Let us have a look at ESP8266, a versatile low-cost WiFi microcontroller

ESP8266 is a microcontroller which integrates a Tensilica 32-bit processor. It is WiFi enabled and is a popular choice for the use of Internet of Things (IoT). ESP8266 is relatively inexpensive and is used in mobile devices and wearables because of the low power consumption. There are three modes of operation – active mode, sleep mode and deep sleep mode. This allows battery conservation.

Silicon Labs CP2102 integrated circuit is a USB-to-UART bridge, used to establish communication between a computer and ESP8266 microcontroller. UART stands for Universal Asynchronous Receiver/Transmitter.

1117-33 is a low-dropout linear regulator. It takes a higher input voltage like the 5V from a USB input and regulates it down to 3.3V.