906 in TO92 package. I bought some quad Darlington arrays (STA475) from Digikey, and just love using them: lots of juice, easy to layout, minimal wiring.
I’ve constructed an 8 x 32 matrix (second photo) using 2981->FETs for columns and higher power FETS for the rows (since they have to drive 32 pixels). I breadboarded this circuit to make sure it works. Attached is logic board (first photo) to drive it using an Atmega 328, same as in Arduino UNO, but I made space for an ESP32 for more punch if required. (I use slower I2C because of my familiarity with it. Previous version used 74HC575 latches)
Here’s a video I made of two 8 foot Christmas light displays (can be seen from 700 feet away) using the high power pixels as in the design we are talking about, but using 2981 drivers and medium power BJTs. I limit the LED current to about 100 mA (determined empirically) and use 12Volts for the pixels. If I used 15 volts….brighter.