Here is an overview and pictures of my S800 which I have modified and installed open hd in.
I have installed a Matek f411-wing flight controller with Inav 3.0.2 installed.
Powering the open hd system I have a ubec from aliexpress Page Not Found - Aliexpress.com which is rated for 5amps. The adjustable side of it is not useful for openhd as bit is 1v steps. It is also much larger than I expected but does fit into the bay nicely.
The wifi adapter I am using is an rtl8812au chipset card from aliexpress
I have soldered to the pads under the metal shielding (removed with pliers) and have modified the case to enable better airflow (removed the case, did the work and then put it back in the case)
This wired to a Rapberry pi zero which is also powered via the ubec (bridged from the wifi card pads). Currently connected to the pi zero is a pi camera v2.1 with an imx219 manual lens module [AU$27.22 33% OFF]IMX219 Camera Module 60 degree FoV for RPi Camera V2 Driver Board Raspberry Pi 3 B+ Module Board from Electronic Components & Supplies on banggood
https://banggood.app.link/R2exs2s1Tjb
This are all installed in a nose that I designed and 3d printed. I designed the nose to fit the pi zero and also to be modular for the camera.
I am running this all on OpenHD 2.0.12b. My settings are somewhat optimised for short range flying. The camera settings are based on what Sebastian posted in the telegram chat a little while back. My settings can be found here https://drive.google.com/file/d/1OF8ckie5wxFyBxGhnMl_L7k7SUxrkjdT/view?usp=drivesdk