SystemsESP-WROOM-S2 is a Wi-Fi module with an ESP8266EX core manufactured by the Espressif Systems. It is a small, 16Mbit SPI Flash, Wi-Fi module that supports IEEE 802.11b/g/n. It comes in an SMD package that supports serial peripheral interface (SPI) mode operation. It features 16Mb of internal flash memory and has a power-saving mode that can be used to conserve energy using radio deep-sleep technology. It also includes support for an on-board antenna and is capable of high throughputs up to 150Mbps. This small, low-cost Wi-Fi module makes it suitable for a wide variety of Internet of Things (IoT) applications including home automation, security systems, wearables, and more. The available GPIOs for controlling various applications are: 3-I/O pins that can be used as general I/O, and one 4-bit ADC channel is also available.