I went on a bit of an odysee creating "smart" thermal printers this summer in an attempt to build something suitable for giving Bitcoin payment notifications to merchants.
I started with battery-powered Bluetooth-enabled printers but found that the ESP32 microcontroller I was working with had trouble connecting to both WiFi and Bluetooth at the same time.
I ended up going with another printer model that supported TTL serial connections and landed on the ESP32 C3 board which has a very small form factor and was able to squeeze inside the case that comes with the printer.
I started with battery-powered Bluetooth-enabled printers but found that the ESP32 microcontroller I was working with had trouble connecting to both WiFi and Bluetooth at the same time.
I ended up going with another printer model that supported TTL serial connections and landed on the ESP32 C3 board which has a very small form factor and was able to squeeze inside the case that comes with the printer.
Here's a video showing the end result: https://www.youtube.com/watch?v=JiGoOJZUrP8
Skip ahead to 2:40 if you don't want to hear me talk and just want to see the build video where I connect the ESP32 to the printer.