Tally Lights are used in the broadcasting world to let Camera Operators know when their feed is currently on Program or Preview, giving them a heads up on when they're On Air, or about to be (On ...
Arduino (support W5100 like must be set, and ENC28J60 via UIPEthernet), esp8266 (SPIFFS, LittleFS and SD) (core <=2.4.2 must be set) and esp32 (SPIFFS, LITTLEFS, Ffat and SD), Arduino WiFiNINA SAMD ...