A man who thought he was chatting online to young girls was caught in a sting operation by a vigilante group.
Toni Stevens, 33, of Hele Road, Torquay, admitted sexual communication with a child and attempting to cause a child to look at an indecent image.
Exeter Crown Court heard the charity worker believed he was contacting 14-year-old girls in online chat rooms.
He was remanded in custody by Recorder Jonathan Barnes and will be sentenced next month.
The vigilante group Plymouth Against Paedophiles ran the operation, the court was told.
Stevens tried to contact 39 girls online. Members of the vigilante group posed as underage girls and responded to his online grooming in which he allegedly sent indecent images and suggested sexual contact, the court heard.
The police were called after members of the Plymouth-based group went to confront him at his home in Torquay on 27 November.