Commune with the waves and dolphins, sure. Isn’t that why people flock to the beach? But start a dialogue with 500 trash cans in the Santa Monica sand? A new campaign for environmental nonprofit Heal the Bay is trying to encourage tourists and locals to do just that, using their smartphones to read QR codes on the ad-wrapped cans. Once you do, you’ll find a mobile website with the latest weather, water quality, community Twitter updates and other pertinent sun-and-fun tidbits. This is after, presumably, you’ve absorbed the main message of the ads, which is, “Pick up that soda can, litterbug.” The campaign, from DDB L.A., also allows people to share their day-at-the-beach photos and sign up for Heal the Bay cleanup events. The ad agency’s executive creative director, Matt Reinhard, said he thinks trash cans are “an underutilized vehicle with great potential” and that QR technology can “stimulate a deeper conversation” with beachgoers. Can it remind them to use their sunscreen? That’s always helpful.