Spysecurityshop.nl offers WiFi Digital door spy camera, intercom and 7 "color screen that wirelessly displays a message via Wi-Fi on your Android or Apple smartphone and your phone will ring when the doorbell you. 
See on your smartphone wherever you have internet access, anywhere in the world who is at the door and talk back. 
Digital Door Spy can also function besides as a doorbell and motion: someone comes then get a message around your doorbell.

specifications:

    Door Spy: go through your door
    7 "color display
    Wireless digital door spy camera and intercom for smartphones and tablets
    Take pictures and videos of who rings the doorbell
    Chime connect via WiFi
    Direct a call or push message through the free Android or iOS app
    Is powered by a rechargeable battery that lasts one month.
    With motion sensor: you will get an instant message as soon as someone comes close to the doorbell (can be put off)
    Multiple apps / users can receive calls when someone rings
    The call can be pressed away
    With infrared LEDs for night vision