Measuring 25mm x 15mm, this tiny board pack quite a punch in terms of features. Made by espressif, this device have become very popular with engineers and hobbyist all over the world.

There are many varieties of the ESP8266, I bought the cheapest of the lot for only $3.08 each from ebay with free shipping.

Received the ESP-01 after about 2 weeks wait and I eagerly tested it by loading nodemcu on to it and runing the code below, it logged on to my AP with ease.

    ip = wifi.sta.getip()
    print(ip)
    --nil
    wifi.setmode(wifi.STATION)
    wifi.sta.config("SSID","password")
    ip = wifi.sta.getip()
    print(ip)
    --192.168.1.128