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Send DHT11 temperature/humidity data using MQTT

The following tutorial show you how you can send temperature and humidity data measured by DHT11 sensor connected to a nodeMCU / ESP8266 board with MQTT message. The messages are displayed in the WEB MQTT interactive MQTT web client dashboard with the gauge and chart UI elements. https://rundebugrepeat.com/webmqtt/ The following DHT11 library used: https://github.com/adafruit/DHT-sensor-library Source …

WEB MQTT – NodeMCU / ESP8266

The following video will shows how to control nodeMCU / ESP8266 with MQTT messages. In this first example I will control the builtin LED of the module with mqtt messages. The messages ar sent from the dashboard with buttons and a switch with pre-defined “on” and “off” messages. https://rundebugrepeat.com/webmqtt/ source code for the arduino code:

Install Mosquitto MQTT Broker on Raspberry Pi

In this post I will show you how to install Mosquitto MQTT broker on Raspberry Pi or Orange Pi embeded systems. Prerequisites Raspberry Pi, or Orange Pi board with debian-based operating system installed on it. Power supply and internet connection to the board Installation1.: Open a new terminal window 2.: Update the system with:pi@raspberry:~ $ …

Free MQTT Brokers

To run an MQTT based application you need to host an MQTT Broker (a server). In this post I will show you several free to use, open-source brokers. Eclipse Mosquitto Mosquitto by eclipse.org is a lightweight MQTT broker implementation with support MQTT versions 3.1.0, 3.1.1 and version 5.0.The software is free to dowload from: https://mosquitto.org/download/ …

NodeMCU

IntroductionNodeMCU is an ESP8266 Wi-Fi SoC (System On a Chip) based, open soruce IOT platform. The Base chip is an ESP8266 ESP-12 module.The name, “NodeMCU” refers mainly to the firmware itself, rather than the develeopment kit. The firmware uses Lua scripting language, but also available for Arduino IDE platform. So if you are familiar with …

MQTT – LWAT, Last Will and Testament

MQTT protocol often used in network, where bandwith or signal is limited between the clients and the broker. These limitations can cause unexpected disconnections of clients from the network and the broker. It can cause trouble if we rely on the messages in our application and can not tell if the client is disconnected. There …

MQTT – Introduction

MQTT, or Message Queuing Telemetry Transport is an open source, standard, publish-subscribe base network protocol. The use of the protocol is to transport messages over the network between devices. It is an OASIS and ISO Standard (ISO/IEC PRF 20922). It is designed to be a lightweight, small code footprint and limited network bandwith communication protocol.

MQTT QoS, Quality of Service

In MQTT protocol, with QoS (Quality of Service) we define an agreement between the client and the broker about the message delivery level. This level is defined at two point. When the client is Subscribed to a topic (path) and when the client is publish a message.There are 3 levels of QoS: level 0: The …