In Circuit Programming is still my favorite, and you only need 4 pins (3.3V, TX, RX and GND), ... In my Luddite world, I never HAD a development board for the ESP8266.

Calculator hacks have been around for a while now and we have seen the most action around the Texas Instruments TI-83 and TI-84. When [johnkimdinh] found a way to add an ESP8266 to a scientific cal… ...