Have run a small minecraft server for half a decade.
Designed a simple way to see if anyone was logged in so my boys could log on when people was on instead of using their play time sitting waiting....
This is version 2, with 3D printed enclosure.
This version also do not rely on server scripts. It connect to the server directly to get number of players and max number of players.
it also have a easy to use config - just connect to the AP it sets up (MCViser) , browse to 192.168.4.1, enter wifi credentials and witch server and server port you want to monitor.
in case of wrong settings push the button AFTER 2 seconds while the needle is doing its initial test sweep to reset settings. (if button is pressed during power on it will enter flash program state)
3.3V reg for the ESP module. Button between GPIO0 and GND Resistor between GPIO2 and the signal pin of the servo. Capacitors as needed. And pull up resistors also as needed.