A Queens basketball coach who sexually exploited teen boys was sentenced Thursday to at least 18 months in prison, authorities said.

Robert Walker, 43, of Jamaica told a 15-year-old boy to take naked pictures and pose for him using the video chat service OoVoo, according to Queens District Attorney Richard Brown.

Almost 30 pictures of kids between the ages of 8 and 13 performing sex acts with men were found on Walker's electronic devices, authorities said.

He admitted to investigators that he conducted workouts with teens younger than 16 and asked them to take off their clothes. He shot pictures and video of them.

A search warrant also showed that he manipulated three teen boys he coached into stripping naked on OoVoo, as well as once in person.

"The defendant took advantage of his trusted position as a basketball coach and violated the teen boys he instructed in a disgusting manner to satisfy his own sexual needs," Brown said. "The victims will undoubtedly be scarred for the rest of their lives as a result of this man's manipulative actions."

Walker, who on Aug. 4 pleaded guilty to disseminating indecent materials to minors, will serve between 18 months and 4 1/2 years in prison, Brown said. Walker will be required to register as a sex offender upon his release.