Articles

I got my hands on a 600W 12V inverter so I decided to experiment with generating my own electricity.

I've been using&nbsp;<a href="https://www.home-assistant.io/" rel="noopener noreferrer nofollow">Home Assistant</a>&nbsp;to control my home IoT devices for a while. Although it fulfills all my needs, I wanted to make my own system so as to get a fully customized smart home control panel and learn how to build such an application in the process.

The SONOFF S20 is a cheap Wifi smart socket that enables the remote control of appliances for less than USD 10. Although the hardware is more than decent, its usage requires a proprietary app which most likely involves a third party server between the user and the device. Since the socket uses an ESP8266 at its core, I decided to write my own firmware for it.

Mosquitto is usually the first candidate to come to mind when looking for an MQTT broker. However, by default, Mosquitto manages users using a password file. This makes it difficult to easily add or remove users, especially when the broker is deployed in Kubernetes.

A simple framework using Three.js and MQTT to easily create digital twins

With the cloud native multi-user MQTT platform deployed, I started designing IoT devices that I could distribute to end users. However, without a GUI, interacting with those devices would be difficult. Of course, one could install applications like MQTT dash or similar but this would require tedious configuration such as MQTT broker and topics. I wanted to give users a simpler UX so I made this simple control interface that automatically displays a users devices and allows those to be controlled.

A Node.js application which stores data from IoT devices sent over MQTT into an InfluxDB time-series database. It allows the management of multiple data sources into a MongoDB database.

This is an IoT ceiling light controller which includes an HC-SR501 PIR motion sensor. It is built around a Wemos D1 mini (ESP8266 breakout board), which controls a homemade TRIAC breakout board. TRIACs provide the advantage of switching devices on and off silently, as opposed to a mechanical relay.

Although a wide variety of sensing devices can be envisioned for home automation systems, motion and temperature sensors are among the most widespread. This is mostly due to their low cost and simplicity of use. In order to equip multiple rooms of my apartment with such sensors, I designed a simple IoT sensing module that can easily be produced in any quantity.