Hi everybody, I'm new to this forum and I hope I could be useful for this community. ;-)

I'm currently working on a led matrix projects with other people.
We have already a working prototype and I am developing a Java application to pilot the leds, that are in a RGBW led strip.
We initially started to develop our own software because existing programs such as Glediator or FastLed doesn't handle led strips with a white component, what becomes more and more common.

Finally, we have those RGBW led strips, we have an app to control the four components, but we don't know what to do with the last one, and it has to be there for something, and we would like to optimize this something!

So here is an open discussion : What is exactly the purpose of the white component?
Are they only here to provide a more simple way to display pure white, instead of doing R+G+B (that gives, it is true, a less pure white)?
Could they have a more general utility, in terms of other colors? Because finally, in an animation, pure white is quite unusual.

In Java, I'm using the Javafx 8 Color class that provides a simple way to switch from HSV color representation (that I am using to generate animations) to RGB representation (the only thing that leds understand).
Visually speaking, it seems that adding white is like increasing the "Value" component, or brightness. But this is easier and works perfectly with the RGB system, without the white led.
Could the fact that changing only one component (the white component) instead of the 3 others to generate the same color could be used to create a faster communication protocol between the program that generate the animations (that run on a computer, server or other) and the microcontrollers which transmit data to the leds? (currently, the program transmit all the 4*[number_of_leds] components at each frame to the microcontroller through USB or WiFi)
Could there be interests in terms of energy consumption?

Any idea is welcome!

Paul

BONUS : a picture of our led panel and screenshots of the app. ;-)

 

Welcome to AAC!

What is exactly the purpose of the white component?
Are they only here to provide a more simple way to display pure white, instead of doing R+G+B (that gives, it is true, a less pure white)?

The quality of white light created by RGB LEDs is usually inferior to the light from a white LED (which is probably an ultraviolet LED using phosphor in the lens to make white light).

 

Welcome to AAC!

The quality of white light created by RGB LEDs is usually inferior to the light from a white LED (which is probably an ultraviolet LED using phosphor in the lens to make white light).

OK, so here is an interest, when we want pure white. But as I said, finally (in my case at least, when each led color is always changing) using pure white is quite unusual. Could this pure white be mixed with other colors to enhance the color spectrum generated by the RGB components?

 

Could this pure white be mixed with other colors to enhance the color spectrum generated by the RGB components?

It will wash out the RGB components. If that's the effect you want, go for it.

 

I finally found those very interesting documents :
- http://blog.saikoled.com/post/44677718712/how-to-convert-from-hsi-to-rgb-white
- http://www.mirlab.org/conference_papers/International_Conference/ICASSP 2014/papers/p1214-lee.pdf
- http://web.archive.org/web/20101008153429/http://www.nouvoyance.com:80/files/pdf/Adding-a-White.pdf
They show several algorithms that can be used to convert a RGB/HSV represented color to a RGBW color, improving some brightness properties of saturated colors, reducing power consumption and making some colors more natural, especially pastel colors.

I think that was what I was looking for! Thank you for your answers!