Coding a slider as a linear on/off switch

Patterns and Code
1

Dear coders, i am looking for some help.
I tried to create a slider as a ‘runner-up’. (no leds when 0, all pixels on when 1)
But i kept on getting errors of all kind.
Someone has done this before?

The plan is to later replace the slider by an analog input from a potmeter.
Thanks

2

Hi,
If I understand correctly, you want to use a slider, and eventually a potentiometer to control how many of the LEDs are lit on a strip or other display. Here’s one way you might do that, based on the default “rainbow” pattern (the pattern you get when you press the “New Pattern” button.)

// start with all LEDs lit
var onPct = 1

export function sliderLightsOn(v) {
  onPct = v
}

export function beforeRender(delta) {
  t1 = time(.1)
}

export function render(index) {
  // calculate the position of the current LED as a percentage of the
  // total.   We'll use this to generate the rainbow color, and to 
  // determine which LEDs should be turned on.
  pct = index/pixelCount;
  
  // animated rainbow hue
  h = t1 + pct
  
  // LED will be lit if the current slider setting is greater than
  // the LED's % position in the strip.  Move the slider to change
  // the number of lit LEDs.
  hsv(h, 1, onPct > pct)
}
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3

Thanks a lot Zranger, works perfectly with great potential. I am building a tubular lamp that you can dim by rotating it. Now i can add a ‘linear’ dim. I will send video soon.

1 Like