Interval option?

I`m new on forum, so hello to all users:-)

I was searching but i cant find any information and i wonder if its possible to somehow (maybe other software?) set a intervals timer while song is playing eg 15sek/30sek.

I use basic sansa clip.

The only alternate firmware is Rockbox at

If you are using DRM material, like library audiobooks or subscription-service music, you take a risk instaling Rockbox.

Otherwise, if you are computer-friendly, give it a try. It’s not for people who don’t know a little about tech. 

It looks like they were talking about an interval timer but I don’t know if they ever made one.