Hey guys, looking for some project advice for a spaceship bike I am building for burning man. I want to outline the spaceship in 144/m LED strips. This would consist of 4 lines of about 500 LED’s, two lines of 250 LED’s, one line of 300 LED’s, and 5 lines of 40 LED’s. This comes out to 12 lines with a total of approximately 3000 LED’s. I was thinking about using APA102 strips since they are a little cheaper than WS2812 and have faster data rates.
Question 1: Any other 144/m strips I should be looking at instead of APA102?
Question 2: What is the best microcontroller/ set up for this? Would a single Teensy 3.6 and some 3.3 to 5v logic level shifters be able to handle everything? Or would something else be required/better? I’ve seen some large projects using the OctoWS2811 Adaptor, but that seems to only be for WS2812.
Question 3: Can anyone point me in the right direction on the best way to mirror part of a strip to another strip? Please see the attached diagram picture at the bottom. On the diagram, the left line will be a strip of 500 leds. I would like to have a separate line of about 150 leds on the right part of the circle that would display the same thing as the leds on the left part of the circle. Would the best way be to write a for loop with something like leds2[0+i] = leds1[200+i]? Or is there a FastLED library function that does this more efficiently?
Thanks!
Mirroring is easy. Just split the data line to the two sides you want to mirror. It’ll just mirror as you would expect.
If you can deal with the wiring the apa102 with it setup as one single long strip is probably fine on a teensy 3.6 since the data rate is high enough to still give you a good frame rate even when you are clocking out all 3000 LEDs.
Otherwise parallel output only works on ws2812 family chips I think. Someone correct me if I’m wrong on that, been out of the loop a little while now.
The easiest set up which is likely to have the fewest issues to fix is a teensy 3.x and an OctoWS2811 level shifter with WS2812 style LEDs.
As for mirroring data from one part of the setup to another, FastLED does indeed have a handy new function. (Ignore the warnings about it being new and unstable, it’s not new anymore and it is 100% stable.)
@Jeremy_Spencer agreed too long and you have to start clocking back. But even at 11mhz you will get 800fps on 3000 LEDs I think.
Also no need to duplicate the mirrored LEDs in code, save the runtime and just wire it up to mirror for you. I did this the last couple of years on my bikes to great effect.
@Ben_Delarre I’ve had significant problems with only 600, they were in a complicated layout, but with short data lines. I had to split it into three sections and drive then separately in the end.
Mirroring strips in code gives much more flexibility than doing it with wiring. On my hat, 90% of the time I have both sides the same, but sometimes I don’t.
A teensy 3.x, especially a 3.5 it 3.6, running only 3000 LEDs will have plenty of clock cycles to spare.
Did you try lowering the bus speed?
@Ben_Delarre of course, no joy at even 1MHz
Crazy… Cheap Chinese hardware is a finicky beast!
@Ben_Delarre taming it is half the fun 
Are you set at 144? 60 looks good and it’s easy to solder when, not if, you need to splice.
@Jeremy_Spencer Thanks for pointing out issues with long APA102 runs. I’ll stick to WS2812 then. Also, CRGBSet looks perfect! Wow that enables so many cool ideas relatively easily. Going to start playing around with this immediately.
@Scott_Schipper I’m putting the LED’s in HDPE tubing. I’ve found that 144/m lets you get very close to the surface which gives it a very cool neon effect. 60/m has to be further away and gets a little less vibrant. I know using 144/m will be higher cost and more work, but I think it’s worth it for my application.
Thanks, guys.
@David_Specht for that many LEDs in one go, buy direct from WorldSemi - they are just as competitive as the Aliexpress sellers and that way you will be sure you’re getting quality and the real McCoy.
