Does anyone have tips on how to fade from one hue/color to a different

Josh_I · January 4, 2015, 2:45am

Does anyone have tips on how to fade from one hue/color to a different hue/color on analog strips (But not cycle through the entire hue)?

I’ve read about FastFader library (which works with FastLED) but it appears to only work with digital strips (though my code skills are weak). Thanks.

Mark_Kriegsman · January 4, 2015, 3:17am

What setup do you already have?
You can definitely use FastLED to help write a color fade.
What’s the current hardware and software that you have running already?

Yannik_W · January 4, 2015, 3:52am

U could convert your starting hue and your goal hue to RGB with FastLED’s integrated libary hsv2rgb.h and then u could make a RGB fade. But im not sure whether FastLED is made for analog stripes…

Mark_Kriegsman · January 4, 2015, 3:54am

There’s even an example code included that shows how to do this.

github.com

FastLED/FastLED/blob/master/examples/AnalogOutput/AnalogOutput.ino

#include <FastLED.h>

// Example showing how to use FastLED color functions
// even when you're NOT using a "pixel-addressible" smart LED strip.
//
// This example is designed to control an "analog" RGB LED strip
// (or a single RGB LED) being driven by Arduino PWM output pins.
// So this code never calls FastLED.addLEDs() or FastLED.show().
//
// This example illustrates one way you can use just the portions 
// of FastLED that you need.  In this case, this code uses just the
// fast HSV color conversion code.
// 
// In this example, the RGB values are output on three separate
// 'analog' PWM pins, one for red, one for green, and one for blue.
 
#define REDPIN   5
#define GREENPIN 6
#define BLUEPIN  3

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Yannik_W · January 4, 2015, 3:56am

ok it is made for analog stripes too

Josh_I · January 4, 2015, 4:22am

Thanks All. I’ve been working off the analog example but am not clear on how to fade colors between the showAnalog command that aren’t next to each other on the hue spectrum/rainbow.

Current hw/sw: arduino / 5050 analog strip ?

Mark_Kriegsman · January 4, 2015, 4:38am

Check out the “blend” functions in colorutils:
https://github.com/FastLED/FastLED/blob/master/colorutils.h

You could set up your start color and end color, and then loop a variable from 0…255, calling
CRGB c = blend( start, end, loopvar);
and then just “analogShow” the blended color c.

If you use HSV colors, you get an HSV fade. If you use RGB colors, you get an RGB fade.

Try it; play around and see what you like.

Sky_Jones · January 4, 2015, 7:28am

One trick I use is the Noise + Palette code (found in the examples folder):

I create my own color palette of whatever colors I want (could be a short hue range), and then change the scale to 1. It just zooms right in, so the effect is just randomly cycling through whatever colors you chose in the palette.

Josh_Ingleby · March 2, 2016, 2:48pm

Thanks @Sky_Jones and @Mark_Kriegsman . The noise+palette and ColorUtils look to be great options.

I think my main issue is comprehending what changes in the addressable examples to simplify for analog strips. I’ve tried implementing below but not sure what to put within the showAnalogRGB.

http://pastebin.com/j2xuL6E2

In the setup what do I define the addLeds as for analog…or do I remove that completely and just change the FastLED.show() to showAnalogRGB(?) ?