If they won't follow a standard 'bot, I can suggest a few rigs we used to lure nightsuckers on Nifflheim-- I'll transmit you those schematics in a second. They mimic human galvanic response, body heat, carbon output...

[Where's the flatdisc he stores those things on really ought to organize his notes one of these days-- he starts to rummage, leaving the communicator on the desk to show a blank wall.]