LED Cross Fade

As I've been working on my computer meditation for() loop project, the next step was to get the LED colors to fade from one to the next, rather than snapping right from one color to the other. This seemed like it should be really simple, but it proved to be rather challenging. Getting each color of the RGB LED to transition simultaneously, and at a controllable speed was the tricky part. (getting them to transition one after another was not too hard).

I looked online and couldn't find much of use that was versatile enough, except for this Arduino example which frankly just seemed way more complicated than it needed to be. However, I was able to use it as a template to create a much more concise version that allows the user to input not only the starting and ending colors, but also the duration and smoothness of the fade. I hope this is helpful to anyone who might be looking for something similar...

(Scroll to the bottom of the post for code you can copy and paste. If that's not working for whatever reason, you can find it here)

In the mean time...

A nice little package fortuitously arrived at my doorstep yesterday

So... I upped my pushbutton prayer bead prototype (see my prior posts in the link above if that makes no sense to you) to include 5 buttons, confirming that the process used to coordinate 2 and 3 buttons will work indefinitely!

	/*////////////////////////////////////////////////////////////////
	LED CROSSFADE FUNCTION
	Requirements:
	• RGB LED Arduino circuit
	• Written for Processing's Arduino/Firmata library
	• Can be reconfigured for Arduino (without Firmata)
	by removing "arduino." before the "analogWrite" functions
	Syntax:
	LEDcrossFade(RedPin, GreenPin, BluePin,
	StartingR, StartingG, StartingB,
	DestinationR, DestinationG, DestinationB,
	Steps, Duration)
	Parameters:
	• Red/Green/BluePin - The pin numbers/variables associated with
	the RGB LED
	• StartingR/G/B - The RGB value you want to fade FROM
	• DestinationR/G/b - The RGB value you want to fade TO
	• Steps - Number of steps transition is broken into
	(higher the value, the smoother the fade)
	• Duration - Total duration of fade (in milliseconds)
	Example:
	"LEDcrossFade(9,10,11, 0,0,0, 255,255,255, 20,2000);"
	This will fade an RGB LED that's connected to pins 9, 10, and 11
	from off (0,0,0) to white (255,255,255) in 20 steps over 2 seconds
	/////////////////////////////////////////////////////////////////*/
	void LEDcrossFade(int RedPin, int GreenPin, int BluePin,
	int StartingR, int StartingG, int StartingB,
	int DestinationR, int DestinationG, int DestinationB,
	int Steps, int Duration) {
	// break fade into Steps to determine smoothness of the transition
	// and find the amount of change for each color, each step
	// in order to reach the destination in the given amount of steps
	float RchangePerStep = (DestinationR - StartingR)/Steps;
	float GchangePerStep = (DestinationG - StartingG)/Steps;
	float BchangePerStep = (DestinationB - StartingB)/Steps;
	// loop through each step, displaying each color, then
	// increment each color by the given amount of change per step
	// to prepare for the next step
	for (int i = 0; i < Steps; i++){
	arduino.analogWrite(RedPin, StartingR);
	arduino.analogWrite(GreenPin, StartingG);
	arduino.analogWrite(BluePin, StartingB);
	StartingR += RchangePerStep;
	StartingG += GchangePerStep;
	StartingB += BchangePerStep;
	// ensures that the last step brings the LED exactly to the
	// destination color, compensating for any messy fractions.
	if(i == Steps-1){
	arduino.analogWrite(RedPin, DestinationR);
	arduino.analogWrite(GreenPin, DestinationG);
	arduino.analogWrite(BluePin, DestinationB);
	}
	// delay each step long enough to reach the last step
	// by the desired duration
	delay(Duration/Steps);
	}
	}

view raw LEDcrossFade_Function hosted with ❤ by GitHub

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