okay, I have a question, I have a 3 meter strip of ws2812b’s on the way, want to make a light painting rig with them. need help with reading either a image file or a csv file from the teensy 3.6’s built in sd card slot to do it, or do it the harder way and read a image in python and then write the code to hard drive I can compile to send to the teensy 3.6 anyone have any help, I havent been able to wrap my head around the sdfat examples for the teensy to understand what I want to do…
You can use the sdfat library to read files. Rather than CSV files, you can process your images and save as a BMP file, and then read the *.bmp file in binary (with the data for each pixel being three 8-bit binary values, just what you want to feed fastLED - tho the order might be different.).
I haven’t been doing that for a while, but I posted some code here almost 4 years ago. It works; once you have it going you can remove the print statements to run faster.
https://plus.google.com/101338095167604531927/posts/WG6opgMYEjV
Note that by convention BMP files are read from the bottom up; if that’s inconvenient, you can invert the image before saving.
I like the trick of inverting the image so you can read from the begining of the file. If you’re there processing the file already… why not! 
Yep, to invert the image vertically, you don’t even need to write any code - many image tools can do that.
I glanced through it and hope I can cut and paste then figure out how to give it the data it needs, and figure out how to use the built in sd card on the teensy 3.6
Okay may have bitten off more than I can chew. Haven’t been able to figure out what I’m missing for the posted code snippet
and the led strips arrived. so I have 562 leds.
hey zeph can you give me some help with your code?