Queuing system for a food service outlet

A system consisting of WiFi displays showing the order number and announcing the number vocally with a notification sound.
The displays are based on ESP8266 and receive orders via HTTP/UDP/MQTT.
The sound is transmitted via the i2s protocol to the DAC chip

An system controller to push numbers is embedded Linux based on the Onion Omega2 device
or a PC application (C++ Qt) is used to assign numbers