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Smartwatch on Willem's Blog

Developing a native iOS app

Making a cycling and running tracker

May 11, 2024
How hard can it be to build your own cycling and running workout tracker app using native code with some help from AI? Read along to find out!

As a little side-project, squeezed between my normal work, I have been working on something of personal interest: a native workout tracking app for iOS. I wanted to make my smartwatch obsolete, instead using my phone to track workouts. How hard could it be to gather detailed sensor data using native Swift APIs?

Half Marathon

On Training, Data and Feeling

Mar. 24, 2024
Discover my journey from noob to (half) marathon finisher and how I balanced data with fitness - read about my experiences!

Last Sunday, I participated in the Venloop, a half marathon event in Venlo. I completed the 21KM run in 2h05, a result I am satisfied with as this was my first ever 'official' event since I began running just three months ago. In this post, I'll share my experiences with training, balancing fitness data, and feeling fit.

Apple Watch as Phone

Replace your smartphone with a smartwatch

Nov. 10, 2023
Embark on a digital detox journey as I swap my smartphone for an Apple Watch Ultra, exploring the liberating yet challenging world of wearable tech.

Imagine a week without your smartphone, replaced solely by the sleek simplicity of a smartwatch. This week I did this, leaving my smartphone behind and letting an Apple Watch take the helm. Many hail this as a liberating escape from our attention-seeking digital sidekicks, but does it truly live up to the hype? Join me on this intriguing journey, where technology meets minimalism, and discover whether less really can be more.

Rolex DateJust 36

A crown for every achievement

Dec. 22, 2022
Celebrating a major milestone, I treated myself to a Rolex DateJust 36. Want to know what it's like? Keep reading!

The year 2022 has been very special to me, after working very hard to make it possible: me and my family finally made the big move to Limburg. To commemorate this milestone, I got myself a timeless timepiece: the Rolex DateJust 36. Read on to find out what it's like!

Wearing WHOOP 4.0

Why you should wear a biometric sensor

Jan. 14, 2022
Use WHOOP to see the impact your choices have on your body, think of it as a special kind of mirror - it's so powerful, that I don't take mine off!

How often do you look in the mirror? Probably more than a few times a week! I have been thinking about this ever since I received my newest WHOOP 4.0 biometric sensor. It's great. But, why do I wear it? What value does it provide? Why should you wear it?

Wearing Grand Seiko

On craftsmanship, innovation and practicality

June 5, 2021
I am glad I took the opportunity to wear a Grand Seiko, learning first hand about its craftsmanship, innovation and practicality.

Sadness could be seen in my eyes when my custom made watch got damaged earlier this month, while awaiting repairs I was fortunate to wear a Grand Seiko. Its unique mix of craftsmanship, innovation and practicality is worth sharing with you.

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.

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.

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.

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.

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.

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!

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.

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.

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.

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?

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?

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.

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.

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!

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.

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!

All blog posts
Timeless timepiece: an annual calendar watch, custom made to my specifications
Timeless timepiece: an annual calendar watch, custom made to my specifications
The Apple Watch Ultra 2 is a great little training companion, enabling the tracking of many different types of workouts; like cycling and running
The Apple Watch Ultra 2 is a great little training companion, enabling the tracking of many different types of workouts; like cycling and running
Mechanical watch and Apple Watch
Mechanical watch and Apple Watch
The watch feels at home in and around the pool
The watch feels at home in and around the pool
Wearing your watch on a different strap can make it feel like an entirely different watch
Wearing your watch on a different strap can make it feel like an entirely different watch
In my average-sized hands, the watch is just the right size
In my average-sized hands, the watch is just the right size
Not your average debugging session: Fietselfstedentocht 2024
Not your average debugging session: Fietselfstedentocht 2024
The case is milled with extreme precision, making it unnecessary to hide mistakes by polishing (as there aren't any!)
The case is milled with extreme precision, making it unnecessary to hide mistakes by polishing (as there aren't any!)
Opening the watch can be done using a special tool
Opening the watch can be done using a special tool
Replacing the original metal bracelet for a nylon NATO strap
Replacing the original metal bracelet for a nylon NATO strap
Comparing Apple Watch Ultra 2 with a Rolex DateJust 36MM
Comparing Apple Watch Ultra 2 with a Rolex DateJust 36MM
HealthFit is a fantastic app offering you detailed insights of the workouts you record with your Apple Watch, WHOOP, Garmin, Wahoo or any other app that supports Apple's HealthKit
HealthFit is a fantastic app offering you detailed insights of the workouts you record with your Apple Watch, WHOOP, Garmin, Wahoo or any other app that supports Apple's HealthKit
Set up UptimeRobot to detect the text that you expect when the service is online
Set up UptimeRobot to detect the text that you expect when the service is online
The Trend Is Your Friend: using WHOOP I tracked my trends, here you see that I have increased the training load (strain) over the past 3 months leading up to the Marathon
The Trend Is Your Friend: using WHOOP I tracked my trends, here you see that I have increased the training load (strain) over the past 3 months leading up to the Marathon
This watch has an automatic Citizen 6000 movement with 21 jewels
This watch has an automatic Citizen 6000 movement with 21 jewels
Early prototype of the app working with Bluetooth heartrate sensor and its early dataset shown in another app that makes some pretty graphs (HealthFit)
Early prototype of the app working with Bluetooth heartrate sensor and its early dataset shown in another app that makes some pretty graphs (HealthFit)
The box contains three straps, charging cable, charger and two sensors
The box contains three straps, charging cable, charger and two sensors
Server hardware inside a rack in the data centre
Server hardware inside a rack in the data centre

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