Hello everyone, I am trying to build out an idea here,

Nathan_Hejnicki · June 15, 2018, 2:01pm

Hello everyone,

I am trying to build out an idea here, and could really use some help knowing what function to call and the syntax around it.

Here’s what I’m going to do with this eventually:

I plan to use MOSFETS for each of the R, G, and B channels of a 4-pin LED strip (not individually addressable, just the IKEA Dioder lights) controlled via an Uno. I have a remote and IR sensor, and want to make it so I can configure the remote to trigger different “scenes.” For example, pressing button 1 would set the strip to red, button 2 would make it “breathe” from all the way off to fully Red, button 3 would do the same as button 2 but purple, and button 4 would crossfade the LEDs between purple and green. Each function would just repeat until a new button was pressed or the Arduino is unplugged.

To test out the base functionality while I wait on the FETs to be delivered, I am using just a single RGB LED and resistor type thing, with 3 pins connected to PWM slots on the board.

The question I have currently:
Is there a way to write a specific function to fade between two colors? Or even better, have a function that just looks at what the current color is, and then fades to an RGB value you pass it? For example, I have the LEDs set to a purple color. I call the function to have it change to teal rgb(0,127,128) and it smoothly fades over a time i’d set in ms from purple to “teal.” Then I can call the function again and have it fade to hot pink or something else. The color wouldn’t necessarily be one of the named colors in the FastLED library, though it sometimes would be.

I’ve messed around with the library as best I can, but I’m somewhat new to arduino and having trouble figuring out how to convert a lot of the examples i’m finding that seem to be for the individually addressable RGB strips, to a single LED strip (or at first, LED, until I put in the MOSFETs and have it control the whole strip)

If there is anyone that could help me by either pointing to a function of the library or possibly some code snippets for any or all of the above, I’d certainly be grateful.

Cheers,
Nathan

Jeremy_Spencer · June 15, 2018, 3:12pm

Did you find this?
It’s a good place to start…

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

This file has been truncated. show original

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

This file has been truncated. show original

Nathan_Hejnicki · June 15, 2018, 3:25pm

@Jeremy_Spencer I did find that and have it working perfectly on my board, I think the thing i’m having trouble with is how do I change what’s in the loop function there to be something more like “fade back and forth between these two specific RGB colors” instead of all through the 255 spectrum and back again? It seems like any “fading between colors” I am able to find all use the single digital LED pin instead of individual R, G, B pins, and most if not all of them seem to be for addressable LEDs and for the life of me I can’t seem to figure out how to convert that code from the things like what are in the DemoReel100 file to language that my simple dumb RGB light will understand, if that makes sense.

Jeremy_Spencer · June 16, 2018, 10:19am

Just use one led, it’s probably easiest to use HSV colours.