How many WS2812B can teensy4.1 Drive ?

dallen

New member
How many WS2812B can teensy4.1 Drive ?

Hi,

i am currently costing out how much to build a 600x300 matrix using 16mm pitch neopixel strips so question, how many leds can the teensy4.1 drive ?

or put another way how many teensy4.1 would be required to drive 180,000 leds

I have 2 full screen applications NB a slide show pausing every 7 seconds and the second application is full motion video at around 25 to 30 FPS
Any advice greatly appreciated
 
OctoWS2811 library is the best way to drive lots of WS2812B's.

https://www.pjrc.com/teensy/td_libs_OctoWS2811.html

Despite the name, on Teensy 4.1 it can drive LEDs on more than 8 pins in parallel - all the way up to 55 (the full number of digital pins). This is a cool capability that not too many people are aware of.

It would be a good idea to add level converters to each pin you use, since some LEDs don't work properly with 3.3v signals.

The max practical length is about 500 LEDs per pin, due to timing reasons, so you could in theory drive 27,500 LEDs per Teensy 4.1. I don't know if there may be memory limitations that come into play.

If you do build something that large, good luck! In my experience, you will have some LEDs which are faulty and prevent all of the downstream ones from working until you cut them out and replace them.
 
Power delivery is a serious challenge for that many LEDs.

For example, if you budget for each LED to use 50 mA max when all 3 colors are fully on, with 5V power that's 0.25 watt per LED. So if you use 180,000 LEDs and you design for power to allow all to turn on fully, you're looking 45 kW power!

Remember, good switching power supplies are about 80% efficient. Cheap one, less so.... and you'll need so many that spendy power supplies probably aren't very attractive. If you end up with 68% efficient, you'll need over 66 kW from AC mains. Arranging for a service to deliver that much power isn't always easy. A common 20 amp, 240 volt service is only 4.8 kW.
 
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