Help with led strip project

Hello, Need a bit of help with programming my led strip. I have a ws2811 strip with 300 leds, I need it to start running by the press of a button. The strip needs to turn on the three first leds and "wave" until the last led, then do that again (total of 12 seconds) Then another loop which turns on in red then delays for 500 ms and then purple for 500 ms and so on for the total of 15000 ms to finaly turn off and end the loop.

If someone did something similar please share your code.

You won't get your code that way and in fact even if you do, you won't be able to work it out. So, first of all play with your ws2811 LEDs along with Arduino, install its library, test out basic examples and the code you want to design doesn't seem to be much difficult. Design some code and then ask for help.

So you want to do this?

Repeat for 12 seconds: Turn off all LEDs Turn on 0, 1, and 2. (unspecified color) Turn off 0 and turn on 3. (unspecified color) Turn off 1 and turn on 4. (unspecified color) ... Turn off 295 and turn on 298. (unspecified color) Turn off 296 and turn on 299. (unspecified color)

Repeat for 15 seconds: Turn on all lights Red. Wait 500 milliseconds. Turn on all lights Purple Wait 500 milliseconds

If that is not what you want, what DO you want?