Large Z568M nixie tube driven by a Nixie Badge Add-on and a ESP8266.
A python script counts the number of unread Telegram messages and sends an HTTP GET to the Nixie Notifier with the number desired.
The Nixie Notifier runs a webserver on the ESP8266 and receives requests through HTTP from anywhere on the LAN. The Nixie Badge Add-on boost 5V to 180V and via its I2C interface, takes care of the high voltage level shifting.
Alternating between two numbers makes it possible to count beyond 9: