Video Diversity - without RSSI
This this system monitors and compares the video quality of 3 composite video signals, and switches to the "best" one. This is an Arduino code for a Wemos D1 board (ESP8266 chip), coupled to 3 LM1881 video sync separators, and a MAX4545 video switch.
Dedicated discussion thread, with schematics on RC Groups: https://www.rcgroups.com/forums/showthread.php?2839781-3-channel-DIY-video-diversity-system-for-FPV-%2Awithout-RSSI%2A