willem.com

Willem's Blogby Willem L. Middelkoop

Art of visualisation

Creating mouth-watering food photos

Mar. 26, 2021
You learn from experts if you have the privilege to work with them, this month I had a chance to help a professional food photographer.

You learn from working with experts and this month I had the privilege to work with a professional food photographer, my brother. Together we set out to photograph the entire menu of Café Carbòn in Amsterdam, enjoying the fabulous food afterwards. Read along for some food photography takeaways!

Three tips to make a content strategy work

Maximise the effect of your writing

Mar. 25, 2021
Consider these three things to maximise the effect of the words you write for your website, blog or company.

When you write for your blog or for your company's website, there are things you can consider to maximise the discoverability, longevity and impact of your writing. Leverage the energy you put in into your words. Today I share with you three of my lessons learned while writing for this website.

Wearing two watches

Both a mechanical and a smartwatch

Feb. 28, 2021
Why you should wear two watches, don't choose between a mechanical watch and a smartwatch!

For the past weeks I have been wearing two watches, and boy this is a thing! I love my mechanical watch, but I needed the modern connectivity of a smartwatch. I couldn't choose between them, so I decided to wear both. It's not as bad as you think, let me share some thoughts on my experience.

The value of notifications

How to setup your smartphone to save time

Feb. 22, 2021
It's easy to dismiss your phone's notifications as something that disturbs you, but if you take the time to set them up correctly, notifications can actually save you time!

It's easy to dismiss your phone's notifications as something that disturbs you, something annoying. But if you take the time to set them up correctly, notifications can actually save you time in the long run. Gain more focus by taking control over your online connection to the world. Read along for some tips!

Realtime service uptime monitoring

Discover problems before your customers do

Feb. 2, 2021
Downtime happens and it is nothing to be ashamed of, just make sure that you set yourself up to discover problems as soon as possible! Know about problems before your customers do!

Downtime happens and it is nothing to be ashamed of, just make sure that you set yourself up to discover problems as soon as possible! You can use realtime uptime monitoring to automatically keep an eye on your servers and services. Read along to find out how.

Building a product platform

Designing for reusability, flexibility and extensibility

Jan. 31, 2021
Leverage platform capabilities to quickly launch new products, designing for reusability, flexibility and extensibility.

This month I am leveraging platform capabilities to launch a new product. Over the years I have developed the "Lemmid" platform, a set of building blocks that allow me to swiftly develop new products. Designing a platform takes some extra considerations, but if you follow some simple rules you can do it yourself!

Abandoning my own tablet OS

Why I moved back to iPad and the Mac

Jan. 14, 2021
After a year of experimenting with Debian GNU/Linux on a Surface Go 2 I have returned to iPad Pro and the Mac.

The past year I have been experimenting with creating my own tablet operating system using Debian GNU/Linux and the i3 window manager on a Microsoft Surface Go 2 with LTE. After months of intense use I have now decided to abandon the experiment to move back to iPad Pro and the Mac. Read along to find out why.

Commuter bike checkup

How is my commuter bike doing after 21.000KM?

Jan. 10, 2021
This week my trustworthy commuter bike started making strange squeaking noises when braking, time to have a look at the bike after 21.000KM!

This week my trustworthy commuter bike started making strange squeaking noises when braking. It has been just over three years since I started cycling on it. People frequently ask me how the bike is performing and how the Gates Carbon CDX belt drive is doing? Time to have a look at the bike after 21.000KM!

Working with special hardware from China

On developing software without a manual

Dec. 31, 2020
This month I reversed engineered my way into developing software for a Chinese Android device with an embedded printer!

This month I received a shipment from China containing some special hardware, Android devices with embedded printers! To make life easier for the restaurant and business owners that use my food ordering app, I want these devices to automatically print new orders. If only I can get these machines to work with my software... challenge accepted!

Why Apple Silicon is a big deal

Blown away by a MacBook Air

Dec. 15, 2020
Never have I been so blown away as by the new MacBook Air with M1 processor. It is a big deal.

Apple now designs its own processors and I had a chance to work with the very latest from Cupertino: a brand new MacBook Air with M1 processor. Never ever have I been so blown away by a MacBook Air, pun intended. Let me share some thoughts why I think Apple Silicon is a big deal.

Designing a multi dimensional capacity queue

Managing kitchen-, delivery- and pickup capacity

Dec. 2, 2020
Dealing with a capacity queue is challenging, but if you take the time to model it right it is possible to create a performant and reliable system.

This month I needed to create additional dimensions to a capacity queue mechanism. The food ordering app that I created needed to be able to restrict capacity based on the number of orders, the contents in individual orders and the dispatch type (takeaway/delivery). Read along to find out how I used a Lambda Architecture to do this.

Designing my own watch

Timeless timepiece, both functional and comfortable

Nov. 30, 2020
Last month I received my custom made wristwatch from Switzerland, it is a minimalistic mechanical annual calendar designed to be understated and true to the metal.

Last month a very special package arrived from Switzerland, containing my custom made wrist watch. I decided to sell all my big brand watches and have them replaced by something unique, tailored to my personal preferences. This is the story of my watch.

Replacing a Shimano shift cable

Fixing the cargo bike after hunting for bears

Nov. 22, 2020
After some adventure with our cargo bike, the Shimano Nexus 7-speed shifter cable got damaged and needed replacement. Read my blog post to learn how to do this yourself.

Last week my son and I where looking for bears in the local park... a child's fantasy is priceless! Unfortunately, during some off road riding with our cargo bike, one of the cables got tangled up with a sturdy branch! Our wounded carbo bike was in need for a repair!

The joy of a simple laptop

Surface Laptop Go with Windows 10

Nov. 3, 2020
This week I tested the Surface Laptop Go with Windows 10 and quite frankly was amazed by the experience!

Every now and then I switch my gear to keep a tap on what is going on outside my regular tech habits. You’ll be amazed by what you can learn from trying out different things. This week I had a chance to test the Surface Laptop Go running Windows 10. Quite frankly, it amazed me!

Increase traffic to your blog with a RSS feed

How to setup RSS/Atom using NodeJS

Oct. 31, 2020
Using NodeJS I added RSS feeds to my blog as support for feeds can still provide you with value. Read about the

Writing for my blog has been a lot of fun, I receive messages from all of the world about the things I like. Traffic is growing, every month more readers are finding their way to my blog. This week I received a request to support RSS feeds on my blog. I wondered, are RSS feeds still relevant today?

How to use rsync to make backups

Explaining a powerful file transfer tool

Oct. 30, 2020
In this post I'll explain how to use rsync to transfer files to another computer system in an efficient manner, suitable to be used in a backup script.

It is very important to make backups of your data, as you never know when disaster strikes! One powerful, cross platform, tool to help you achieve this is 'rsync'. In this post I'll explain why rsync is useful and how you can use it to set up your own backups.

Rescuing photos from a crashed iMac

Using advanced tools to read files from a faulty disk

Oct. 15, 2020
This week I attempted to recover two decades of personal photo history from a crashed iMac.

This week I received a message from someone with a iMac that crashed. It contained more than 50.000 photos, covering two decades of personal history. As there was no backup, it was up to me to attempt to safe as much as I could. Could I possibly recover the personal photos?

Riding with Omata One

Analogue cycling computer with GPS

Sep. 29, 2020
If you're looking for an alternative for common cycling computers, the Omata One is something truely special: it indicates your speed, distance, ascent and time ridden using mechanical hands!

For the past week I have been riding my bicycle with Omata One, a special bike computer. Its mechanical hands indicate speed, distance, ascent and time ridden measured using precise GPS data. It is fun, read along to know why.

Refining my tablet OS experience

Using Surface Go 2 with 4G/LTE, Debian GNU/Linux and i3wm

Sep. 28, 2020
Installing Debian GNU/Linux on a Surface Go 2 with LTE/4G to replace my iPad Pro as daily driver.

Earlier this year I tried to create my own tablet operating system by installing Debian GNU/Linux on a Microsoft Surface Go tablet. I learned a great deal about what I like about tablets. But I still preferred my iPad Pro, mainly because of its polished user experience. This time I set out to refine my tablet software to replace my iPad.

Syncing files seamlessly between smartphone and tablet

Using unison to automatically sync between GNU/Linux and the iPhone

Sep. 16, 2020
In order to optimise my workflow, I was looking for a way to seamlessly access the same files on both my computer and smartphone. Read along to find out how I did it.

In order to optimise my workflow, I was looking for a way to seamlessly access the same files on both my computer and smartphone. This is useful to when you want to quickly send files from your computer using your smartphone through various messaging apps and vice versa. Read along to find out how I did it.

Free from the iCloud: Escaping Apple Photos

Using offline photo library management software

Aug. 31, 2020
Recently I freed myself from Apple Photos, using free software to manage my photo library. Read along to find out what software I use and how to make it play nice with your devices.

After encountering the umpteenth ‘magic’ bug while managing my iPhone’s photos, I was done with it. Apple came a long way since it launched iPhoto (the predecessor of iCloud Photos). But for something as valuable as my personal memories, I want to be in full control. Read along to learn how I migrated my photo library away from the iCloud, using free, open source software.

Cleaning a vintage watch

Rediscovering old beauty under layers of dirt

Aug. 23, 2020
This week I cleaned an automatic vintage watch and fitted it to with a new strap, rediscovering old beauty underneath layers of dirt!

This week I was cleaning my closet when I found an old watch. It came from my grandfather’s house. It looked like it had an adventurous live, full of wear and tear. I recognised that it had an automatic mechanical movement. Upon picking it up it almost instantly started running again. I wondered how cool it would be if I would gently clean it.

The best keyboard for iPad

Smart Keyboard Folio vs Magic Keyboard

Aug. 11, 2020
While everybody is raving about the Magic Keyboard there is something to be said for the

The tablet is at the frontier of mobile computing and its hardware form factor is evolving. This year Apple introduced a new Magic Keyboard for iPad that includes a trackpad. Everybody is raving about it, yet I think there is something to be said for the "mouse-less" Smart Keyboard Folio. Read along for some key differences.

Influencing purchase behaviour

Applying behavioural sciences principles to the purchase decision process

July 31, 2020
For my work I am continuously looking into scientific sources to improve e-commerce performance, conversion rates and online revenue. Use this useful report to apply behavioural sciences principles to your advantage.

This week I stumbled upon a brilliant report on how people make their purchase decision. For my work on the online food order app I am continuously looking into scientific sources to improve performance, conversion and online revenue. This report by Google discusses six biases influencing decision making. It's worth reading their full report, let me explain why.

Upgrading a 27-inch iMac 5K to 14 terabytes

Replacing the Fusion Drive with both a SSD and an harddisk

July 30, 2020
This month I nearly destroyed my iMac during an attempt to upgrade it. Thanks to determination and some spare time I was able to resurrect it from the death!

This month I did an attempt to upgrade my 27-inch iMac 5K. I wanted to replace the fusion drive with a SSD and a large hardisk. In addition I decided this was a good time to upgrade the RAM memory as well, maxing it out at 64GB. I was on a mission to create the ultimate iMac, but things didn't go to plan!

Repairing a Giro AEON bicycle helmet

How to replace the Roc Loc 5 system

July 9, 2020
Try fixing your Giro bicycle helmet? I went through some trouble to do it! Read along to find out how.

This month my trustworthy Giro Aeon bicycle helmet broke down! Normally I wouldn't hesitate to invest in safety and thus buying a new one. But I like the Aeon helmet so much that I went through some extra trouble to fix it. Read along to see how I did it.

Some thoughts on touch screen user interface design

Creating intuitive natural interfaces

June 24, 2020
I am working on a new app involving personal health that requires a natural intuitive interface that works well on touch screens. It's good to check out some best practices for touch UI design

Past weeks I have been working on a new app involving personal health. The main challenge is to come up with an intuitive, natural interface that works well on small touch screen devices. But what is it that makes an touch screen interface any good? Read along for some best practices.

Tudor Black Bay 36 long-term review

Six months on the wrist

June 17, 2020
For the past six months I have been wearing the same watch, every day and night. Read along to learn what makes the Tudor Black Bay 36 the perfect every day watch.

For the past six months I have been wearing the same watch, pretty much every day and night. It's a Tudor Black Bay 36 watch in steel, with a black dial. I like minimal (yet functional) design that lasts, this watch certainly ticks the right boxes. Read along to find out how wearable a smaller watch is in daily practice.

Linking Lemmid Store with kitchens

Integrating with external systems that you don't control

June 12, 2020
Designing backend servers to connect with external services is challenging as you need to take into account unreliability and unpredictability.

As part of the food ordering app I am building, I needed to design a reliable way to link the app to external systems. These external systems are beyond my direct control and include different checkout registers, kitchen management systems and ticket printers. Read along for more on designing for the unknown and unreliable.

Different ways to visualise health

Looking at games and fitness apps

May 25, 2020
To better understand how to visualise health I looked at different health/fitness apps and games.

This month I did some research into how health is visualised in fitness apps and games. For a new app involving personal health I am looking for an intuitive way to visualise how healthy one person is. There are many colourful approaches out there!

Scalable application design without magic

Leveraging client computing power for high performance with many users

May 11, 2020
I needed to design a scalable backend infrastructure that could handle lots of concurrent users. I did this by leveraging the client's computing power having it handle most of the user interaction workload.

As part of the online food ordering app I'm building, I needed to design a scalable backend infrastructure that could handle lots of concurrent users. Scalability is considered a hard problem to tackle. Often it's presented like it's something magical, done by million dollar companies using secret tools. But, there is no such thing as magic, or is there?

Designing an interface for a food ordering page

Striking a balance between powerful options and mobile usability

May 1, 2020
Designing a food ordering page is surprisingly challenging because of the many variables that need to be accommodated on a very small screen.

Online ordering pages are more important than ever before. The COVID-19 virus, the resulting lockdowns and the social distancing rules have emphasised the need for a well-designed webshop user interface. This is surprisingly hard to get right!

Minimalistic road bike with Gates carbon drive

Meet your new therapist: the Schindelhauer Siegfried Road

Apr. 30, 2020
For the past few months I have been riding the Schindelhauer Siegfried Road bike with the Gates CDX Carbon Drive, read about this beautiful minimal bike in this post.

For the past few months I have been riding a special kind of bike, the minimalistic Siegfried Road from Schindelhauer. It is unlike most road bikes as it lacks a conventional chain and derailleur. It features the Gates CDX carbon drive. It's an exercise in minimal design. After riding it for nearly 1000KM, it's time to tell you all about it.

Talking tablets: what makes a great tablet?

Working with Microsoft Surface Pro X

Apr. 14, 2020
Over the past few weeks I worked with Microsoft Surface Pro X to see if it is any good, can it be your main computer?

Earlier this year Microsoft released their brand new Surface Pro X tablet computer, in many ways this is a forward thinking device. As I like working with tablets I wondered what exactly makes a great tablet? Is Surface Pro X any good? Read along to find out.

Traffic shaping using iptables and tc

Limiting outbound network bandwidth per client IP-address

Apr. 1, 2020
This month I responded to an automated alert indicating excessive bandwidth usage on a server, requiring me to apply traffic shaping to mitigate the traffic.

Last month I received an automated alert indicating excessive bandwidth usage, usually a sign of trouble. When this happens, you should follow a standard incident procedure, trying to isolate the source of the traffic before shutting it down. The cause of this incident was not what I expected however... requiring a different kind of mitigation than a simple blockade.

Designing and implementing a (micro) payment system

Monetising my blog with coffee, Apple Pay and Mollie

Mar. 25, 2020
Designing and implementing a micro payment system with an emphasis on simplicity. Read about how I did it in this post.

Online payments are now more important than ever as businesses are disrupted by the COVID-19 virus. It drives my customers to seek new ways to make money online. I designed and implemented a (micro)payment system. This post is about achieving simplicity by solving complex challenges.

Making my own tablet OS

Installing and modifying Debian GNU/Linux on Surface Go

Mar. 9, 2020
I wondered if I could escape Windows by installing Debian GNU/Linux on a Surface Go, read along to find out how to do this!

For some years now I use a tablet as main computer, I like its versatility. But, most tablets come with a locked down operating system, like iPadOS, Windows 10S or Android. As I like things my own (weird) way, I wondered if I could escape these "software jails" by installing a free operating system on a tablet. It's possible, read along to find out how I escaped!

Monolithic vs Microservices software architecture

Choosing the right design for your app development

Mar. 3, 2020
This week I flew to Gothenburg to talk about enterprise software architecture, read along to learn about choosing the right architecture for your app development

This week I flew to Gothenburg to meet people from a large international shipping company, talking about the development of enterprise level software. During the meeting there were various experts in the room, one of them asked me on choosing the right software architecture (for big, complex, enterprise level apps). A very good question, well worthy for a blog post.

Your own addressbook and calendar cloud

Share contacts, agendas and tasks with CardDAV/CalDAV

Feb. 28, 2020
You can setup a CardDAV/CalDAV server to manage your own contacts, addressbook, agenda and task data and share it between your devices.

If you use different devices and computers to get things done, you might want to synchronise contacts, agendas and tasks. You can use any of the 'big cloud' services for this, like Apple iCloud, Microsoft Office 365 and Google Gmail. But, if you prefer not to share your addressbook and calendar with big American companies, you can do it yourself.

The day I sold my car

Looking back at my years with Smart Roadster

Feb. 13, 2020
This week I sold my car, I now no longer own one. I look back at my years of owning a sports car, if you're looking for a reason to buy one you should check this out.

This week I sold my car, I now no longer own one. For me, this is something of a change as over the years I owned various sports cars that were like a hobby to me. My discovery of cycling and the birth of my son changed this. But if you're looking for a reason to buy a sports car, read along!

Measuring cholesterol levels in blood

Know your LDL, HDL and Triglyceride numbers

Jan. 28, 2020
This week I had my blood examined to measure my cholesterol levels, taking a lipid profile. Know your LDL, HDL and Triglycerides numbers with a simple test.

This week I went to my doctor to have my blood examined, to determine my cholesterol levels. Over the past years I have been paying more and more attention to my health. After improving my lifestyle considerably, I wondered what my numbers were.

Improve your sleep by blocking light

On the benefits of wearing a sleep mask in bed

Jan. 24, 2020
I have been wearing a sleep mask in bed, blocking all light. It has been amazing for my sleep's quality. Read along for my findings!

Over the past few weeks I have been experimenting with wearing a sleep mask in bed, blocking all light. Our bodies produce the sleep hormone, melatonin, in darkness. Living in an environment awash in artificial light, is therefore exactly the sort of thing that disrupts one's circadian rhythm. Can a simple mask help?

Whoop strap review: 24/7 wearable sensor

Beyond fitness tracking and smartwatches

Dec. 31, 2019

The past months I have been wearing the WHOOP Strap 3.0, a wearable sensor that collects health and fitness data. It's different compared to most other fitness bands as it was designed with professional athletes in mind. It is focussed on daily strain, recovery and sleep. Read along to find out how this works.

Realtime human pose recognition through computer vision

Using TensorFlow and PoseNet on a video feed

Dec. 1, 2019
For an exciting new project I have been experimenting with TensorFlow, enabling realtime pose detection using PoseNet.

For an exciting new project I have been experimenting with computer vision using TensorFlow. I wanted to achieve realtime human pose detection to drive interactive video projections and games. Time to dive into the world of machine learning, tensors and computer vision!

Supernova E3 Pro 2 dynamo powered headlight

Replacing my bike's headlight

Nov. 26, 2019

Earlier this month my dynamo powered headlight on my commuter bike needed replacing. One of the electrical connectors broke of, likely caused by intense daily use. I searched for the best possible light, one that would be extremely durable and bright. I found the Supernova E3 PRO 2 and decided to install it on my bike.

Building a professional 72TB NAS

Configuration and installation of an HPE ProLiant DL380 server

Nov. 22, 2019
This month I installed a professional HPE ProLiant DL380p server in a datacenter in Amsterdam, read this post to see how this was done!

Over the past few years I have been moving my data and work from local computers (mostly laptops) into the cloud. Cloud computing is done by servers in a datacenter, powerful computers that do the hard work. As my company grew, I needed more capacity. It was time to add some power to my cloud!

Flying in a C47-A (DC-3) classic plane

Aboard the 75-year old royal PH-PBA dakota

Oct. 19, 2019
Flying in a C47-A Skytrain over The Netherlands is one magnificent birthday gift I received, experiencing aviation history unlike anything else!

As a wonderful birthday gift I was honoured to fly in a DC-3 classic plane. It was the 75-year old PH-PBA, a C-47A Skytrain or Dakota, formerly owned by H.R.H. Prince Bernhard from The Netherlands. It's a very special plane operated by the enthusiastic people from the Dutch Dakota Association (DDA Classic Airlines). Read along for some aviation history!

Multi-Window support in your iPad app

Native development for iPadOS

Oct. 7, 2019
Take advantage of the improved support for multiple windows on iPadOS by implementing new UI concepts enabling different use cases for your app.

Last month Apple released iPadOS, the first dedicated operating system for iPad. It differs from iOS with its support for the larger iPad screen, including multi / split screen windows. I develop apps and it was time to take advantage of these new possibilities that iPadOS offers.

Visiting an international hackers conference

OWASP Global AppSec Amsterdam

Sep. 27, 2019
This month I attended Global AppSec Amsterdam, an international conference for hackers and security specialists. Read along for some of the highlights.

This month I was lucky enough to attend Global AppSec Amsterdam, an international conference for hackers and security specialists. There were presentations from former intelligence agents, bounty hunters, academics and software vendors. I learned about some of the newest hacking techniques, met with interesting people and played some cool retro games. Read along for more.

Fighting backscatter spam at server level

Configure Postfix to block spam before it enters the server

Sep. 10, 2019
Deal with backscatter spam by implementing a stringent SMTP delivery policy at MTA level.

This month I had to deal with backscatter spam, affecting one of the mail servers I manage. As server engineer I make sure that servers don't send spam and that incoming email gets filtered. Despite all good efforts, this server kept being blacklisted for sending spam to iCloud, Office 365 and Google Gmail for Business (G Suite). Read along to find out how what caused this and how to fix this.

Riding with a power meter on your bike

Installing and using the 4iiii Precision Powermeter

Aug. 28, 2019
In this post I describe my experience with installing the 4iiii Precision Powermeter on my road bike.

After I created a minimal road bike, I decided to install a power meter to find out what's it like to measure the power output of my legs. What can you learn from a power meter? Is it difficult to install? Is it worth it? Read along to find out.

Creating a minimal road bike

Recombining and refinishing old parts into a new bike

Aug. 18, 2019
I wondered how hard it would be to make a bike from spare parts I had in my garage

Over the past months I have worked on different bikes, leading to an accumulation of spare parts in my garage. I wondered how hard it would be to make a new bike using these spare parts. I decided to take advantage of this moment to refinish some parts, removing excessive decals in order to create a minimal looking road bike.

Limitations of sleep tracking using a wearable

Comparison with a chest strap HR-monitor

July 16, 2019
Limitations of heart rate analyses during sleep, why you should reconsider tracking your sleep.

Sleep monitoring is a popular feature of many smartwatches and wearables. Devices like Fitbit, Withings, Apple Watch and Biostrap analyse biometrics during your sleep. These wearables are worn on the wrist and use optical sensors to capture your heart rate. I wondered how the optical sensors would compare to a high resolution chest strap HR-monitor.

Optical vs chest strap heart rate monitors

Measuring beats per minute using different sensors

July 15, 2019
Understanding the differences in common HR monitors used in wearables, smartwatches and fitness trackers

With modern wearables, smartwatches and fitness bands, it has become easy and common to measure your heart rate. There are however fundamental differences in sensor types. Some sensors capture the electrical signal from your heart while others use light to analyse the blood flowing through your vessels. If you're interested in measuring heart rate, it's good to understand these differences.

Assembling a cargo bike

Setting up the Babboe Big cargo bike

June 25, 2019
How hard can it be to assemble a cargo bike? This posts shares my experience with assembling the Babboe Big cargo bike.

This month our Babboe Big cargo bike arrived, in boxes. The engineer in me thought it was a good idea to assemble the bike by hand. This way I would know exactly about all its parts and fittings, handy knowledge for maintenance. Read along for my experience and some practical tips.

Six months with MCADD

Thoughts and tips on the daily life as parents

June 24, 2019
It's six months since our son was born with MCADD, a good moment to reflect upon the experience of being a parent with some thoughts and tips.

Tomorrow it's six months since our son was born, a good moment to reflect upon the experience of being a parent of a kid with MCADD. This metabolic condition demands special attention on the feeding schedule and preparation for situations when things go different. It's good to share that this has quickly become normal for us, here are some thoughts and tips.

Solo around the Markermeer (211KM)

Tips to prepare, to endure and to enjoy long distance cycling

May 29, 2019
This week I took my bike for a long distance (211)KM ride around the Dutch Markermeer, solo! Read along for practical tips for long distance cycling.

This week I took my bike for a long distance (211KM) ride around the Dutch Markermeer, solo! Unlike participating in an organised event with service, support and company along the way, going solo requires a different preparation, mindset and planning. Read along for some practical tips for long distance cycling.

Dig for dummies

Explaining an highly useful network tool

May 24, 2019
Learn how to use the dig command to query domain name servers to find the source of network problems, IP-addresses, hostnames, mail servers and related info.

When you're building websites, apps or email services you may run into domain names and their configurations. When everything is working as it should, most of this is invisible. But when troubleshooting a domain name configuration, it may be necessary to dig a little deeper... read along to learn how!

The best bike computer app: Cyclemeter

Get advanced ride data with a flexible setup

Apr. 30, 2019
Collect advanced bike ride data using your smartphone connected to external Bluetooth sensors and a steer mounted display.

This month I have intensified my training to become fit for this year's Fietselfstedentocht, a 235KM bicycle ride through Friesland. Over the years I have tested different kinds of bike computer setups: from dedicated (and expensive) Garmin Edge bike computers to no data at all. Eventually I came up with a flexible setup to gather advanced ride data using my smartphone, let me explain how this works.

Search like a pro: Google search operators

Comprehensive list of advanced search operators

Apr. 25, 2019
Read along for a comprehensive list of advanced Google search operators that allow you to filter your search results.

You probably use the world's most famous search engine to find things everyday, but you might not know about some of its advanced search operators. You can use these special search phrases to find things that are otherwise burried in the search results. Read along for a comprehensive list of advanced Google search operators.

WordPress: 10 tips to secure your website

Keep hackers out of the world's most popular content management system

Mar. 31, 2019
A lot of people use WordPress to manage their website. Prevent your site from being hacked using this blog post.

A lot of people use WordPress to manage their website, therefore it's no surprise people ask me to have a look at their site's security. As ethical hacker, I encounter WordPress in different shapes, sizes and states. Some of them are really badly protected against hacks. Prevent your site from being hacked using these 10 practical tips.

Servicing a robot vacuum cleaner

My iRobot Roomba is now running for 8 years and counting!

Mar. 20, 2019
This week it was time for some maintenance on my iRobot Roomba robot vacuum cleaner. Read along to learn how I did it.

Back in 2011 I got myself an iRobot Roomba 555 robot vacuum cleaner to automatically clean my apartment. It's a little circle shaped robot that drives around sucking up dust bunnies. Over the years it has bravely fought the dangers of my apartment... shoes, cables, carpet and belts. It survived and it is still working perfectly! This week it was time for some maintenance.

Understanding the security concerns in shared hosting

Considering open ports and unused network facing services

Feb. 28, 2019
People pay me to hack them, provided I'll explain how I did it. Read along to learn how hackers use security holes to hack your app, webshop or website!

People pay me to hack them, provided I'll explain how it was done, so future hacks can be prevented. As security consultant, I scan for weaknesses in my clients' apps, webshops and websites. Very often a hack starts by exploiting a security hole that is visible remotely. Read along to learn how hackers find security holes and what you can do to secure them.

One year on the ultimate commuter bike

6000KM in 12 months with Gates CDN/CDX and Shimano Alfine

Feb. 27, 2019
Answering questions from one of the most popular posts of last year, I am reviewing my commuter bike after one year of extensive use through winter and summer.

A year ago I tried to create the ultimate commuter bike, a modified Sensa Cintura with the Gates CDN/CDX carbon belt drive. I received lots of messages from cyclists and commuters from all over the world. From the Swiss alps, France, Italy, Germany, United States and even "down under", Australia! You all wanted to know: how does the upgraded bike hold up?

Born with MCADD

Medium chain acyl-CoA dehydrogenase deficiency

Jan. 29, 2019
Our son was diagnosed with MCADD days after he was born. We experienced a metabolic crisis but were lucky to be just in time!

Just days after our son was born, we ran into trouble when our little man didn't want to eat anymore. Repeated attempts to feed him failed as he appeared to be too tired to drink from his mother. When we measured his body temperature we were shocked, only 33º Celsius! What followed was nothing less than an incredible emotional rollercoaster!

My first weeks as dad

On the challenges and rewards of being a father

Jan. 24, 2019
Last Christmas my wife gave birth of our son. It's a life changing experience to become a parent. Read along for my (biometric) findings and some practical tips.

Last Christmas my wife gave birth to our son, a little boy that would change everything! It's an incredible experience to become a parent, especially if it is your first kid. It introduces a whole new way of living, having to deal with regular feeding, caring and sleepless nights. Read along for my (biometric) findings and some practical tips!

Business in a bag

Using a waterproof backpack to fit my gear

Dec. 22, 2018
After much testing I have selected a bag and set of cases to fit my entire business, wherever I go.

Over the past few months I have been testing different bags and cases to fit everything I need to run my business. As I commute by bike, the bag needs to be waterproof. The problem with waterproof gear is that it is usually very bulky. I need my gear to be both portable and representative, a challenge worth a blog post!

Do amazing things with a focused mind

Taking an ice bath and swimming in the Amstel river

Dec. 6, 2018
Read about my experience during the workshop I got as a birth day present involving the Wim Hof Method.

Just when the temperature was a low 2° Celsius, I jumped in the Amstel river! While it was nearly freezing outside I went for a swim, just moments after I've taken an ice bath! This post is about the incredible birthday present I got, a workshop involving the Wim Hof Method.

Around town in an electric car

Driving the Smart Electric Drive (EQ fortwo)

Nov. 16, 2018
For one week I drove the electric Smart EQ fortwo in and around town. I found out what it's like to drive electrically: fun!

Earlier this month I drove around town for a week in an electric vehicle, a brand new Smart Electric Drive (EQ fortwo). I used it to commute, for my daily groceries and to visit family, friends and customers. What's it like to drive a fully electric car on a daily basis?

Is the Apple Watch the modern tool watch?

Testing the Apple Watch's usefulness in real life

Nov. 2, 2018
I tested the Apple Watch during my work in Frankfurt this week where I had to go inside an internet data centre.

This week I went to Frankfurt for business. I had to perform maintenance to servers in a data centre. This seemed like a great opportunity to test the Apple Watch's usefulness in real life (other than health and fitness). I wondered, is the Apple Watch the modern tool watch?

Rescuing files from a broken harddisk

Make backups to be safe rather than sorry!

Oct. 16, 2018
Yesterday I helped a young woman with her broken computer containing precious photos, could I safe them?

Yesterday a young woman brought me her laptop, it didn't start anymore and it only showed an error message. It turned out to be a broken harddisk. It startled her when I told her that all data on the disk was lost. She told me it contained precious photos of her pregnancy and young child. What could I do?

Using a budget Android as main smartphone

Comparing a Nokia (€99) with an iPhone (€1329)

Oct. 9, 2018
I switched to Android to find out how good a budget smartphone performs compared to an expensive iPhone.

Every now and then, I switch phones to keep track of mobile developments. As professional app and web developer, I need to know how different devices work in real life. This time I used a budget Android smartphone, making me curious how it would compare to an expensive iPhone.

Swimming and cycling with Apple Watch

Different activities in the workout app in watchOS

Sep. 27, 2018
This month I tested the newest watchOS while swimming and cycling.

This month Apple launched a new Apple Watch series and released an update to watchOS. The focus of the smartwatch is more and more gearing towards health and fitness. This made me curious, how well does Apple Watch work for different activities?

Optimising images for the web and performance

Reduce filesize with jpegoptim, optipng, pngcrush and pngquant

Sep. 26, 2018
Make your website faster by optimising the images. This posts explains how you can do this.

One way to make your website faster is to make it smaller. Not with tiny fonts, but with less bytes! More than half the weight of an average website is because of images. Yet very few people optimise their images for the web and performance, time to find out how much bytes you can safe!

Space travelling from El Teide

Visiting Tenerife's volcano at the Canary Islands

Aug. 21, 2018
On Tenerife you'll find Teide, the world's second highest volcano with extra terestial views and a perfect altitude for stargazing.

This summer holiday brought me to Tenerife, part of the Canary Islands, Spain. It's a popular destination because of the climate, but it's also the home of Teide, the world's second highest volcano (7500 m, measured from the sea floor). The incredible views reach way beyond earth, into outer space, the Milky Way and other distant galaxies.

Google Analytics vs AWStats

Understanding web traffic statistics software

Aug. 20, 2018
Comparing Google Analytics with AWStats to find out where they differ and which is better.

This month I have been working on website statistics, tracking traffic using different technologies. Some of my customers use Google Analytics, others use AWStats, and some use both. Which is better is often debated, but few people really understand the differences. Time to shed some light on the magic of web statistics.

Helping people with free software

Installing Debian GNU/Linux on an old laptop

July 20, 2018
This week I helped a man with repairing and reinstalling his computer with Debian GNU/Linux.

This week a man brought his laptop to the community centre where I help people with computer problems as volunteer. The old laptop wouldn't start anymore and had to be reinstalled. Instead of Windows, I installed a free operating system. I think it is important to tell you how and why I did it.

Enjoy a festival without alcohol

Alcohol-free beer at Rock Werchter

July 10, 2018
This year I didn't drink alcohol during Rock Werchter, leading to interesting observations during the music festival.

Last weekend me and my brother went to Rock Werchter, a multi-day, music festival in Belgium. Over 140 thousand visitors enjoy world famous artists like Pearl Jam, Nick Cave, Artic Monkeys, Noel Gallagher, The Killers and the Queens of the Stone Age. This year I didn't drink alcohol during the festival, leading to some interesting observations...

Removing paint from a bike frame

Uncover the aluminium with chemicals and sanding paper

June 9, 2018
Using dichloromethane and sanding paper I removed the paint from my bike frame to create a minimal, raw aluminium look.

There is beauty in raw, unfinished material that is often hidden with superfluous layers of paint. I like things to be true to the nature of the material. My bike was painted black - not bad - but I wondered what it really looked like from a material point of view.

Creating a minimal iPhone stand

Routing oak wood for a custom fit

June 2, 2018
Today I created a minimal iPhone stand from oak wood. I used a single piece of wood to get it done.

Today I created a minimal iPhone stand from oak wood. While it's much faster to buy one online, I wanted one to fit my phone horizontally, with its case on. I like minimal design, so I opted to machine a single piece of wood to get it done.

Listen to your body

Why I stopped using health and fitness sensors

May 17, 2018
Using health data gathered by sensors and wearables I learned to listen to my body. Now I have stopped using bluetooth sensors all together.

A good customer of mine was once a physiotherapist, he told me about people asking him to "feel their muscles" to tell them how they where doing. "Crazy!" he told me: "I can never feel better than the people themselves, if they only would listen to their body". This caused me to question the health and fitness sensors I use.

Lunch by plane

Flying from Hilversum to Texel in a Tecnam P2002JF

May 9, 2018
This week I went out for lunch by plane from Hilversum to Texel with a good buddy of mine.

This week I was invited to fly along over the Netherlands in a small aircraft, from Hilversum to Texel. A good buddy of mine is a pilot and planned to fly to the Texel island for lunch (and good fun!). The weather was excellent, so packed with my photo camera, I didn't hesitate for a moment to join him for lunch!

Off the grid: Working on 100% renewable energy

Collecting, storing and using solar electricity to power my phone, computer and wearables

Apr. 30, 2018
Learning from powering my personal devices using nothing but self generated electricity using a solar panel and power banks.

For the past 10 days I have powered my personal electronic devices (phone, computer, wearables) using nothing but energy collected using a small solar panel. I disconnected all grid-connected chargers. I hoped that by going off the grid, even in such a small way, I would gain insights that enable me to save energy (and money).

Outside the comfort zone: amateur acting

Wearing an heart rate monitor during my debut performance

Apr. 18, 2018
This month I strapped myself with sensors during a little experiment outside my comfort zone: I debuted as amateur actor!

This month I made my debut as amateur actor. I am no Hollywood star, nor do I envy to become one. But I do like crazy experiments and operating outside of my comfort zone often leads to new and refreshing insights. I took part in an amateur drama play and - in the name of science and fun - strapped myself with sensors to measure what happened to my body.

Cyber security: 5 easy tips to protect your server against hackers

Server hardening best practices for Windows and Linux

Mar. 10, 2018
These 5 practical cyber security measures will improve the safety of server, website and data.

This week one of my clients was hacked and asked me for emergency assistance to help secure their server infrastructure. It was a web server that ran WordPress websites on Apache (with PHP/MySQL), including a few webshops with customer data. This hack could easily have been prevented with the following best practices, is your server secure?

Tablet as main computer

Comparing the Microsoft Surface Pro to iPad Pro

Mar. 7, 2018
I have been using a tablet as my main computer for quite some time now. In this blog post I share you my experience on using Surface Pro and iPad Pro to get my work done.

For the past few weeks I have been using the Microsoft Surface Pro as my main computer. It's a modern tablet computer that can be used as laptop with the type cover. With the Surface Pen, it's a versatile PC that works in a lot of different ways. Time to find out if it's any good and how it compares to my other tablet computer, iPad Pro.

Creating the ultimate commuter bike

Riding at 35KM/h with Nexus Alfine 8 and Gates Carbon Drive

Feb. 24, 2018
Creating the ultimate commuter bike by upgrading the Sensa Cintura belt drive bike.

This winter I use a Sensa Cintura bike with a Gates Carbon belt drive as my daily commuter. It's a bike designed to be nice to ride thanks to its sporty lightweight frame. It's also meant to be low on maintenance thanks to the belt drive and Nexus Afline 8 integrated gear hub. After 1800KM in just eight weeks, it was time for some upgrades.

Updating Snake '97

About the challenges of developing a wildly popular game

Feb. 21, 2018
This month I bit the bullet big time: I redesigned the game engine of the wildly popular Snake '97 game. Read about the design challenges in this blog post.

Few years ago my brother threw a beer on my iPhone in an Amsterdam bar. The poor thing didn't like the Dutch brew as much as I do: it died. While waiting for a new phone to arrive, I used an old one that couldn't do anything but texting, calling and... Snake! The idea for Snake '97 was born and this month it was time to update the wildly popular game.

Something the smartwatch will never have: patina

Wear and tear by the hands of time

Jan. 21, 2018
Patina is often neglected when comparing smartwatches with regular watches.

A good friend of mine had an issue with his Apple Watch, the digital crown lost a rubber ring causing the watch to lose its water resistance. Apple made no problem of it and offered to replace his "device". While it solved his problem, it felt painful to my watch lover's ears. It made me realise the one thing a smartwatch will never have: patina.

Lessons from a takeaway plastic bag

My ever increasing antipathy to planned obsolescence

Jan. 8, 2018
How we're tricked into repeated purchases replacing perfectly fine products just for the sake of change.

About five months ago I got some take away food from our local Asian restaurant. They packaged the food and gave me a plastic bag to carry it home. On my way home I was thinking about the bag. Although it has some nice styling printed on it, it's designed for single use only. What a waste... making me wonder: how long would it last if you would use it on a daily basis?

Commuting by bike

One week (240KM) on the VanMoof Electrified S

Dec. 2, 2017
One week on the VanMoof Electrified S E-bike testing it for commuting and comparing it to a normal bike.

For a few years now, I commute to work using a bicycle. I have lost more than 15KG since I stopped using my scooter. This week I tested a VanMoof Electrified S, an electric bike with an industrial, minimal design. Is it any good? How does it compare to a normal bike? Will an electric bike make you lazy? Read along to find out!

Collecting health data with Biostrap

Wearing a clinical-grade photoplethysmography (PPG) sensor for a month

Nov. 15, 2017
Wearing a clinical-grade PPG sensor for a month to collect advanced biometrics from my wrist.

Most wearables (smartwatches, fitness trackers, etc.) use very basic sensors to capture heart rate. Their signal is binary: just counting beats. Biostrap is different, instead of just checking pulses, it captures a high-fidelity PPG waveform. These waveforms are the same kind that doctors use, making me wonder what I could learn from them!

From tree to table

Designing and creating a night stand

Oct. 23, 2017
Creating a night stand from a raw slab of chestnut wood.

Right next to the house were I was born there was this chestnut tree, sadly it died one and a half year ago. When it was taken down, my brother saved me a slab of wood. I intended to create something from it, a nice "do it yourself" adventure, worthy of a blog post!

Saving a MacBook Air with exploded battery

Don’t try this at home - but I did

Sep. 14, 2017
Saving a MacBook Air with a swollen battery pack.

Last night I had a nasty surprise: my original MacBook Air was swollen due to an exploded battery. I immediately had to take action, for reasons of safety and to preserve this piece of modern computer history. Don’t try this at home, but if you do... read along for some practical tips.

Climbing Mount Etna

Visiting an active volcano on Sicily, Italy

Sep. 2, 2017
Climbing Mount Etna, an active volcano on Sicily Italy.

Last week me and my wife went to Sicily for a little summer holiday. It is the largest island in the Mediterranean Sea. It is an autonomous region of Italy, along with surrounding minor islands. It's home to Europe's largest active volcano: Mount Etna. We had a chance to visit this lava spurring monstrosity and it was quite the experience.

Clouds below my floor

Building a little datacenter in my basement

Aug. 31, 2017
Building a little datacenter in my basement utilising a very fast internet connection.

At my home I have this crazy fast optical internet connection. It is a 600MB up and down fibre connection which directly arrives in my home (no copper cables involved). It's like a private internet highway. Reason enough to find out if I could do something to make better use of all this speedy fiber galore...

The day I killed my LAN

Turned off my local network and went 4G only

July 31, 2017
I killed my office LAN and went 4G only. Saves a lot of clutter, energy and money.

Today I called my provider to quit my office's ADSL internet subscription, I don't need it anymore. I have turned off my local area network and switched my workflow onto mobile internet only. The simplicity and savings actually surprised me so much, that I made blog post for it.

Fietselfstedentocht 2017

Cycling the 235KM bicycle tour through Friesland

June 30, 2017
Cycling the 235KM long Fietselfstedentocht through Friesland

This month I cycled the Fietselfstedentocht, a 235KM tour through Friesland. This tour brings you through various Frisian cities throughout one of the most Northern provinces of the Netherlands. The tour was first organised in 1912 and has grown to become legendary due to its history, challenge and popularity; well worthy of a blog post!

Beast of the Green Hell

Driving the Mercedes-AMG GT R

May 31, 2017
Blog post about an amazing AMG Circuit day at the race track of Zolder, Belgium.

This month I received an invitation to join Mercedes at the Zolder circuit in Belgium to drive in "the beast". The Mercedes-AMG GT R, a furious green coloured performance car that gets its nickname from the Nürburgring where it was developed. It was an incredible experience, well worth a blog post!

Smartwatches vs Mechanical watches

Why I still wear mechanical and why smartwatches have potential

Apr. 30, 2017
Why I still wear a mechanical watch and why smartwatches have potential.

Technology has come a long way since the first computer. Smartwatches today are very much an achievement of miniaturisation of technology. I recently used an Apple Watch Series 2 to find out if technology has come far enough to replace my mechanical watch, today I share you my findings.

Repairing a Nintendo Gameboy Advance SP

Chip surgery to play classic Zelda

Mar. 26, 2017
Reparing an old Nintendo Gameboy Advance to play classic Zelda again.

This month Nintendo released the Switch with Zelda "Breath of the Wild". The new console received positive reviews. The new Zelda game is amazing and can be played on-the-go, thanks to the portability of the Nintendo Switch. But it its hardly the first Nintendo device that features the mythical kingdom of Hyrule with Link and princess Zelda. I found an old Gameboy Advance, perfect for playing classic Zelda games... but it was in need for repair!

Programming on Apple Watch

Serious about crazy experiments

Feb. 16, 2017
Programming with VIM over SSH on Apple Watch using a bluetooth keyboard

Over the past years I have been no stranger to crazy experiments, but this time I really wanted to push it into the extreme: programming on an Apple Watch. Would it be possible to actually write code on such a tiny device? Why even bother? This post is about the case for crazy experiments, and why you should try too!

iPad Pro next to my primary machine

Using it with Apple Pencil as a creative powerhouse

Jan. 30, 2017
Using iPad Pro with Apple Pencil next to my computer to form a create powerhouse

I wanted see if I can find something better than my old fashioned pencil and paper that I use for designing software as professional developer. I knew iPad Pro from my test last summer, figuring out if it could replace my primary development machine. While it may not be able to completely replace my thrustworthy ThinkPad, it turned out to be a totally different story when it comes to paper.

One year of cycling

GPS recording an entire year of bike rides using Garmin and Strava

Dec. 31, 2016
GPS recording an entire year of bike rides using Garmin and Strava.

One year ago I started recording all my bike rides, including commutes, short grocery trips and long Gran Fondos. I equipped my bicycles with Garmin Edge computers that recorded location (GPS), speed, cadence and my heart rate. I covered more than 7683 kilometers during 320 hours of riding. It's time to review all the data and share some photos I took along the ride!

Being a volunteer in Amsterdam-Zuidoost

Computer support in the local community center

Nov. 21, 2016
About my work as volunteer in the local community center in Amsterdam Zuidoost

After realising how lucky I am as an healthy, well educated, young man with a solid income, I wanted to do something for other people as volunteer. It just so happens to be that two years ago I received a flyer in my mailbox from the local community center: they were looking for someone with some knowledge of computers. A very interesting journey was about to begin!

Harvesting boredom to let creativity flourish

using the Punkt MP01 dumb phone

Oct. 1, 2016
What does it mean for my state of mind and creativity if I am no longer be constantly connected to the Internet using a smartphone.

Smartphones are everywhere in the modern society we live in today. Through our 4G and WiFi connections the internet is just one tap away. In fact, it is so close that it feels like a natural extension. But is this wealth of information all good or does it have a downside too? It seems like an interesting experiment to go app-less for a while and solely use a dumb phone.

Batavus Champion bike from 1978

restoring retro glory with some help from the Internet

Sep. 3, 2016
Restore the retro glory of an old bike from the 70s using the internet.

Almost a year ago I bought an old steel racing bike from 1978. I wanted to figure out if using a bike to commute worked for me. It did! I used it to ride more than 1000KM before I decided to get a modern road bike. Now, almost a year later, I decided to put the powers of the internet into good use: to bring the bike back to its retro glory!

iPad Pro as primary computer

testing iOS as primairy development platform

Aug. 15, 2016
Is the time right to use an iPad as primary development platform to get some real work done?

The lack of physical clutter, distracting branding, or blinking LED's makes the iPad Pro a textbook example of minimal design. My despiction of distraction explains my interest in using the iPad Pro as only computer to test if it is up to the task. Is Apple's latest effort on iOS enough to enable it to do serious development work?

Cash is king, or is it?

The wallet- and cash-less experiment

July 15, 2016
Is the time right to ditch the wallet?

Very often I see men carry a wallet filled with plastic: multiple debit and credit cards plus a bunch of loyalty programs and membership cards. Then, some even top it off with stinky paper money and sticky metal coins! It made me wonder if I can free up one pocket by ditching the wallet?

Building the blog... in style!

Developing on a 20-year old computer with 16MB RAM and Windows 98

June 23, 2016
Find out if it is possible to turn a computer from the 90s into a modern development machine.

One must be a bit crazy to come up with the idea to build a blog (as in: actual programming) on an old 486 laptop with just 16MB RAM. I happen to be that crazy: I took my very first laptop from the 90s and decided to find out if it was possible to turn it into a development machine.