Category Archives: Embedded

Embedded Protocol – CAN

CAN, short for Controller Area Network, was developed by Robert Bosch. This protocol facilitates half-duplex communication. In active voice, it would be: “It operates as a multi-master protocol, allowing it to connect multiple nodes.” This protocol utilizes a two-wire configuration, consisting of CAN H (H-High) and CAN L (L-Low). In active voice, it would be: This two-wire bus interconnects all nodes within the network. The wires typically constitute a twisted pair with a nominal impedance of 120 Ω. CAN supports communication over relatively short distances, typically up to 40 meters at speeds of 1 Mbps

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ESP32 NodeMCU Module – WiFi

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ESP8266 Arduino-Core Cayenne – Get Start with Cayenne MyDevice

What is Cayenne MyDevice?

myDevices Cayenne allows you to quickly design, prototype, and visualize IoT solutions. You can use Cayenne as a tool to visualize real-time and historical data, sent over to The Things Network. Let’s discuss “ESP8266 Arduino-Core Cayenne – Get Start with Cayenne MyDevice“

Cayenne is a platform for building IoT (Internet of Things) projects that provides tools for creating dashboards, monitoring devices, and controlling connected devices remotely. The Cayenne platform supports various microcontrollers and single-board computers, including the ESP8266, through the use of Cayenne MQTT or Cayenne MQTT API.

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Embedded Sensor – BMP280

Bosch Sensortec developed the BMP280 as a barometric pressure sensor. It’s designed with high accuracy and precision to measure atmospheric pressure and temperature. The sensor is commonly used in various applications such as weather stations, altitude measurement, indoor navigation, and IoT (Internet of Things) devices.

The BMP280 sensor utilizes a MEMS (Micro-Electro-Mechanical Systems) pressure sensor to detect atmospheric pressure changes. Additionally, an integrated temperature sensor provides temperature measurements. These measurements enable the calculation of altitude and provide data for weather forecasting, environmental monitoring, and other applications.

This sensor communicates with microcontrollers or other devices via standard interfaces like I2C (Inter-Integrated Circuit) or SPI (Serial Peripheral Interface). Consequently, it’s easy to integrate into a wide range of electronic systems.

Where Buy this Sensor

Ebay
Amazon
Aliexpress

Data Sheet

BMP280 Pressure Sensor

Suggest to study

ESP8266 NodeMCU – Pressure Measurement using BMP280 Sensor

Uses

The BMP280 sensor finds applications in various fields due to its ability to measure barometric pressure and temperature accurately. Consequently, here are some common uses:

Weather Stations: These stations often employ this sensor to monitor atmospheric pressure and temperature, providing data for weather forecasting and analysis.
Altitude Measurement: Altimeters use it to determine altitude above sea level by measuring changes in atmospheric pressure with elevation.
Indoor Navigation: In combination with other sensors, this device contributes to indoor navigation systems by providing altitude and temperature data for positioning and orientation.
Drones and UAVs: These unmanned aerial vehicles (UAVs) use the BMP280 for altitude control and navigation, enabling precise altitude hold and flight stabilization.
Environmental Monitoring: Environmental monitoring systems use the sensor to measure atmospheric conditions in indoor and outdoor environments, including air quality assessment and pollution monitoring.
IoT (Internet of Things) Devices: Various applications integrate the BMP280 into IoT devices, including smart home automation, agricultural monitoring, and industrial control systems.
Automotive Applications: In automotive applications, the BMP280 can monitor cabin pressure, compensate for altitude in navigation systems, and control climate.

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ESP32 NodeMCU Module – I2C Interface

The ESP32 NodeMCU module supports the I2C (Inter-Integrated Circuit) communication protocol. With its built-in hardware support for I2C, the ESP32 NodeMCU module can easily interface with various I2C devices such as sensors, displays, and other peripherals. This allows for efficient data exchange between the ESP32 and I2C devices, enabling a wide range of applications in IoT, robotics, automation, and more.

Embedded Protocol I2C : https://aruneworld.com/embedded/embedded-protocol/i2c/

ESP32 NodeMCU Module I2C Functions

Function	Description
i2c.address()	Send (SW) or queue (HWx) I²C address and read/write mode for the next transfer.
i2c.read()	Read (SW) or queue (HWx) data for a variable number of bytes.
i2c.setup()	Initialize the I²C interface for master mode.
i2c.start()	Send (SW) or queue (HWx) an I²C start condition.
i2c.stop()	Send (SW) or queue (HWx) an I²C stop condition.
i2c.transfer()	Starts a transfer for the specified hardware module.
i2c.write()	Write (SW) or queue (HWx) data to the I²C bus.
i2c.slave.on()	Registers or unregisters an event callback handler.
i2c.slave.setup()	Initialize the I²C interface for slave mode.
i2c.slave.send()	Writes send data for the master into the transmit buffer.

Code of ESP32 I2C Scanner

In this code used to can the i2c Devices
Used Software i2c and GPIO-23 as SDA and GPIO-22 as SCL of I2C Device
Connected DS3231 Device and check i2c address of DS3231

-- setup
id  =   i2c.SW                      --  Software
pinSDA  =   23                      --  1~12, IO index
pinSCL  =   22                      --  1~12, IO index
speed   =   i2c.SLOW                    --  only i2c.SLOW supported

--Initialize
i2c.setup(id, pinSDA, pinSCL, speed)                --  Initialize the I²C module.

print("Scanning Started....")
for count = 0,127 do
  i2c.start(id)                         --  Send an I²C start condition.
  Status = i2c.address(id, count, i2c.TRANSMITTER)      --  Setup I²C address and read/write mode for the next transfer.
  i2c.stop(id)                          --  Send an I²C stop condition.
    if Status == true then
        print("Addrss - "..count.." Detected device address is  0x" .. string.format("%02x", count) .. " (" .. count ..")") 
    elseif Status == false then
        print("Addrss - "..count.." nil") 
    end
end
print("Scanning End")

Results

Scanning Started....
Addrss - 0 nil
Addrss - 1 nil
Addrss - 2 nil
Addrss - 3 nil
Addrss - 4 nil
Addrss - 5 nil
Addrss - 6 nil
Addrss - 7 nil
Addrss - 8 nil
Addrss - 9 nil
Addrss - 10 nil
Addrss - 11 nil
Addrss - 12 nil
Addrss - 13 nil
Addrss - 14 nil
Addrss - 15 nil
Addrss - 16 nil
Addrss - 17 nil
Addrss - 18 nil
Addrss - 19 nil
Addrss - 20 nil
Addrss - 21 nil
Addrss - 22 nil
Addrss - 23 nil
Addrss - 24 nil
Addrss - 25 nil
Addrss - 26 nil
Addrss - 27 nil
Addrss - 28 nil
Addrss - 29 nil
Addrss - 30 nil
Addrss - 31 nil
Addrss - 32 nil
Addrss - 33 nil
Addrss - 34 nil
Addrss - 35 nil
Addrss - 36 nil
Addrss - 37 nil
Addrss - 38 nil
Addrss - 39 nil
Addrss - 40 nil
Addrss - 41 nil
Addrss - 42 nil
Addrss - 43 nil
Addrss - 44 nil
Addrss - 45 nil
Addrss - 46 nil
Addrss - 47 nil
Addrss - 48 nil
Addrss - 49 nil
Addrss - 50 nil
Addrss - 51 nil
Addrss - 52 nil
Addrss - 53 nil
Addrss - 54 nil
Addrss - 55 nil
Addrss - 56 nil
Addrss - 57 nil
Addrss - 58 nil
Addrss - 59 nil
Addrss - 60 nil
Addrss - 61 nil
Addrss - 62 nil
Addrss - 63 nil
Addrss - 64 nil
Addrss - 65 nil
Addrss - 66 nil
Addrss - 67 nil
Addrss - 68 nil
Addrss - 69 nil
Addrss - 70 nil
Addrss - 71 nil
Addrss - 72 nil
Addrss - 73 nil
Addrss - 74 nil
Addrss - 75 nil
Addrss - 76 nil
Addrss - 77 nil
Addrss - 78 nil
Addrss - 79 nil
Addrss - 80 nil
Addrss - 81 nil
Addrss - 82 nil
Addrss - 83 nil
Addrss - 84 nil
Addrss - 85 nil
Addrss - 86 nil
Addrss - 87 Detected device address is  0x57 (87)
Addrss - 88 nil
Addrss - 89 nil
Addrss - 90 nil
Addrss - 91 nil
Addrss - 92 nil
Addrss - 93 nil
Addrss - 94 nil
Addrss - 95 nil
Addrss - 96 nil
Addrss - 97 nil
Addrss - 98 nil
Addrss - 99 nil
Addrss - 100 nil
Addrss - 101 nil
Addrss - 102 nil
Addrss - 103 nil
Addrss - 104 Detected device address is  0x68 (104)
Addrss - 105 nil
Addrss - 106 nil
Addrss - 107 nil
Addrss - 108 nil
Addrss - 109 nil
Addrss - 110 nil
Addrss - 111 nil
Addrss - 112 nil
Addrss - 113 nil
Addrss - 114 nil
Addrss - 115 nil
Addrss - 116 nil
Addrss - 117 nil
Addrss - 118 nil
Addrss - 119 nil
Addrss - 120 nil
Addrss - 121 nil
Addrss - 122 nil
Addrss - 123 nil
Addrss - 124 nil
Addrss - 125 nil
Addrss - 126 nil
Addrss - 127 nil
Scanning End
>

ESP32 NodeMCU I2C Interface: Code Explanation

This table format provides a structured breakdown of each section of the code along with its explanation.

Section	Explanation
Setup Section
id	Defines the I2C interface as software-based.
pinSDA	Specifies the GPIO pin used for the data line (SDA) of the I2C interface.
pinSCL	Specifies the GPIO pin used for the clock line (SCL) of the I2C interface.
speed	Sets the speed of the I2C communication to slow. Only `i2c.SLOW` speed is supported.
Initialization
i2c.setup()	Initializes the I2C module with the specified parameters: interface ID, SDA pin, SCL pin, and speed.
Scanning for Devices
print(“Scanning Started….”)	Prints a message indicating the start of device scanning.
Looping through device addresses	Iterates through device addresses from 0 to 127.
i2c.start()	Sends an I2C start condition.
i2c.address()	Sets up the I2C address and read/write mode for the next transfer.
i2c.stop()	Sends an I2C stop condition.
Check Status	Checks the status of the address detection: If `Status` is true, prints the detected device address in hexadecimal and decimal format. If `Status` is false, prints “nil” for the address.
print(“Scanning End”)	Prints a message indicating the end of device scanning.

Suggest

ESP8266 NodeMCU Module – I2C : https://aruneworld.com/embedded/esp8266/esp8266-nodemcu/esp8266-nodemcu-module-i2c/

NodeMCU Get Start

NodeMCU Build Firmware

NodeMCU Flash Firmware

NodeMCU IDE

ESP8266 NodeMCU Modules

NodeMCU Module–Firmware Info

NodeMCU Module – GPIO

NodeMCU Module – Node

NodeMCU Module – WiFi

NodeMCU Module – Timer

NodeMCU Module – I2C

NodeMCU Module – File

NodeMCU Module – NET

NodeMCU Module – HTTP

NodeMCU Module – MQTT

ESP8266 NodeMCU Interface

NodeMCU Interface LED

NodeMCU Interface Button

NodeMCU Interface 7 Seg

NodeMCU Interface LCD

NodeMCU Interface ADC

NodeMCU Interface DHT11

NodeMCU Interface MCP23008

NodeMCU Interface MCP23017

NodeMCU Interface ADXL345

NodeMCU Interface DS18B20

ESP8266 NodeMCU Tutorials

NodeMCU Tutorials Google Time

NodeMCU Tutorials WebServer

ESP8266 NodeMCU Projects

Imperial March Ringtone Play

WiFi Router Status Indicator

ESP8266 NodeMCU Project – Home Automation

Others

NodeMCU All Post

Sitemap

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ESP32 NodeMCU Interface – DS1B20

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ESP32 NodeMCU Module – Basic UART, Timer

ESP8266 and ESP32 NodeMCU Lua Module functions are different. So we can’t use ESP8266 fuctions directly in ESP32 Check the Official Documentation of NodeMCU Lua for ESP32

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ESP32 NodeMCU – Basic Interface Examples

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Embedded Sensor – DHT11

Aosong DHT11 is a low cost humidity and temperature sensor with a single wire digital interface. The sensor includes a resistive sense of wet components and an NTC temperature measurement devices, and connected with a high–performance 8–bit microcontroller. DHT11 uses a simplified single-bus communication. The sensor is calibrated and doesn’t require extra components so you can get right to measuring relative humidity and temperature.

DHT11 output calibrated digital signal. It utilizes exclusive digital-signal-collecting-technique and humidity sensing technology, assuring its reliability and stability. Its sensing elements are connected with 8-bit single-chip computer. Every sensor of this model is calibrated in accurate calibration chamber and the calibration-coefficient is saved in type of programmer in OTP memory, when the sensor is detecting, it will cite coefficient from memory. for more details about data sheet of DHT11 sensor click here.

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ESP32 Lua-RTOS – IDE Setup and Firmware Flash

Lua RTOS is an open-source real-time operating system (RTOS) designed to run Lua applications on microcontrollers and other embedded systems. It aims to provide a lightweight and efficient platform for developing embedded applications with Lua scripting capabilities.Here will discuss ESP32 Lua RTOS Flash Firmware tutorial.

Overall, Lua RTOS is a versatile and lightweight operating system that empowers developers to build embedded applications with Lua scripting capabilities. Its integration with popular microcontroller platforms and active community support make it a compelling choice for IoT and embedded systems development. We tested with EPSressif ESP-Wroom-32 Dev Board and ESP32 Core firmware with the ESPressif Flash tool.

Feature	Description
Language	Lua RTOS is built on Lua, a lightweight scripting language. Lua is known for its simplicity, ease of use, and flexibility, making it ideal for embedded systems development.
Real-Time Operating System	Lua RTOS provides a real-time operating system (RTOS) environment for embedded systems. It offers task scheduling, inter-task communication, and synchronization mechanisms.
Supported Hardware	Lua RTOS supports various microcontroller architectures, including ESP32, ESP8266, STM32, and others. It is highly portable and can be adapted to different hardware platforms.
Multitasking	Lua RTOS enables multitasking, allowing multiple Lua scripts to run concurrently as separate tasks. Tasks can communicate and synchronize through message passing and semaphores.
File System	Lua RTOS includes a file system API for accessing files on external storage devices such as SD cards or SPI flash memory. It supports file operations like reading, writing, and listing.
Networking	Lua RTOS supports networking protocols such as TCP/IP, UDP, MQTT, and HTTP. It allows embedded devices to communicate over Ethernet, Wi-Fi, or other network interfaces.
Peripheral Support	Lua RTOS provides APIs for interfacing with various peripherals such as GPIO, UART, SPI, I2C, ADC, DAC, and more. Developers can easily control and communicate with hardware components.
Development Environment	Lua RTOS development can be done using lightweight text editors or integrated development environments (IDEs) with Lua support. It offers flexibility in choosing development tools.
Community	Lua RTOS has an active community of developers and users who contribute to its development, share knowledge, and provide support through forums, mailing lists, and social media.

This table summarizes the key features and characteristics of Lua RTOS, providing an overview of its capabilities and suitability for embedded systems development.

Setting up Lua RTOS

Step	Description
1. Obtain Lua RTOS	Download Lua RTOS from the official repository or source.
2. Install prerequisites	Install any required dependencies, such as Git and GCC, according to Lua RTOS documentation.
3. Set up development environment	Configure your development environment, including setting up a terminal and text editor.
4. Initialize project directory	Create a new directory for your Lua RTOS project.
5. Write your Lua code	Develop Lua scripts and application logic within the project directory.
6. Configure Lua RTOS	Customize Lua RTOS configuration files to match your project requirements.
7. Compile Lua RTOS	Use the provided build system to compile Lua RTOS for your target hardware platform.
8. Flash Lua RTOS	Flash the compiled Lua RTOS image to your target hardware using tools like esptool.py.
9. Test your application	Verify the functionality of your Lua RTOS application on the target hardware platform.
10. Iterate and improve	Continuously refine your Lua RTOS application based on testing feedback and requirements.

Firmware

Where to get Lua-RTOS firmware? (Pr-compiled binaries)

Flash Tool

The software and hardware resources required for downloading firmware to flash are
listed below.

Hardware:
o 1 x module to which firmware is downloaded
o 1 x PC (Windows 7 [64 bits], Windows 10)
Software:
Download Tool: Flash Download Tool ESpressif Flash Download Tool,

This tool supports the following SOCs

ESP32 series
ESP8266 series
ESP32-S2 series
ESP32-C3 series
ESP32-S3 series
ESP32-C2 series
ESP32-C6 series
ESP32-H2 series

Steps to follow

Download the appropriate firmware for your ESP32 board from the provided link. Once you’ve downloaded the appropriate firmware, unzip the file anywhere on your machine. Similarly, download the Flash tool from the same link and unzip it. Next, open the flash tool designed for ESP32 and configure the following parameters:

Baud rate: 921600
Flash mode: “dio”
Flash frequency: “40m”

For flashing the firmware, use the following addresses:

Bootloader.WHITECAT-ESP32-N1.bin – Address: 0x1000
lua_rtos.WHITECAT-ESP32-N1.bin – Address: 0x10000
partitions_singleapp.WHITECAT-ESP32-N1.bin – Address: 0x8000

For flashing the file system, use:

spiff_image.WHITECAT-ESP32-N1.Bin

Once the flashing process is complete, you’re all set.

Note: Make sure to adjust the “esp-idf path” and “usb path” as per your requirements.

Connect to the Console

Connect any UART Serial Tool to your device and configure the following parameters:

Speed: 115200 bauds
Data bits: 8
Stop bits: 1
Parity: None
Terminal emulation: VT100

Ensure these settings are accurately configured for seamless communication between your devices.

after connecting esp32 to the PC you will see the following.

   /\       /\
  /  \_____/  \
/_____________\
W H I T E C A T

Lua RTOS beta 0.1 build 1479953238 Copyright (C) 2015 - 2017 whitecatboard.org
cpu ESP32 at 240 Mhz
spiffs0 start address at 0x180000, size 512 Kb
spiffs0 mounted
spi2 at pins sdi=012/sdo=013/sck=014/cs=015
sd0 is at spi2, pin cs=015
sd0 type II, size 1943552 kbytes, speed 15 Mhz
sd0a partition type 0b, sector 227, size 1943438 kbytes
fat init file system
fat0 mounted
redirecting console messages to file system ...

Lua RTOS beta 0.1 powered by Lua 5.3.4


Executing /system.lua ...
Executing /autorun.lua ...

/ >

ESP32 Lua RTOS Flash Firmware tutorial

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ESP32 Lua-RTOS Modules- Basic Examples

In this “ESP32 Lua-RTOS Modules- Basic Examples” article we will explore the PIO Module (GPIO) and Interface LED as well as Buzzer, Wifi, MQTT, EEPROM I2C Code.

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Embedded Interface – PCF8574 and PCF8574A I/O Expender

In this article we are discussing Embedded Interface – PCF8574 and PCF8574A I/O Expender.

The PCF8574 device provides general-purpose remote I/O expansion for most micro controllers
families by way of the I2C interface [serial clock(SCL), serial data (SDA)]. 8-bit 2.5- to 5.5-V I2C/SMBus I/O expander with interrupt

The device features an 8-bit quasi-bidirectional I/O port (P0–P7), including latched outputs with high current drive capability for directly driving LEDs. Each quasi-bidirectional I/O can be used as an input or output without the use of a data-direction control signal. At power on, the I/Os are high. In this mode,
only a current source to VCC is active.

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PIC MCU – UART Communication

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Embedded Interface – LCD HD44780

HD44780 compliant controllers 16×2 Character LCD is a very basic and low-cost LCD module that is commonly used in electronic products and projects.
16×2 means it contains 2 rows that can display 16 characters.
Its other variants such as 16×1 and 16×4 are also available in the market.
In these displays, each character is displayed using 5×8 or 5×10 dot matrix.

Experiments

Change Cursor Location Based on Key Input

LCD4 Bit Mode Functions

void Lcd4_Clear()   {    Lcd4_Cmd(0x00);    Lcd4_Cmd(0x01);    }    // clear screen 0x01

void Lcd4_DisplayOFF_BlinkON_CursorON()        {    Lcd4_Cmd(0x00);    Lcd4_Cmd(0x0B);    }    // 0x0B

void Lcd4_DisplayON_BlinkOFF_CursorOFF()    {    Lcd4_Cmd(0x00);    Lcd4_Cmd(0x0C);    }    // 0x0C

void Lcd4_DisplayON_BlinkOFF_CursorON()     {    Lcd4_Cmd(0x00);    Lcd4_Cmd(0x0D);    }    // 0x0C

void Lcd4_DisplayON_BlinkON_CursorOFF() {    Lcd4_Cmd(0x00);    Lcd4_Cmd(0x0E);    }    // 0x0E

//void Lcd4_Shift_Left()                      {   Lcd4_Cmd(0x01); Lcd4_Cmd(0x08); }   //  0x18

//void Lcd4_Shift_Right()                     {   Lcd4_Cmd(0x01); Lcd4_Cmd(0x0C); }   //  0x1C

Next Topic

Embedded Interface 7 Segment (Add Soon)

Embedded Interface ADC (Add Soon)

Embedded Interface Button (Add Soon)

Embedded Interface EEPROM (Add Soon)

Embedded Interface LCD (Add Soon)

Embedded Interface LCD HD44780 (Add Soon)

Embedded Interface LED

Embedded Interface MCP23017

Embedded Interface Motor (Add Soon)

Embedded Interface PCF8574 and PCF8574A

Embedded Interface RTC (Add Soon)

Embedded Interface Switch

Embedded Interface Touch Kypad

Embedded Interface RGB LED (Add Soon)

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ESP32 – Resource

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Embedded Protocol – UART

UART (Universal Asynchronous Receiver/Transmitter) is a standard communication protocol used for serial communication between devices. It’s commonly employed in embedded systems for communication between microcontrollers, sensors, and other peripheral devices.

In the context of embedded systems, UART is often used as a hardware communication protocol, enabling devices to transmit and receive data serially. The UART communication involves two pins: TX (transmit) and RX (receive).

It’s is full-duplex communication
UART contains a shift register
which is the fundamental method of conversion between serial and parallel forms.

Type of Communication: Asynchronous (No clock).
Rule: The transmitter and receiver should same baud rate. Data format and transmission speed are configurable.
UART Uses serial communication over a computer or peripheral device serial port. (Electronics Devices).

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Embedded Protocol – SPI Communication

SPI is an abbreviation for Serial Peripheral Interface, which stands for Synchronous Serial Communication Interface. It is utilized for short-distance communication and was developed by Motorola in 1980, later becoming a de facto standard. SPI communication operates in full-duplex mode. It is also sometimes referred to as the Four-Wire Serial Bus (FWSB), distinguishing it from Three, Two, and One Wire Serial Bus protocols. The four-wire protocol includes SCL, SS, MISO, and MOSI. SPI operates as a single master protocol.

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Embedded Protocol – MQTT

Message Queue Telemetry Transport (ISO/IEC PRF 20922), or MQTT, is a lightweight protocol designed for machine-to-machine (M2M) device communication using a Publish/Subscribe pattern. It was developed by Message Queue Telemetry Transport (ISO/IEC PRF 20922) and Lightweight protocol for (M2M) device communication using Publish/Subscribe. It was Developed By Andy Stanford-Clark (IBM) and Arlen Nipper (Eurotech; now Cirrus Link) in 1999. Unlike HTTP, which follows a request/response paradigm, It utilizes a publish/subscribe architecture. The central communication point in It is the Broker. It is available for implementation in C, C++, JavaScript, Lua, Python, and soon in C#.

Client functions

Field	Description
Host	Address of the MQTT broker.
Port	Default: 1883.
ClientID	Unique client identifier.
Username	UTF-8 encoded string for authentication.
Password	Client’s password if flag set.
Keep Alive	Duration client stays connected (seconds).
SSL	Indicates SSL/TLS encryption usage.
Clean Session	If set, session clears subscriptions and messages.
Last-will Topic	Topic for “Last Will” message on disconnect.
Last-will QoS	Quality of Service for “Last Will”.
Last-will Retain	Retain status for “Last Will” message.
Last-will Message	Content of “Last Will” in case of disconnection.
Topic	Message destination hierarchy.
+ Plush sign	Single-level wildcard in subscriptions.
# Hash Sign	Multilevel wildcard in subscriptions.
Publish QoS	Quality of Service levels:
	QoS(0) – At most once
	QoS(1) – At least once
	QoS(2) – Exactly once
Retain	Message retention by broker.
Subscriptions	List of subscribed topics.
Message	Payload data transmitted.
Broker	Server distributing messages.
Client	Device or app connected to broker.
Quality of Service	Message delivery guarantee.
Retained Messages	Broker-stored messages for new subscribers.
Persistent Session	Broker-maintained session after client disconnects.
Last will and Testament and SYS topic	Client’s “Last Will” message and system topics interaction.

PHP MQTT

CloudMQTT

Web Apps

Chrome App: webstore
Firefox extension: addons

WordPress Plugin

DIOT SCADA with MQTT By Ecava

Image Source

DIOT which stands for Decoupled IOT, has its SCADA functionalities decoupled into Host and Node for flexibility and scalability that catered for IoT era. This plugin functions as the SCADA Host to work with your device or system, which will be treated as SCADA Node. You just need to enter the broker/server into the configuration. You may then subscribe to the desired topic with a shortcode to display in any desired web page or post. [diot topic="building/floor/device/sensor"] Or, if you have a JSON content, you may add dollar sign as JSON root: [diot topic="building/floor/device/sensor$json.data"]. The content will be updated dynamically when the device publish any data. You may also choose to display your realtime data in trending chart. Check out Ecava DIOT online demo to see how easy things can be done now! For more see here : https://wordpress.org/plugins/ecava-diot-scada/

Image Source

WP-MQTT By Roy Tanck

Setting up Tthis is easy. Simply supply your MQTT broker’s details and configure which WordPress events should trigger messages. “MQTT is a machine-to-machine (M2M)/”Internet of Things” connectivity protocol. It was designed as an extremely lightweight publish/subscribe messaging transport.” (from mqtt.org) A number of events are predefined. Simply check the right checkbox and fill in the message’s subject and text.

Pageview
User login
Failed user login
Post published
Page published
New comment

Other events can be added using the “custom events” section. This allows you to use any WordPress hook (actions and filters) to trigger messages.

Image Source

Android App

Check this below name in Play-store

Dashboard
IOT Manager
IOT

Broker Service Supporter

The following list of brokers may be used online or locally also giving free and paid service

Adafruit IO (Online – Free)

Website : Adafruit IO
Adafruit supporting online free service.
You can use adafruit client libraries to Python, Node JS, Rubby and Arduino. see the client libraries section).
The following details are to connect a client to Adafruit IO.
- Host : io.adafruit.com
- Port : 1883 or 8883
- Username : Your adafruit account username
- Password : Your adafruit IO Key

CloudMQTT (Online -Free and Paid)

Website :
CloudMQTT
Online – Free Plans : Cute Cat and
Paid Plans : Keen Kola, Loud Leopard, Power Pug)
Using Amazon Web Service
Type : mosquitto

HiveMQ (Online -Free and Paid)

Connect to Public Broker

Dashboard
- Broker: broker.hivemq.com
- TCP Port: 1883
- Websocket Port: 8000
Web socket Client : http://www.hivemq.com/demos/websocket-client/
- Broker: broker.mqttdashboard.com
- TCP Port: 1883
- Websocket Port: 8000

Setup local instance

Genral Download HiveMQ
Arun Requested : Downloaded Link
- Installation as Windows Service

m2m

Free public broker service

q.m2m.io
- Broker: q.m2m.io
- Port: 1883.
- Application : Facebook messenger

Mosquitto (Local and Online free)

Eclipse Mosquitto™ is an open source v3.1/v3.1.1 Broker.

Free public Service

iot.eclipse.org
- Broker: iot.eclipse.org
- Port: 1883, 80(WebScoket), 443 (WebSockets+SSl)
mosquitto
- Broker : test.mosquitto.org
- Port:
  - 1883 : MQTT, unencrypted
  - 8883 : MQTT, encrypted
  - 8884 : MQTT, encrypted, client certificate required
  - 8080 : MQTT over WebSockets, unencrypted
  - 8081 : MQTT over WebSockets, encrypted
  - 80(WebScoket), 443 (WebSockets+SSl)

rabbitMQ

https://www.rabbitmq.com/
Install on windows
- Download rabbit for windows :
- Installation guide

Free public broker service

dev.rabbitmq.com
- Broker: dev.rabbitmq.com
- Port: 1883,

SimpleML

Free MQTT service to evaluate Machine Learning models, documentation

Free public broker service

simpleml
- Broker: mqtt.simpleml.com
- Port : 1883 (MQTT), 8883 (MQTT +SSl), 80(REST), 80(WebSockets), 5683 (CoAP)

Other free public broker service

dioty.co
- Broker : dioty
- Port : 1883 (MQTT), 8883 (MQTT +SSl), 80(REST), 8080(WebSockets), 8880 (WebSocket +SSL)
swifitch.cz
- Broker :mqtt.swifitch.cz
- Port : 1883 (MQTT)

Interview Questions

https://aruneworld.com /embedded/interview-questions-mqtt/

Reference

Hits (since 2024-Jan-26) - 1,319

Embedded Protocol – COAP

COAP, or Constrained Application Protocol, a specialized web transfer protocol, is designed for constrained devices and low-power, low-bandwidth networks commonly found in Internet of Things (IoT) and Machine-to-Machine (M2M) applications. CoAP is an application layer protocol similar to HTTP but optimized for constrained environments.

This, designed to be simple and lightweight, is ideal for resource-constrained devices, operating over UDP instead of TCP to reduce complexity. It supports request/response interactions like HTTP and offers features such as multicast support and resource discovery. CoAP facilitates efficient communication between constrained devices and web servers, fostering the development of scalable IoT solutions.

Getting Started with Terminal by Br@y tool

Terminal is a simple serial port(COM) terminal emulation program
Used for communication with different devices (Modem, routers, embedded uC systems, GSM Phones. GPS Modules)
Very useful debugging tool for serial communication applications

Read more… →

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What is Cayenne MyDevice?

Where Buy this Sensor

Data Sheet

Suggest to study

Uses

Pr-Request to Lean

ESP32 NodeMCU Module I2C Functions

Code of ESP32 I2C Scanner

Results

ESP32 NodeMCU I2C Interface: Code Explanation

Suggest

NEXT

Overview of Lua RTOS

Setting up Lua RTOS

Firmware

Flash Tool

Steps to follow

Connect to the Console

Experiments

LCD4 Bit Mode Functions

Next Topic

Client functions

PHP MQTT

Web Apps

WordPress Plugin

DIOT SCADA with MQTT By Ecava

WP-MQTT By Roy Tanck

Android App

Broker Service Supporter

Adafruit IO (Online – Free)

CloudMQTT (Online -Free and Paid)

HiveMQ (Online -Free and Paid)

Connect to Public Broker

Setup local instance

m2m

Mosquitto (Local and Online free)

rabbitMQ

SimpleML

Other free public broker service

Interview Questions

Reference

Getting Started with Terminal by Br@y tool