introduction to nodemcu v3, nodemcu v3 features, nodemcu v3 pinout, nodemcu v3 applicationsHi Friends! Welcome you onboard. I am back to give you a daily dose of useful information. Today, I’ll unlock the detailed Introduction to NodeMCU V3. It is an open-source firmware and development kit that plays a vital role in designing your own IoT product using a few Lua script lines.

The module is mainly based on ESP8266 that is a low-cost Wi-Fi microchip incorporating both a full TCP/IP stack and microcontroller capability. It is introduced by manufacturer Espressif Systems – A manufacturer based in Shanghai, China.

Arduino Modules and Microcontrollers have always been a great choice to incorporate automation into the relevant project. But these modules come with a little drawback as they don’t feature a built-in WiFi capability, subsequently, we need to add external WiFi protocol into these devices to make them compatible with the internet channel.

This is where NodeMCU V3 comes handy that incorporates a built-in WiFi support, giving an easy pathway to design IoT applications as per your technical requirements.

In this post, I’ll try to cover brief details related to this WiFi Development Kit, its main features, pinout and everything you need to know about this module. Let’s get started.

Introduction to NodeMCU V3

NodeMCU V3 is an open-source firmware and development kit that plays a vital role in designing your own IoT product using a few Lua script lines.

Multiple GPIO pins on the board allow you to connect the board with other peripherals and are capable of generating PWM, I2C, SPI, and UART serial communications.

  • The interface of the module is mainly divided into two parts including both Firmware and Hardware where former runs on the ESP8266 Wi-Fi SoC and later is based on the ESP-12 module.

The firmware is based on Lua – A scripting language that is easy to learn, giving a simple programming environment layered with a fast scripting language that connects you with a well-known developer community.

introduction to nodemcu v3, nodemcu v3 features, nodemcu v3 pinout, nodemcu v3 applications
And open source firmware gives you the flexibility to edit, modify and rebuilt the existing module and keep changing the entire interface until you succeed in optimizing the module as per your requirements.

  • USB to UART converter is added on the module that helps in converting USB data to UART data which mainly understands the language of serial communication.

Instead of the regular USB port, MicroUSB port is included in the module that connects it with the computer for dual purposes: programming and powering up the board.

  • The board incorporates status LED that blinks and turns off immediately, giving you the current status of the module if it is running properly when connected with the computer.

The ability of module to establish a flawless WiFi connection between two channels makes it an ideal choice for incorporating it with other embedded devices like Raspberry Pi.

NodeMCU V3 Pinout

NodeMCU V3 comes with a number of GPIO Pins. Following figure shows the Pinout of the board.

introduction to nodemcu v3, nodemcu v3 features, nodemcu v3 pinout, nodemcu v3 applications

  • There is a candid difference between Vin and VU where former is the regulated voltage that may stand somewhere between 7 to 12 V while later is the power voltage for USB that must be kept around 5 V.

NodeMCU V3 Datasheet

  • You can download NodeMCU V3 datasheet by clicking the below button:
Download Introduction to NodeMCU V3

NodeMCU V3 Features

  • Open-source
  • Arduino-like hardware
  • Status LED
  • MicroUSB port
  • Reset/Flash buttons
  • Interactive and Programmable
  • Low cost
  • ESP8266 with inbuilt wifi
  • USB to UART converter
  • GPIO pins

As mentioned above, a cable supporting micro USB port is used to connect the board. As you connect the board with a computer, LED will flash. You may need some drivers to be installed on your computer if it fails to detect the NodeMCU board. You can download the driver from this page.

Note: We use Arduino IDE software for programming this module. It is important to note that the pin configuration appearing on the board is different from the configuration we use to program the board on the software i.e. when we write code for targeting pin 16 on the Arduino IDE, it will actually help is laying out the communication with the D0 pin on the module.

Following figure the shows the pin configuration to use in Arduino IDE.

introduction to nodemcu v3, nodemcu v3 features, nodemcu v3 pinout, nodemcu v3 applications

How to Power NodeMCU V3?

You can see from the pinout image above, there are five ground pins and three 3V3 pins on the board. The board can be powered up using the following three ways.

USB Power. It proves to an ideal choice for loading programs unless the project you aim to design requires separate interface i.e. disconnected from the computer.

Provide 3.3V. This is another great option to power up the module. If you have your own off-board regulator, you can generate an instant power source for your development kit.

Power Vin. This is a voltage regulator that comes with the ability to support up to 800 mA. It can handle somewhere between 7 to 12 V. You cannot power the devices operating at 3.3 V, as this regulator unable to generate as low as 3.3V.

NodeMCU V3 Projects and Applications

NodeMCU V3 is mainly used in the WiFi Applications which most of the other embedded modules fail to process unless incorporated with some external WiFi protocol. Following are some major applications used for NodeMCU V3.

  • Internet Smoked Alarm
  • VR Tracker
  • Octopod
  • Serial Port Monitor
  • ESP Lamp
  • Incubator Controller
  • IoT home automation
  • Security Alarms

That’s all for now. I hope I have given you something valuable related to this module. If you have any question, you can approach me in the comment section below. I’d love to help you the best way I can. You are most welcome to keep us updated with your valuable feedback so we keep producing quality content as per your needs and requirements. Thanks for reading the article.


  1. Hi mate, very good post! Excuse my english, I know it’s very bad.
    I am doing a project and I wanted to know if there is a library of this device for Proteus. In case the answer is yes, where can I find it?

    Thanks! Bye

  2. Hi, nice article! What is still unclear to me is how the various power-pins are connected. If you want to use them in a special way, it’s not really clear.
    Powering via the USB-plug is straight forward. The onboard regulator provides the 3.3V for the ESP. How is Vin connected? Directly to Vcc on the USB-plug? Via a diode? Is the USB-plug also connected via a diode to prevent current out of the USB-plug if powered via Vin? And how is VU connected? With or without diodes? To the USB-plug or to the input of the regulator?
    You see, it would be best to have the schematic of this board. Can you help with one?
    Regards, Karl

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