kao's Blog

Hi I'm Kalle, a software developer from Kiel working for Cap3. Besides my day-job I like to spread my knowledge and so I started to work with opencampus.sh to offer free courses on web-development.

You can find and contact me on the following platforms:

Building an automated greenhouse Pt. III

14-01-2019
This is the last session and finishes the greenhouse project. The most parts are already done, but one important part is still missing. The…

Building an automated greenhouse Pt. II

07-01-2019
In the last session we connected a soil moisture sensor to the cloud and can collect its data now. But these values are not very useful…

Building an automated greenhouse Pt. I

17-12-2018
The course is coming slowly to an end, so it’s time to bring all knowledge together and start building something useful. The goal is to have…

Data visualization

10-12-2018
After collecting data the next step is to use this information. And one of the best ways to do so is paint beautiful graphs based on the…

IoT going serverless

03-12-2018
After bringing the software to the cloud last week, this session is all about the next buzzword: Serverless. Like the “cloud”, “serverless…

IoT and the cloud

26-11-2018
Whenever someone talks about the internet of things the cloud is not far. And just as the real thing the cloud in this context has no clear…

Communication protocols

19-11-2018
This session will be a bit more theoretical, because the resulting behavior of the server and the program running on the Raspberry Pi won’t…

Reading and sending sensor data

12-11-2018
One of the most common use cases of IoT is reading and collecting sensor data. Here I will show an example using the DHT11 sensor which…

Setup and first steps with the Raspberry Pi Zero

05-11-2018
The first step of using a Raspberry Pi is the preparation of the operating system, the Pi uses an SD card as primary hard drive so this step…

What is the Internet of Things?

29-10-2018
Like all heavily hyped buzzwords the question of what the IoT actually is can’t be answered in a short way. The topic ranges from embedded…

Declarative animations with react-pose

12-06-2018
In general animating the view is hard, because suddenly the state is dependent on time. Views can exist longer than they existed before…

React on the server and the JAMstack

05-06-2018
If you dig a bit deeper into the react-dom package you will find a sub folder called server and there is a function renderToString . As the…

Get firebase to sync your data

29-05-2018
Till now the chat app is quite boring, because you can only talk to yourself. But for synchronization of the message history with other…

Taking control over state-changes

22-05-2018
As already said in last session, besides handling the state itself it is very important to take care of the state changes. An extremely…

State management in a react app

15-05-2018
Handling the state of an application is one of the core features of most frameworks and even react ha a build in state API. Every class…

How to style react

08-05-2018
The classic approach to styling in the browser is creating a CSS file and provide it with a <link /> tag. The tutorial from last session…

From code to UI - Introduction to React.JS

24-04-2018
To use react we need two packages from npm, react itself and react-dom . React takes care of managing a virtual DOM representation and is…

Functional programming with JavaScript

17-04-2018
As the name “functional programming” suggests, this lesson has a heavy focus on functions. In JavaScript, you can describe a function in…

Basics and Tools

10-04-2018
The first thing you have to know before you can develop a successful web application is the platform you are running on. The “Browser…