A printed circuit board, or PCB, is used to mechanically support and electrically connect electronic components using conductive pathways, tracks or signal traces etched from copper sheets laminated onto a non-conductive substrate. wikipedia.org

"In electronic systems and computing, firmware is "the combination of a hardware device, e.g. an integrated circuit, and computer instructions and data that reside as read only software on that device" wikipedia.org

An embedded system is a computer system designed for specific control functions within a larger system. often with real-time computing constraints. It is embedded as part of a complete device often including hardware and mechanical parts. wikipedia.org

Embedded C is a set of language extensions for the C Programming language by the C Standards committee to address commonality issues that exist between C extensions for different embedded systems. wikipedia.org

Arduino is a popular open-source single-board microcontroller, descendant of the open-source Wiring platform, designed to make the process of using electronics in multidisciplinary projects more accessible. wikipedia.org

A microcontroller is a small computer on a single integrated circuit containing a processor core, memory, and programmable input/output peripherals. wikipedia.org

The ESP8266 is a low-cost Wi-Fi chip with full TCP/IP stack and MCU (Micro Controller Unit) capability. wikipedia.org

The internet of things (IoT) is the network of physical devices, vehicles, buildings and other items. It is embedded with electronics, software, sensors, and network connectivity that enables these objects to collect and exchange data. wikipedia.org

An electrical drawing, is a type of technical drawing that shows information about power, lighting, and communication for an engineering or architectural project. wikipedia.org