I am trying to emulate a rotating beacon using a Neopixel ring,

I am trying to emulate a rotating beacon using a Neopixel ring, but I cannot seem to get the fadeToBlackBy command to do anything but dim the led by the amount placed in the brackets. It never goes to black.
leds[0].fadeToBlackBy( 64 );
FastLED.show(); only dims the led.
Help is greatly appreciated.

Also, if you know a sketch that emulates a slowly revolving beacon, I would greatly appreciate knowing about it!


That should work, can you post the rest of your code at http://pastebin.com ? Are you setting that LED to a color elsewhere in the loop?

Are you possibly only calling fadeToBlackBy() only once? You need to keep calling it, as in a loop; each time it will dim slightly, until eventually it goes black.

Ah! No I am not doing it in a loop. Thanks for shedding light (or dimming light) on the problem.

Hi @F_Peter_Rohrmayer_II I just put a few sketches together you might like

Also try this one:
void cont_sinelon() // changing colors in continous circle
if (idex >= LED_COUNT) {idex = 0;}
for(int i = 0; i < LED_COUNT; i++ ) {
fadeToBlackBy( leds, LED_COUNT, 1); // 10 = long trail, 1 = short trail
leds[idex] += CHSV( gHue, 255, 192); }


Juergen, thank you very much! I may be able to use some of those in the future. The sinelon is getting close to what I want, but it is not there, yet. I am trying to emulate the rotating beacon in a lighthouse. The sinelon has the trailing leds dimming, but what I am trying to do is to have led(1) fade up(?) to full brightness, then dim as led(2) increases to full brightness. Then led(2) fades as led(3) increases, etc.
Thanks for your help. I know that I will be using some of your lines of code in the future.

Hi @F_Peter_Rohrmayer_II ‚Äč have a look at using a custom palette. It will probably do exactly what you want.

How many LEDs on that ring?

@Stuart_Taylor There are 12 less on the ring. Thanks!

I made two version, setup for 12 pixel Neopixel ring. The second one is based on @Mark_Kriegsman anti-aliased bar example. There are a few variables to play with and direction can be changed by using a negative delta value.
http://pastebin.com/D7LvW5gy (anti-aliased version)