# Hi 🐒🌱🌍

My name is Joost – I am an engineer and this is my digital garden where I write sometimes about things that interest me. Also I keep lists of books I have read 📚 and things and tools that I use 🔧.

I am completely into drums 🥁 and espresso ☕.

## Some hatch mechanics 📐🔨

I am often a DIY’er and I have a really heavy hatch (32 kg) at home that I want to open automatically with an electric actuator. Something like the hatch in the image below. You can buy these actuators for 50 to 100 euros online: but which one do I need? or: What is the minimal and maximal length (and stroke) that I need? What is the force the actuator should be able to push?...

January 20, 2023 · 2 min · 385 words · Joost

## Collecting stickers 📷

My local supermarket runs a campaign where you can collect stickers for a photo album 📔 with historic pictures of our pitoresk town. For every 10 euros you get a package of 4 stickers and in total there are 229 unique stickers. My question is: How many stickers including doubles do you need to get a full album? 💁 This is known as the Coupon collector’s problem (a variant of the birthday problem)....

January 1, 2023 · 2 min · 321 words · Joost

## Skiing in the Alps

While skiing in the Swiss Alps last winter, I got into a discussion about speed. Following my engineering knowledge, your skiing speed does not depend on your own mass. Without the intention to offend anyone, skiing is basically a form of falling at an angle. We can build a model based on Newton’s second law where acceleration times mass is equal to the resultant force. We can see that mass ($m$) will drop out of the equation:...

September 23, 2022 · 5 min · 907 words · Joost

## Overview of Spark configurations

Find myself looking for an overview too often. So let’s create a rough overview of common used config for Spark. As a start, create a Spark Session with default config: from pyspark.sql import SparkSession spark = SparkSession.builder \ .master(SPARK_MASTER) \ .appname("app name") \ .getOrCreate() The Spark Context represents the connection to the cluster; communicaties with lower-level API’s and RDDs. Some resource settings on the driver: ... .config("spark.driver.memory", "8g") ... .config("spark.cores.max", "4") ....

November 8, 2021 · 3 min · 431 words · Joost

## Local development on Rancher Desktop

Through Hackernews I found out about the recent release of Rancher Desktop and I was curious if this would be a good alternative to Docker desktop for the develop of web applications on my local machine. I don’t really have a problem with Docker desktop, just good to try something new every now and then and it is open-source. Running some containers really gets some steam out of my Mac so hopefully it has some improvement there....

October 16, 2021 · 2 min · 349 words · Joost