Articles

Wifi controlled smart light bulbs can now be purchased from less than USD 10. However, those can often only be used by a specific application provided by the vendor and can involve exchanging data with a third party server. I wanted a solution to use my own software while benefiting from the cheap hardware so I replaced the wifi module of a a cheap Wifi light bulb my own electronics.

As a graph database Neo4J is a great choice to manage highly relational data. On the other side, a great number of applications feature at least some form of user management system. With Neo4J, those users can be store as nodes and connected to other items via relationships. A typical example would be a blog, where both articles and users are individual nodes while authorships are represented by a relationship.

More often than not, web applications require restrictions regarding who can access the content that they serve. This involves an user management and authentication system, which, if designed inappropriately, can lead to security concerns. However, the development of such system can be time consuming, especially if done repeatedly for multiple applications.

Although probably in the decline, infrared is a common way to remotely control household appliances such as air conditioners or TVs. Being able to turn on an AC unit without leaving the sofa is definitely comfortable, but sometimes it would be even better to be able to do it before even getting home. In order to control those various appliances, I designed a simple WiFi controlled IR emitter.

Over the years, I have built multiple IoT devices ranging from AC controllers to ceiling lights. Usually, I would control those devices using my smartphone or computer but sometimes a physical button can be more convenient. Thus, I designed this simple IoT button which publishes MQTT messages when pressed.

Modules like the Wemos D1 mini are a relatively cheap and easy way to integrate an ESP8266 in a project. However, one would sometimes require to have more freedom over the electronics, especially when it comes to PCB layout. For this purpose, the ESP8266 can be used in a form factor closer to its raw form, the ESP12-F module.

Compared to other countries, Japan did not enforce a strict lockdown on its population during the COVID-19 pandemic. As a result, most bars and restaurants continued their operations as usual. However, in order to prevent the spread of the virus as much as possible, the staff of my local pub printed out signs asking customers to not leave their table without wearing a mask.

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.

IP cameras are cheaper than ever and with the ESP32-CAM boards it is now possible to stream video for less than USD 10. However, IP cameras are commonly either only accessible from within their network, or use servers from third party companies to allow users to see the video feed from anywhere in the world. As both scenarios are inconvenient, I decided to create a camera viewer application that can proxy the video feed to a web interface.

I am not much of a cook so salads are usually one of my favorite options for a healthy meal. So, just like for everything else, I started wondering if I could make my own. However, I don't have access to a garden so I started looking into solutions to grow vegetables indoors. I settled for hydroponics, which seemed to provide a good balance between yield and operational hassle. Specifically, I went for a Deep Water Culture type of hydroponic system as it is usually considered easy for beginners to setup.