
NodeMCU is a #WiFi module that allows us to connect to a network to transfer or exchange information online. It embeds an Esp8266 chip in it which is a WiFi microchip. Also, using messenger apps, the BOTs can be used for controlling a device.
In this article, we will explore how to connect the WiFi chip to a network and control the switching ON and OFF of an LED using the Telegram App. The control of LED is going to be done using the Arduino IDE.
Hardware List
The following components are used for building the circuit.

NodeMCU is a platform provided for #IoT. It basically includes firmware (computer software that contains instructions and controls the hardware) which runs on Esp8266 WiFi SoC (software on-chip). It is open-source firmware available for prototyping and developing kits. MCU means a Micro-Controller Unit. The device contains GPIO (General Purpose Input Output) pins which send and receives data on connection to other devices.
Esp12e module is also an SoC used for WiFi and is used in this project.
The specifications of the Esp12e module are:
32-bit lx106 RISC Microprocessor.
80MHz-160MHz, the adjustable clock frequency.
Supports Arctic OS(Operating System).
1 KB Internal #RAM.
4 MB External flash.
2.5V to 3.6V, 3.3V onboard.
600 milliAmp Regulator.
80 milliAmp Operating Current.
20 microAmp Current in sleeping Mode.
17 GPIO pins (which include ADC channels, 2 UART Interfaces, 4 PWM outputs, LED, Reset button, etc.).
Buy NodeMCU from here.
2. LED

Light Emitting Diode is a commonly used light source. It is a semiconductor that emits light when current flows through it.
Buy LED from here.
3. Breadboard