In this video I make a breakout board for the ESP-12 wifi module using a plywood jig, wires, solder, scrap PCB, header pins, and hot melt glue.
I hook up the right combination of pull up and pull down resistors, and demonstrate it turning an LED on and off in response to MQTT messages. I draw up a circuit diagram to show how things connect.
Along the way I discover that GPIO4 and GPIO5 are swapped on the silkscreen of the ESP-12 boards I bought.
The Lua code for controlling the LED using MQTT can be found here:
I used the Nodemcu Devkit v1.0 schematic diagram as my reference: