Add special pin address to control main RGB

[Resseguie]

I'd like to be able to control the main RGB on the Spark. The Spark core firmware provides an RGB class for this but it doesn't seem to be mapped to a pin.

Could we assign a special pin address (255?) that is mapped to the RGB behind the scenes in voodoospark?

My use case: I just want to be able to turn it off once I connect using spark-io because I'm physically embedding the Spark with a standard RGB inside a little light (think mood light) and the flashing cyan overpowers the colors I'm setting.

[rwaldron]

RGBClass methods:

• control(true) could be mapped pinMode(255, OUTPUT)
• control(false) could be mapped pinMode(255, INPUT)? Not sure
• color(r, g, b) could be mapped to analogWrite(???)? Not sure
• brightness(0-100) no thoughts yet.

This is really messy.

[Resseguie]

I wonder how they actually handle brightness, since just dimming it can actually change the color if you aren't careful. I'll have to re-load the standard firmware and test it.

(That's exactly why I took it out of Johnny-Five's Led.RGB class for now until I figure out the best way to calculate it.)

[rwaldron]

I wonder how they actually handle brightness, since just dimming it can actually change the color if you aren't careful. I'll have to re-load the standard firmware and test it.

I'm curious to know this as well, unfortunately all signs lead back to LED_SetBrightness which apparently has no definition anywhere in that repo :(

[rwaldron]

Based on your tweet we could start simple by mapping board.digitalWrite(255, 1|0) to on and off

[canda]

@Resseguie thanks for the link, I didn't see this ticket. Brightness may be handled just lowering the numbers of red green and blue proportionally.

rgb(255,255,255) => white (1/full bright)
rgb(128,128,128) => grey (0.5/half bright)
rgb(0,0,0) => black (0/null bright)

rgb(255,0,0)=>bright red (1/full bright)
rgb(128,0,0)=>dark red (0.5/half bright)
rgb(0,0,0) => black (0/null bright)

And so on

I don't know if it is the best implementation, but the quickest I found to get to the point. I posted a pull request.

I have tested through the spark-io library and worked for me

[canda]

I selected the first byte arbitrarily. But i saw there was a gap defined in the array of first bytes. Does it have any special reason?

[Resseguie]

@canda reducing brightness by lowering RGB values proportionally "kinda" works. Those examples you provided are for pure colors. The difficulty is in mixed values.

[canda]

@Resseguie you need multiply each color value by a factor Lets say you have this strange brown color

rgb(190,155,123) => http://www.color-hex.com/color/be9b7b

And you want to make it 52% darker, then the factor would be 0.48 190 x 0.48 = 91 155 x 0.48 = 74 123 x 0.48 = 59

so we got a darker shade of the same brown

rgb(91,74,59) => http://www.color-hex.com/color/5b4a3b

[Resseguie]

Fixed by #40 and related spark-io additions.