Alex Hamelink

Privacy Policy

Fri, 23 Oct 2026 16:00:46 +0200

Overview

Welcome to my personal website.

This site is a place where I share articles, projects, experiments, and thoughts related to technology, software development, data science, and other personal interests.

I believe in collecting as little information as possible and do not use personal data for advertising, marketing, profiling, or sale to third parties.

Information Collected

This website is primarily hosted as a static site and does not intentionally collect personal information from visitors simply for reading content.

Terms of Service

Fri, 23 Oct 2026 16:00:46 +0200

Terms of Service

Acceptance of Terms

By accessing this website, you agree to use it in a lawful and respectful manner.

Comments and Content

If commenting is enabled, you are responsible for the content you submit.

Do not post unlawful, abusive, spam, malicious, or infringing content.

I reserve the right to remove comments or restrict access at my sole discretion.

No Warranty

This website and its content are provided “as is” without warranties of any kind.

Comments

Thu, 22 Oct 2026 17:36:00 +0200

This site now has comments, right below this post. I didn’t want trackers, ads or cookie banners so I’m running Remark42, a small open-source, self-hosted comment engine.

How it’s hosted

The whole thing runs as a small Docker container on Render’s free tier. Free comes with a catch though: the container’s disk is wiped every time it restarts (which happens automatically after ~15 minutes without traffic). So the comment data can’t just live there.

Renovation 2nd floor

Wed, 23 Sep 2026 15:18:18 +0200

To create an extra bedroom, we decided to thoroughly renovate the second floor. A new layout is being made and insulation is being installed under the roof.

The floor plan before and after

We start by delivering the materials. Getting everything inside is a challenge, which is why we are first bringing all the OSB boards upstairs for the floor and to finish the walls and roof. The insulation panels and wood also take up a lot of space. First we will try to use up as much of the materials before delivering more.

Pygrunn 2026

Fri, 08 May 2026 10:12:50 +0200

I visited the python conference in Groningen: PyGrunn. On this page I collect some thoughts and learnings.

FastAPI-Restly

CRUD is a problem with fastapi. There are many plugins for fastapi attempting to provide better CRUD operations. With fastapi you create a function for each operation separately. Many developers end up writing their own utils for this. Restly provides a standardized way to generate the CRUD operation endpoints for a given python class

The dark arts of ML benchmarking

“There are two possible outcomes: if the result confirms the hypothesis, then you’ve made a measurement. If the result is contrary to the hypothesis, then you’ve made a discovery”

Talentuur Microbit

Tue, 21 Apr 2026 11:51:40 +0200

This year I taught a talentuur about the BBC micro:bit. Just like last year with Python, I wanted to introduce students to programming, but this time focused on practical hardware projects. In 3 lessons, participants will learn about programming and electronics through the micro:bit.

Link to the course (in Dutch)

In lesson 1 we focused on the basics of how to program the microbit by creating a nametag and a step counter. In lesson 2 we collected data and trained a simple AI model to recognize activities similar to a fitness tracker, and in lesson 3 we measured the speed of a toy car by creating electrodes on a sloped track and measuring the time it took for the car to pass through them. When asked at the end of the course what they liked best, most students liked the second and the third lesson the best. The first lesson is important though because otherwise they will not be able to do the projects in the second and third lesson.

Lego sets

Wed, 18 Feb 2026 07:05:43 +0000

This is a list of all lego sets the kids have, for future reference. Images on this page are from brickset.com. At the bottom of this page are some instructions on how to make a list like this yourself.

Construction Excavator

set number: 60420

Custom Car Garage

set number: 60389

Desert Ranger

set number: 8408

Dog-Grooming Car

set number: 42635

Electric Sports Car

set number: 60383

F1 Driver with McLaren Race Car

set number: 60442

Fire Helicopter

set number: 60318

Fire Rescue Boat

set number: 60373

Fire Rescue Helicopter

set number: 60411

Flatbed Truck with Helicopter

set number: 31146

Fries Food Truck

set number: 60488

LEGO City Advent Calendar 2023

set number: 60381

LEGO City Advent Calendar 2025

set number: 60475

LEGO Collectables - F1 Race Cars {Random pack}

set number: 71049

LEGO Friends Advent Calendar 2023

set number: 41758

Lloyd’s Green Forest Dragon

set number: 71829

Lloyd’s Pull-Back Race Car

set number: 71828

Monster Jam DIGatron Pull-Back

set number: 42199

Monster Truck

set number: 60402

NASA Mars Rover Perseverance

set number: 30682

Off-Road Mountain Truck

set number: 60447

Police Bike Car Chase

set number: 60392

Police Car

set number: 60312

Police Off-Road Buggy Car

set number: 30664

Recycle Truck

set number: 6668

Surprising Spider

set number: 31159

The Armory

set number: 21252

Tow Truck

set number: 60435

Tow Truck Trouble

set number: 60137

Make a list like this for yourself

Create a JSON file with set numbers

This will be just a simple json file with lego set numbers.

Switching to Linux for a Mediacenter and Gaming PC.

Fri, 09 Jan 2026 16:55:00 +0100

I’ve been on the fence for a while, but the last Windows machine in our house now runs Linux. There have been annoyances for a long time, but with Windows 10 being end of life, and the upgrade tool telling me my system didn’t meet the minimum requirements for Windows 11, this was the perfect moment. This machine is mainly used for gaming by myself and the kids, and as a mediacenter to play web radio and act as a photo frame.

Foggy Night

Sat, 20 Dec 2025 22:15:54 +0100

It was a foggy night, so I went out to take some pictures of the Christmas holiday atmosphere.

50mm f/2.8 1/100sec ISO 800" >

50mm f/2.8 1/100sec ISO 400" >

50mm f/2.8 1/60sec ISO 400" >

50mm f/2.0 1/40sec ISO 400" >

50mm f/2.0 1/50sec ISO 200" >

50mm f/2.0 1/30sec ISO 100" >

50mm f/2.0 1/40sec ISO 200" >

50mm f/1.8 1/50sec ISO 100" >

50mm f/1.8 1/10sec ISO 100" >

50mm f/1.8 1/60sec ISO 400" >

50mm f/1.8 1/100sec ISO 400" >

Highlights from aiGrunn 2025

Fri, 14 Nov 2025 08:01:29 +0100

I visited the AI conference in Groningen called aiGrunn. As an AI practitioner, I was curious to see what the local AI scene in Groningen is working on. The name of the conference comes from the city of Groningen where the event is hosted, “ai” also means egg in Gronings, so there are a lot of egg references.

Talks

How AI is helping you back on the road

Yke Rusticus from ANWB is presenting how AI techniques fit in to diagnosing car trouble for roadside assistance. He showed different steps in the process of diagnosing and repairing a car where AI could help. From determining if roadside assistance was needed to planning where to send the repair vans. Quite cool to see an application of AI in a different sector than usual, even though the techniques are very similar to what I’m using in my own work.

Moon

Sun, 02 Nov 2025 09:50:14 +0100

November 5th there’s going to be a supermoon! That means the moon will be at a much closer distance. In this case 356,980 kilometers instead of the average 384,472 km. That means the moon will appear bigger and brighter in the sky. Perfect to take some cool pictures. I’m not sure if i’m going to be able to take pictures then, so I already took some practice shots tonight.

I read the best way to photograph the moon is with a low ISO to reduce noise, small aperture to improve sharpness and not too long exposure to prevent blur. I used f5.6, s1/250 ISO100

Badezimmerausstellunggeburtstagswinterfest! 🛁❄️🥳

Sun, 26 Oct 2025 20:18:53 +0100

A last-minute invitation for my 35th birthday! Just in time for you to come if you feel like it, but also late enough that you can easily get out of it with an excuse like “I have to work” if you don’t feel like it.

👗 Dresscode Oktoberfest 🍻, Apres-ski 🎿, Winter 🧣 Christmas 🎄

📅 november 15

🕗 20:00

📍 my place

Can you embroider the Night Watch in 10 years?

Wed, 22 Oct 2025 20:57:49 +0200

My wife is working on an embroidery project to recreate The Night Watch by Rembrandt. She wants to finish within 10 years. Because I like this type of thing I offered to help calculate if she was still on track.

The instruction divides the image into 96 pieces.

import os
import matplotlib.pyplot as plt
import matplotlib.dates as mdates
from nachtwacht import date_from_filename, get_finished_parts, TOTAL_PARTS
from sklearn import linear_model
import numpy as np
from datetime import datetime

get the files from the existing blogposts.

image_folder = "../content/nachtwacht/"
files = [os.path.abspath(os.path.join(image_folder, f)) for f in os.listdir(image_folder) if f.startswith("nachtwacht")]
posts = [(f, date_from_filename(f), get_finished_parts(f)) for f in sorted(files)]


dates = [d for (_,d,_) in posts]

def to_timestamp(date):
    return datetime.combine(date, datetime.min.time()).timestamp()

def dates_to_timestamps(dates):
    timestamps = [to_timestamp(d) for d in dates]
    timestamps = np.array(timestamps).reshape(-1, 1)
    return timestamps
timestamps = dates_to_timestamps(dates)
finished_parts = [fp for (_,_,fp) in posts]

Use a standard linear model

Robot Evolution

Thu, 16 Oct 2025 11:23:30 +0200

I saw a variant of the classical monkey to man evolution chart recently, applied to robotics. However I could not find a version with the actual historical revolutionary milestone robots, so I created one myself using Gemini and Nano Banana. The robots I chose to show each highlight a significant step in the evolution of robotics.

Evolution of robots from Unimate to Optimus

Unimate

The first industrial robot, Unimate, was installed in 1961 at a General Motors factory. The robot arm performed repetitive tasks such as welding and material handling, that were dangerous or monotonous for human workers. (wiki)

Bathroom and toilet renovation

Thu, 02 Oct 2025 11:42:05 +0200

After living in our house for a few years, we finally got around to renovating the bathroom. We wanted a modern bathroom and a toilet upstairs. Because the downstairs toilet also needed replacing, and it was more convenient in terms of pipes and drainage to do it at the same time, we did.

The plan

The old situation

On one side of the room was a bath, with a shower in it. On the other side a radiator. There is a door to the landing, which will remain, and a door to the drying platform which will be removed.

Using a vintage lens with a modern camera

Sun, 28 Sep 2025 16:31:31 +0200

Recently I bought the M42 Asahi Super-Takumar 55mm/1.8 lens. I read online that they would be a cheap way to get a fast lens with dreamy bokeh. I already have a Yongnuo 50mm lens that is pretty similar, but I always wanted to try out one of these vintage lenses.

how to make it work

In the case of my Nikon you cannot just connect a vintage lens to a modern camera. You have to consider the adapter ring to connect the lens to the camera body, the flange focal distance, and that you will lose a lot of features that modern lenses have, like adjusting the focus and aperture from within the camera. Using a lens with this method means you can only shoot in full manual mode. Also when doing things like this, consider that this obviously might damage your lens, and when using a DSLR the mirror may also strike the back of your lens. Proceed with caution.

Unicode Snowman

Fri, 26 Sep 2025 21:09:09 +0200

Ever since someone showed me the unicode snowman I keep thinking about the unicode snowman. It’s pretty cool how different devices and fonts render this character very differently, and how much more fun noticable it is compared to other characters.

Chess960

Fri, 26 Sep 2025 19:43:24 +0200

I’ve been playing chess with my son recently. A well known variant of chess is Chess960, also known as Fischer Random Chess. I wanted to have a generator on my own website to use to generate starting positions by number. Previously I wrote a small python script to do this, so I decided to convert it to Javascript using google gemini and embed it here.

slight difference in rules

The rules are the same as regular chess, except for the rules for castling. For details I would recommend reading the wiki article, but the short summary is that the pieces end up in the same position as they end up in regular chess.

Using an IBM Model M in the current year

Thu, 18 Sep 2025 10:36:24 +0200

A colleague of mine brought a model M to the office a few years ago. The sound and feeling of that keyboard always stuck with me, and when I was setting up my work from home setup I decided to get one for myself. The board is really nice to type on, but it takes some effort getting it to work on modern hardware. This particular board was made in 1991.

Roof

Mon, 15 Sep 2025 14:13:31 +0200

It was high time to do some painting on the underside of the overhang above our front door. The neighbor already put plastic panels over their part of the roof, so I decided to skip painting, and also install similar panels.

What the underside of the roof looked like

These panels fit together

You start by mounting this bracket that the first panel slides in to.

This rail will hold a cover that will go over the gap between the panels. The black marks are from my rubber hammer that I used to tap this rail into place.

Fix your own carkey

Wed, 06 Aug 2025 20:10:55 +0200

A few days ago the unlock button of my car key broke. The outer part of the plastic housing above the button fell off. “I know!” I said. “I’ll just fix it myself, how hard can it be?”

These are the steps I thought I would have to take:

buy new key housing online.
open old key housing and remove electronics and key
put in new housing
Done!

The tools I thought I would need were:

Text Classification

Tue, 24 Jun 2025 09:56:06 +0200

Over the years I have given many presentations about how to use machine learning to classify text documents. I wanted to create a notebook that would serve as a template for such presentations, allowing me to quickly demonstrate the process of text classification using machine learning techniques. The problem of text classification is a common task in natural language processing, where the goal is to assign predefined categories to text documents based on their content. This notebook demonstrates how to classify documents from the 20 Newsgroups dataset using a decision tree classifier. We will preprocess the text data, extract features using a bag-of-words model, train a classifier, and evaluate its performance.

Vibe-Coding Pim Pam Pet

Tue, 13 May 2025 14:58:14 +0200

Pim Pam Pet is a Dutch game that is played with cards. The game is played with a deck of cards that have different categories on them, such as animals, countries, and colors. The goal of the game is to collect as many cards as possible by being the first to shout out a word that fits the category on the card.

Pim Pam Pet

Playing a word game with colleagues reminded me of the game of Pim Pam Pet. I wanted to give vibe coding a try again to create a version of it on my own site. This time I tried a Gemini model, because it’s included in my Google subscription. The model itself would not tell me which version it was, but in these release notes I found it’s probably Gemini 2.5.

Bricks and Tables

Thu, 17 Apr 2025 11:31:51 +0200

A nostalgic memory of a multiplication tables game from childhood inspired this project. I looked at the national archive for dutch educational games but could not find it. So I decided to recreate it for my son and use this opportunity to explore coding with Copilot. This project aims to build a web-based game from scratch, despite my limited experience with JavaScript and game development. The model I used is OpenAI’s GPT-4o.

game

Thu, 17 Apr 2025 11:31:51 +0200

Multiplication Game

Time Left: 60s

Talentuur resultaat

Wed, 26 Mar 2025 16:20:58 +0100

this page is only in dutch.

Talentuur

Mon, 27 Jan 2025 16:07:35 +0100

I’m teaching a short course on programming and AI for middle schoolers. called a “talentuur”, (Talent hour).

link to the course

My goal with the talent hour is to introduce high school students to programming and AI. I choose the programming language Python for this because it is the language I have the most experience with, the syntax is easy for beginners to learn, and it is a widely used language for AI-related projects. I plan to reuse as much existing course material as possible. This is easier for me, but it also ensures that the students become familiar with several online platforms where you can learn for free.

Sunwane Island DND adventure

Sun, 22 Dec 2024 14:44:08 +0100

A weekend together with my old group of adventurers in a familiar vacation cottage below Groningen. The imagined Sunwane Island was the real destination as we embarked on a fantasy quest.

The boys taking a break on a hunebed

Preparation by the Dungeon Master

I was the dungeon master again this time, and prepared an adventure on a tropical island with a twist. I started with a quick draft of a plot, and shared it with the players. In the meantime I prepared the rest of the story for the twist. Previously our group played the DND5e Dark Matter sci-fi setting and really enjoyed it. After last time though the others said that they would like to play some classic Forgotten Realms DND again. Since nobody else really wanted to be the Dungeon Master this time, I ended up volunteering. I told them I would prepare a typical DND adventure, but was planning to incorporate some Dark Matter in the story as well. I wanted the story to be about vacation, fun and reality. I wanted it to blend the traditional setting and sci-fi setting very well without giving away the twist.

Aigrunn2024

Fri, 29 Nov 2024 10:16:16 +0100

I visited the AI conference in Groningen called aigrunn. This article has some notes on the sessions I attended. These notes are primarily for my own reference and not very well formatted, sorry!

Going beyond tabular data with graphs

Talk by Chris van Riemsdijk from datanorth about graph neural networks. This talk was about data that can be organised as a graph. Graph Neural Networks called GNN’s transform graphs. The idea is graph in graph out, so some transformer on a graph that also produces a graph. This way information can be added to the nodes and edges of the graph.

Pydata Amsterdam 2024

Wed, 18 Sep 2024 09:25:30 +0200

This year I visited pydata in Amsterdam. Here are some of the sessions I visited with tutorial links, my brief thoughts on some keynotes, and a programming puzzle that really interested me.

Polars plugin in Rust

Polars is a dataframe library taking the world by storm. It is very runtime and memory efficient and comes with a clean and expressive API. Sometimes, however, the built-in API isn’t enough. And that’s where its killer feature comes in: plugins. You can extend Polars, and solve practically any problem.

Chess

Thu, 08 Aug 2024 14:18:13 +0200

I’ve recently started playing chess with my son. He’s just starting, so playing against him is very easy for me, even though I’m by no means a good chess player. In order to make the game a bit more fair, and thus more fun for both of us, I want to introduce a handicap for me. I found a table with handicaps¹ in the wikipedia chess handicap article. Based on this list I created the following 10 levels of play, where level 1 gives the player the most advantage.

FOSS piano learning

Sun, 23 Jun 2024 23:43:47 +0200

Recently I’ve started to learn to play the piano. There are a lot of resources available to start learning, but where to start? I remembered seeing a video of a kind of game where you could learn to play the piano. Synthesia as I found out it is called, is unfortunately not free, and also does not really teach sight reading. Therefore I considered it more of a novelty than a real learning tool, however fun it looked.

Advent of Code 2023

Sat, 18 Nov 2023 21:32:13 +0100

This year I intend to join Advent of Code again. While we wait to celebrate Christmas we can solve some programming puzzles together. This year I will join the ING leaderboards. You can also check out my solutions for Advent of code 2021, or see me publish my solutions for 2023.

aiGrunn 2023

Mon, 13 Nov 2023 21:42:37 +0100

This year I visited aiGrunn. I got the tip to visit this event from a coworker. When looking online I immediately recognized the art style from PyGrunn. Overall the visual impression and style was very well executed. I really liked how they integrated the Groninger word for egg (ai) into the design and opening talk. The audience was asked to hold an imaginary egg and respond to a series of questions with “ai”. The final question was a very relieving and self-aware “who’s tired of these questions?”

Contact

Wed, 01 Nov 2023 21:58:46 +0100

Alex Hamelink
alex@alexhame.link

Creating a Website

Wed, 01 Nov 2023 21:58:46 +0100

Freedom has taken on a new dimension in the information age. The internet has transformed the way we interact, share information, and express our thoughts. It’s a powerful tool that has the potential to connect us with a global audience, yet the concept of freedom in this digital world is not as straightforward as it may seem.

In the early days of the internet, often called Web 1.0, access to the digital realm was confined by one’s technical prowess. In contrast, today’s Web 2.0 era is marked by influential platforms making the internet accessible to a wider audience. However, this newfound accessibility brings its own set of constraints. These platforms, evolving over time, have adopted stricter content moderation and community guidelines. Though aimed at preserving order and safety, they have inadvertently curbed freedom of speech. These platforms, once synonymous with free expression, now dictate what’s acceptable to say, prompting concerns about stifled diversity of opinion and the openness of digital discourse.