Greetings, all. I’ve never posted to the fastled community but I’ve been following the group and working on my own installations/sculptures for over a year now. I’m so inspired by all of the work here and the level of support is astounding. I swear I will contribute more! But I haven’t been able to move forward with my project for months now because of one small issue… SPI CABLE LENGTH! GAHHHH.
Anyway, SPI amplification. I’ve searched through these posts and across the web for a while now but I haven’t found any straightforward explanations, or at least any that seem to apply directly to addressable leds. I don’t know. Maybe I haven’t been looking hard enough, but it just seems a bit over my head.
I’m currently working with WS2801 LEDs that require 12v power and both a clock and data signal. Ideally there would be a ~15ft three-pin cable between my controller and the LEDs with a separate power source for the LEDs (with common ground between the lights and arduino).
I keep hearing about the RS232/RS485/MAX3232 chips. From what I understand (likely not at all accurate) these kinds of chips electrically amplify signals! By… uh, taking an SPI signal, or any kind of signal with both data and clock lines and putting more voltage behind it…? And the signals have to go down wrapped cables, like a DMX or CAT5 cable!! Because… it electrically isolates the data and clock signals…? And then at the other end of the cable I can just plug right into the data and clock lines of the LEDs!! Or… no?
Is there a specific chip I should look at for this kind of application? It looks like the RS485 chip is the way to go?
And when I find the right one, I should just be able to take a look at the data sheet and figure out where the power, ground, clock, and data lines go?
Do chips like these require a specific voltage? I take it supplying +5v from the arduino wouldn’t be enough.
And at the other end of the signal, do I need to use a step down voltage converter? If I amplify the 5v SPI signal to 12v, and the WS2801 LEDs require 12v, I should be good to just plug right in to the led’s clock and data lines?
And does it HAVE to be a wrapped cable? I would love to use XLR cables, but I could move to DMX, and I would prefer not to use CAT5. But beggars can’t be choosers I guess.
Any help, any link to another discussion post, any resources would be greatly appreciated. Once I tackle this I will send my thanks, post my work, and have a beer. Thank you all!