Thanks that's it.I thought he was talking about this...
Amazon.com: Aputure Pro Coworker Wireless Remote RF Radio Shutter Release for Nikon D600 D5100 D3100 D7000 D5000 D90: Camera & Photo
that doesn't use WiFi... It uses IR (infrared)... which is line-of-sight... and is dodgey in bright light situations...