Yes, it is possible to build a video doorphone of your own and the best part is you can recycle an old android of yours. You can always find all apps required for this purpose in Playstore, the only thing you will need to build is a remote control and a screen that can display your picture over the door. Before moving ahead, take a look at how it works: https://www.youtube.com/watch?v=LUeTJg3IxO0

 

 

 

The raw materials required for this purpose are arduino/genuine MKR1000, Arduino UNO R3 Board, UNO R5 2.8 TFT Touch Screen along with SD card socket for an Arduino Board Module, a breadboard, a relay module of 10A, 5V and opto isolated; three smartphone power supplies, a USB extension cable, power plug for Arduino Uno, and a connector fitting with 5V power supply plug from any Windows mobile phone. 

 

Now the first thing you need to do is set up the breadboard with a MKR1000 and connect all parts with each other as depicted in the picture below. Now connect the power supply for Uno with the right relay module. The cathode line of power plug needs to be switched with relay, the anode line on the other hand, needs to be plugged in a 5V connector that comes from the Arduino board. The second relay module that switches the power supply with Android phone can be seen as follows. You can always cut open the USB extension cable for switching the anode line through the relay. Last, the MKR1000 needs to be flashed through a proper code to switch relay modules and assemble those as shown below: 

 

You can skip coding by choosing Windows Remote Arduino. All you need to do is flash the StandardFirmata from Arduino IDE for switching with StanrdardFirmataWiFi or USB to switch with network. With StandardFirmata you can get every kind of  from MKR1000 while with StandardFirmataWiFi you wouldn’t be able to gain anything from port 5,7,8,9, as well as 10. 

 

For other details, please refer to the link given below.