iOS: Best way to indicate popover?

I'm working on a simple music app for a client. There's a switch that triggers a backing track/beat that users can play sounds over that looks like this (the client insisted on the flower icon, don't judge):

Users are supposed to be able to choose between various beat patterns. I'm thinking about using a popover to allow users to change their beat pattern, but I'm not sure what the best way to indicate the popover is.

I've considered the detail disclosure button, but are there any ideas on better ways to either trigger a popover or allow a user to change the beat pattern?