How to run a sketch for a fixed amount of time from power-on

[yelostoner]

Hello all, I'm relatively new to Arduino programming and need just a little bit of help figuring an issue out: I'd like to make the following sketch (which blinks a set of Neopixels red rapidly for a fixed amount of time) run for 2 second after the Nano it is running on powers up, OR - since the blink time length is 2000ms anyway - how can I loop the sketch only once? I've tried several ideas without luck so if anyone can help I'd be very appreciative!

#include <WS2812FX.h>

#define LED_COUNT 18
#define LED_PIN 4

WS2812FX ws2812fx = WS2812FX(LED_COUNT, LED_PIN, NEO_GRB + NEO_KHZ800);

void setup() {
ws2812fx.init();
ws2812fx.setBrightness(255);
ws2812fx.setSpeed(2000);
ws2812fx.setMode(FX_MODE_MULTI_STROBE);
ws2812fx.start();
}

void loop() {
ws2812fx.service();
}

[hammy]

Loop runs all the time , setup only once .

If you want the sketch to only run once , you can put it all in setup()

[Paul_KD7HB]

Explain what happens when the time is up. An Arduino never stops your loop() part of your code.
Paul

[yelostoner]

the strip will blink rapidly for 2 seconds, pause for 1 second and the repeat. I tried putting ws2812fx.service into setup and still runs more than once.

[hammy]

You need to look more closely at how this library works. I’m not familiar with it , I’m guessing there must be another command you can send, afterwards, to stop the lights

[yelostoner]

I'm happy to accept another solution that will create the same effect! this is being used as a third brake light on a childs go-kart so the solution doesn't need to be pretty. all I want to happen is for the strip to blink for two seconds rapidly when power is applied to the Nano

[hammy]

It appears you send a command and the leds flash with the setting you have sent and carry on until you send another command . There must be a command to send to blank the leds out .
Have you looked through the library documents and provided examples

Docs