The box works on these components:
Fatshark kompatible receiver
5V BEC system
12v 40mm fan (works on 5V)
On the internet you can find sketches describing the pin-output of the receiver:
You need 5V in, mass and video. It is handy to use a receiver that can be controlled "onboard".
The diversity cap can easily be remade by you for your custom receiver.
I used the 5,8GHz Realacc True-D Diversity receiver.