The Engineering Projects

Setup Arduino Environment for NodeMCU Programming

In the previous tutorial, we have discussed the basics of ESP8266 modules and have also had a look at the different WiFi modules based on ESP8266. In today's tutorial, we are going to set up Arduino Environment for NodeMCU Programming. Today we will prepare the development environment and build code to blink an LED and report status on the Serial Port (to validate the configuration). We will use the Arduino IDE for coding and the NodeMCU board (a module that works with an ESP8266). Simple integration. Zero hardware complexity.

The ESP8266 is an extremely robust and versatile microcontroller, which has proven to be a powerful tool in building Internet of Things solutions. What makes the ESP8266 such a popular tool is the perfect integration between a robust 32-bit processor and a fully functional WIFI module that already includes Internet Protocols.

A simple target, but the goal here is to prepare and test the development environment and introduce the programming mode.

Material

• 1x Computer/notebook with the minimum requirements to install Arduino IDE;
• 1x Mini-USB cable;
• 1x NodeMCU

Arduino IDE Install

•  Our first step is to download the Arduino IDE installer. It is available at this URL (https://www.arduino.cc/en/software).
• Figure 2 shows the latest stable version 1.8.15.
• It is recommended that you always have the most current version.
• So, if there’s a newer version when you download it, it’s the right for you. The Arduino community provides constant improvements to the IDE.

• On the right side, you can find the correct version for each Operating System and download the correct installer.
• We will not go into details here about how to install from the file. The Arduino page itself features an excellent manual on Getting Started.

• If this is your first contact with Arduino, I recommend checking out the Learn Arduino section as well.

Arduino IDE Presentation

• So, IDE installed, let's get to know the interface before making some important settings.
• If everything is ok, you should get the following result when running Arduino.

 

Text Editor

• The first thing that should catch your attention is that the code has already started with two functions.
• The “void setup()” and the “void loop()”.
• Arduino maintains a bootloader in the microcontroller, which is an initiator program responsible for preparing the hardware for correct operation.
• When we turn the module on power or press the reset button, the bootloader is the first program to run.

One of the bootloader's main responsibilities is to receive the code we send and write it to the microcontroller's memory. And when the code plays, the bootloader asks two questions:

1– What do I do first?

Answer: What does the “setup()” function say to do.

2– What do I do after “setup()”?

Answer: Repeatedly execute whatever the “loop()” function tells you to do.

• By default, we use the “setup()” function to inform whether a pin will operate as input or output, set the initial state of each pin used, set serial port Baud Rate, initialize additional configuration functions.

Verify and Upload Buttons

• Once our code is done, we need to check if everything is right and write the code in the microcontroller.
• The check button does a code check to identify syntax or library integration errors. Attention: logic errors are not checked; these are up to the programmer.
• The Upload button also performs the verification and then sends the code to the microcontroller via the Serial port.

Feedback Interface

• Perhaps the most important snippet of the IDE, here it reports the status of testing and recording. This is where you see if everything is ok.

Serial Monitor

• The Arduino IDE has a tool called Serial Monitor that allows direct communication with the microcontroller from the Serial port.
• It is possible to follow what is being sent by the module and send commands directly to it.

Two points of attention

1. The Communication Port (in the example COM3) must be selected in the Tools
2. The Baud Rate (in this case, 115200) must be entered correctly, otherwise, the data may become illegible or simply not appear.
3. Baud Rate can be set in the “setup()” function when preparing the recording

Boards Manager

• Each Arduino module has its peculiarities. Amount of memory, available pins, etc.
• Just as important as making a well-built code is telling the IDE which card model will be used.
• IDE Arduino already brings in its basic installation, the installation of boards that use ATMEGA microcontrollers.
• If you are going to use another type of board, it needs to be installed in Boards Manager (tools -> Boards Manager...).

•  Once installed, the board will be available and must be selected from the Tools -> Board menu.

Attention point

• Until Arduino version 1.8.15, modules using the ESP8266 do not appear available in Boards Manager.
• This is because it is not yet included in the official Arduino repository.
• For it to appear, it is necessary to add the path of a new repository.
• Do this by going to the File -> preferences menu and add http://arduino.esp8266.com/stable/package_esp8266com_index.json in the Additional Boards Manager URLs field.
• Press OK, close Arduino, and open it again.
• In Boards Manager the ESP8266 option will be available. Click install.

Once this step is completed, the main modules using the ESP8266 will be available. For our application, we will use nodeMCU 1.0.

Coding NodeMCU with Arduino IDE

• After choosing the board, choosing the port (note, the port will only appear when you connect the board to the USB), it's time to make our first code.
• The nodeMCU Module has a built-in LED and we will make it blink every 1 second.

• For this sketch, we don't need to include any additional libraries.
• When we inform Arduino that we are using the NodeMCU board, it already knows who the LED_BUILTIN is and which pin it is connected to.
• We use #define LED LED_BUILTIN just to give a more practical name to our LED, it could be used to name an external pin, for example, #define LED 13, alternatively, the original name could be used in the code.
• pinMode(LED, OUTPUT) and pinMode(13, OUTPUT) would have the same effect.
• The pinMode(LED, OUTPUT), by the way, is used to inform that this pin will operate as output. Note that this configuration was done inside the setup() function, so the pin will be prepared before being used in another function.
• Serial.begin(115200) initializes communication with the serial port at baud rate 115200. In our Loop function we will follow the sequence:
• Turn off the LED, write the pin status to the serial, wait for 1 second, turn the LED on, write the pin reading to the serial, wait for 1 second and start all over again.
• Here's the video demonstration of LED Blinking with NodeMCU:

So, that was all for today. I hope you guys have enjoyed today's tutorial on LED Blinking with NodeMCU. In the next tutorial, we will have a look at How to connect NodeMCU with webserver. Stay Tunned. Thanks !!! :)

ESP8266 based WiFi Modules for IoT Projects

The Internet of Things (IoT) and the Industry 4.0. Distinct technological revolutions but with a common goal: To integrate equipment (digital or analog) to a computer network.

And to be part of this revolution, the developer goes out of its way to include wired ethernet modules or WIFI modules in its circuits. Which increases complexity, circuit size and development cost.

What if I told you that already has a built-in WIFI microcontroller? And that it fits in the palm of your hand? For just 1 US dollar?

Today I’m going to introduce you to the ESP8266 microcontroller, from Espressif. And for those of you who already program in 8Bit microcontrollers like the Atmega328 (one of the most common on Arduino) and struggle to build your code in the modic SRAM’s 2KB and Flash memory’s 32KB… The ESP8266 offers 32KB to RAM and 512KB to Flash Memory … expandable up to 4MB.

 Did I get your attention? So, let’s go to a summary of the specs, provided by the manufacturer itself:

• 32-bit RISC architecture;
• 80MHz processor (can be expanded up to 160MHz);
• Operating Voltage of 3V;
• 32KB of RAM memory for instructions;
• 96KB of RAM memory for data;
• 64KB of ROM memory to boot;
• Flash memory preview by SPI (512KB to 4MB);
• Wireless 11 b/g/n standard;
• Operating modes: STA/AP/STA+AP;
• WEP, WPA, TKIP, AES security;
• Built-in TCP/IP protocol;
• QFN encapsulation with 32 pins;
• Main Peripherals: UART, GPIO, I2C, I2S, SDIO, PWM, ADC and SPI;
• Architecture with prediction of operation in energy saving

At this point you may have noticed that I stated that the ESP8266 has a 512KB Flash memory, extendable up to 4MB, but then I said that the module only provides this memory per SPI. Before explaining this, I want to draw your attention to another important point: The ESP8266 has a WIFI module inside a QFN package. WIFI is radio frequency! And how does it work without an antenna? The answer is: It doesn’t work!

The ESP8266Ex chip (this is its full name) needs an antenna to be connected to your antenna’s specific pins as well as a FLASH memory IC.

Started to get complicated? Don’t worry. With the idea of making the chip more accessible, several modules were developed that already include an antenna and a memory chip.

Understanding the need to include an antenna for the WIFI, a memory IC in the SPI and making pins more accessible, several manufacturers started working on ore “friendly” ESP8266’s versions. Among the best known are the ESP-01, ESP-03, ESP-05, ESP-07, ESP-12E, ESP-12F and NodeMCU. All of them have the esp8266 microcontroller in common, but they vary in size, antenna availability, memory size and pin availability. There are others, but today we’ll talk a little about them.

Where To Buy?
No.	Components	Distributor	Link To Buy
1	ESP8266	Amazon	Buy Now

ESP-01

It is the most common module in the ESP8266 range. It is compact (24.8 x 14.3 mm), the WIFI antenna is built in the board itself and has two GPIO pins that can be controlled according to programming. There are two significant drawbacks to this card:

• The pins are not intended for connection to a breadboard. Although they fit well, they end up shorting So, they necessarily need wires to extend the pins.
• The two available GPIOs play an important role in the board So it is necessary to pay attention to the level (high/low) when the board is initialized, or the board may mistakenly enter in programming mode. So, pins are safer operating as Outputs than as Inputs.

ESP-03

 

This version comes with a ceramic antenna, 7 GPIOs (two are those of the ESP-01 that require attention), a pair for UART, in size 17.4 x 12.2 mm. Smaller than 01? Yes! But that comes at a price: The encapsulation is another.

ESP-05

• No GPIOs available, it actually doesn’t even have a built-in antenna.
• This version was thought to incorporate WIFI to some other microcontroller (with the smallest possible size: 14.2 x 14.2 mm), so it has an external connector and UART pins to be manipulated by AT commands.

ESP-07

• The ESP-07 has both a ceramic antenna and an external connector. Looks a lot like the ESP-03, but leaves the meager analog pin available.
• In addition to incorporating a metallic cover that protects the circuit against magnetic interference.

ESP-12E and ESP-12F

Built-in antenna, 11 GPIOs, UART available, SPI available (not exactly, it’s still being used by the flash memory CI, but now you get the option to disable the memory and associate a larger one), an ADC pin (pause here to explain because it’s not that useful, The board operates with 3.3V, but the ADC is 0 – 1V. Low resolution, plus the big risk of damaging everything.).

The ESP-12E would be icing on the cake for the ESP8266’s boards, but the ESP-12F version handled an improvement in the antenna design and a little more pin protection.

NodeMCU

The NodeMCU module is to the ESP-12s as the Arduino UNO is to ATMEGA328s. A board with a protoboard compatible pinbus, all ESP-12 pins available, a 3.3V regulator to power the module (the VIN pin can receive 5V) and a UART – USB interface that turn the nodeMCU into a plug an play module.

There are versions with the ESP-12E (increasingly rare) and with the ESP-12F.

Now that we know a little more about the hardware, let’s take a look at how to program it.

There are different ways to programming the ESP8266. Different methods, different languages, among the most common, we have the ESP-IDF (manufacturer’s official. C programming) and others recommended, also, by the manufacturer: NodeMCU (Lua Script), Arduino (C++), MicroPython (you get one candy if you guess the language). It is possible to work with it in PlatformIO as well.

ESP-IDF

The ESP-IDF is the official Espressif solution. The SDK has a number of precompiled libraries and works with the Xtensa GCC compiler.

For a long time, the company has released RTOS and NON-OS versions in parallel. But since 2020 no NON-OS versions have been released (except minor bug fixes). Other modules from Espressif were born exclusive to RTOS versions, probably this was already part of the decision to bury the NON-OS. IN 2019, the company released a note stating that it would keep the main version, but that it would only operate in the correction of critical bugs. It even released some new features after that, but it doesn’t compare in quantity to the RTOS version.

This is without any doubt the most specialized tool that allows for the greatest customization at a low level. Drivers and libraries are customized for company modules. And specialization directly reflects on performance.

But the ESP-IDF lacks in complexity and size of the active community. Which ends up making the solution’s development a little slower. How does this happen? The programming is done in C- ANSI, in some cases with the directly treatment of registers, creating a more verbose code. More verbose? More chances for bugs. Also, active community is something that needs to be looked at when using any technology. Whether for creating new libraries or for sharing issues and solutions. The ESP-IDF user community exists, but it is much smaller than the others that will be presented here.

NodeMCU

The NodeMCU is an ambiguous term, it can either be used to indicate the NodeMCU module (hardware) or the NodeMCU development environment (software), both can be used together. But not necessarily. Let’s go to the software one.

The NodeMCU is a Lua-based firmware specific to the ESP8266 and uses a SPIFF (SPI Flash File System) based file system. This firmware is installed directly in FLASH memory, which allows the code’s execution in real time, without the need for compilation.

It offers a library structure for native functionality and for sensor’s integration, such DS18B20 or BME280, which make programming more dynamic.

The NodeMCU has been popular for quite some time. But it has three serious problems that have started to reduce its use.

• The Firmware NodeMCU, installed in FLASH, takes up a lot of Especially if the full version is included.
• It was developed based on the NON-OS version, so, firmware bugs started to get more complex to
• The memory management is quite complex in some cases. Because it didn’t compile, some memory overflow issues could only be noticed at runtime. (This was the reason I stopped using this method).

Arduino

The Arduino platform, undoubtedly the best known in the world when it comes to microcontrollers, is also on the manufacturer’s list of nominees.

The Arduino was built as software-hardware relationship that makes microcontroller’s development more accessible to non-specialists. The hardware complexity was minimal (in some cases none) and the software started to be treated in a high-level language (C++), allowing even object orientation.

Because it is so accessible, some members of the software’s community have started to be collaborators in building libraries (Only to control LCD displays, I know four), some sensor’s manufacturers offer official versions as well. Constantly updated material. Etc. Etc.

The Arduino architecture started with the Arduino Uno board (which uses an ATMEGA328), expanded support to other boards and… for some time now, it has support for ESP8266 in different modalities. There is good compatibility with standard Arduino libraries and it has its own.

MicroPython

I Don’t know the MicroPython in practice (yet), but as the name advertises, it allows programming in Python. Like NodeMcu, it deploys a firmware to FLASH memory and has well- defined libraries for hardware usage.

The space occupied in Flash is well optimized (not even compared to NodeMCU chaos). It seams to have a very active community. As for programming complexity I don’t have much information. But if you program in Python, I think it’s worth the experience.

PlatformIO

The PlatformIO is not really a development platform, but it allows an integration with other platforms to simulate the board. If you don’t have an ESP8266 on dang yet, it might be a good choice for your first steps.

However, there is a natural limitation when simulating a module whose flagship is WIFI.

Don’t you know where to start?

Personally, I think that the Arduino environment is perfect for prototyping. It’s easy to get results pretty quickly to validate a proof of concept. But in some cases you can go beyond that. If your project doesn’t demand maximum performance from the ESP8266, even the production version can be built here.

For a project that requires a lot of hardware precision, I don’t recommend intermediaries. Nothing will perform better than IDF.

For educational purposes, our next articles will use the NodeMCU board programmed on the Arduino platform.