• Abhijit Ghosh Abhijit Ghosh Posted 55 Articles A java/j2ee developer. Love to share learning experiences on different technologies/frameworks.
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Internet enabled (IOT) smoke alarm with SMS notification using esp8266, MQ2, ThingSpeak and Twilio

By Abhijit Ghosh on Sep 4, 2017 1:50:56 PM

"Ladybird, ladybird, fly away home, / Your house is on fire, / Your children shall burn!" Our smart homes are crowded with smart gadgets and appliances. Was just wondering, is it safe enough? Let's do something to make our home both smart and safe. We'll build an internet enabled (IOT) smoke and fire alarm to send SMS notification and to trigger alarm with flashing red LED if it detects smoke and leakage of combustible gas.


IOT - Home Automation project using Geofencing, MQTT, ESP8266 and MycroPython

By Abhijit Ghosh on May 8, 2017 10:01:28 AM

After a long day at office, wouldn't it be great to step into a cool room without having to wait for the air conditioning to start functioning? I am sure all of us has unlocked the just locked door to double check if the electrical appliances have indeed been switched off. For ones who own a personal garage, it would feel great to watch the garage door open as you drive in without having to step out of your car. So lets explore a home automation use case that would map the switching on/off of appliances with the entry/exit of a preset geofence (virtual perimeter for a real-world geographic area).


Home Automation - Internet of Things - MQTT (MQ Telemetry Transport), ESP8266 and MycroPython

By Abhijit Ghosh on Mar 22, 2017 3:51:40 AM

This is my first post on home automation. As a 'Hello World' project, switching on/off a bulb is a common use case. This post is not an exception. But to spice it up, we'll use MQTT (MQ Telemetry Transport) - a machine-to-machine (M2M)/Internet of Things (IOT) connectivity protocol and an android app (IoT MQTT Dashboard). Bulb is merely a symbolic representation of an electrical device. We can practically control any device (Internet of Things) over internet.


Configure STA_IF interface of ESP8266 (MycroPython firmware) to connect with WIFI network automatically on boot

By Abhijit Ghosh on Mar 14, 2017 3:06:19 AM

ESP8266 can act as both Station / WIFI client (STA_IF interface) and Access Point (AP_IF interface). AP_IF interface is active by default in MycroPython firmware on ESP826 . In the earlier post, we connected to the access point (AP mode) of ESP8266 and used WebREPL to remotely control switch on/off and brightness of an LED. Now, we'll configure the ESP8266 (as WIFI client) so that it connects to the WIFI router automatically after booting.


Example: Remotely switch on/off and control brightness of an LED using MicroPython WebREPL

By Abhijit Ghosh on Mar 8, 2017 1:49:40 AM

So far, we have flashed MicroPython firmware onto an ESP8266 and setup WebREPL to run programs over WIFI on the chip. Now it's time for a hands-on excercise. We'll remotely switch on/off and control brightness of an LED using MicroPython WebREPL.


How to setup WebREPL to connect to Python prompt (REPL) of ESP8266 over WIFI network?

By Abhijit Ghosh on Feb 23, 2017 2:05:33 AM

WebREPL daemon auto-start is disabled by default in MycroPython on ESP8266 for security reason. Here, we'll enable the same, connect to the REPL over WIFI using locally installed WebREPL client and run a "Hello World" program remotely on the chip.


How to flash MicroPython firmware onto an ESP8266 ESP-12E chip using esptool?

By Abhijit Ghosh on Feb 4, 2017 12:01:35 PM

By default, ESP8226 module comes with AT Firmware. In this post, we'll see how to flash MicroPython firmware onto an ESP8266 ESP-12E chip using esptool.


How to uninstall OpenCV (Open Source Computer Vision) from Raspberry Pi - Raspbian Jessie?

By Abhijit Ghosh on Jul 10, 2016 4:05:12 PM

To uninstall OpenCV (Open Source Computer Vision) from Raspberry Pi (Raspbian Jessie), follow the steps mentioned below in this article.


Install and Configure Oracle Java ME Embedded on Raspberry Pi

By Abhijit Ghosh on Mar 17, 2015 10:14:14 PM

Raspberry Pi is a low cost, credit-card sized and fastest selling personal computer. In this article, we'll install and configure Oracle Java ME Embedded on a Raspberry Pi.


Build, Install and Configure Eclipse Plugin for Apache Hadoop 2.2.0

By Abhijit Ghosh on Apr 23, 2014 2:10:18 PM

Apache Hadoop Development Tools (HDT) is still in development phase. So, no official distribution of Hadoop 2.2.0 Eclipse Plugin is available now. But we can build the same using winghc/hadoop2x-eclipse-plugin. In this post, we'll build, install and configure the plugin with the Eclipse or any Eclipse based IDE (say, Spring Tool Suite) to ease the development activities using Hadoop framework.


About this 'Hello World' site

This site is mainly developed to share coding and technology learning experiences on java / j2ee based technologies.

Simple tutorials / codes have been shared to learn a new technology. Full source code is also available for download.