I'm an entrepeneur, physisist, traveler and software engineer. Currently I'm focussed on building iPhone applications. Most of the time I'm in Utrecht, The Netherlands.

I'm a huge fan of the Lean Startup philosophy as explained by Steve Blank and Eric Ries. I strongly believe in keeping things simple and to an absolute minimum. If your product is not a success you've saved money and time this way. If it is, there's still plenty of time to make it bigger.

Interested? Please contact me at info@purpledunes.com.

You find also out more about me on my personal blog and personal twitter account.

Kangxi Radicals

Are you looking at a Chinese restaurant menu with no idea what you're about to eat? It used to take a lot of skill to lookup a character in a dictionary. With this app however, you can identify up to a thousand characters in just three taps! You don't have to learn anything.

The app tries to download human pronunciations from Forvo and when it doesn't find one or when the connection is too slow it uses the speech synthesiser built into iOs 7.

You can buy it in the App Store or try the free Lite or web based versions. I use the latter to quickly try out new features before I go through the effort of implementing them in the native app.

Technologies: iOs 7, Ruby on Rails.



Bitcoin for Passbook

Keep track of your bitcoin expenses right from Passbook. That includes notifications for new transactions. There's no app involved and users don't even need to use their iPhone to make the purchase. This is my own project.

Purchase for just 0.01 bitcoins at bitcoin-passbook.com

Technologies: iOs, Passbook, Ruby on Rails, Bootstrap, Coinbase (similar to Paypal)

Brink Licht

Browse through Brink Licht's inspiring collection of design lights on your iPhone or iPad. I created this application for Brink Licht.

Download it for free in the App Store

Technologies: iOs



Fungo Holland

Buy museum tickets right from your iPhone. I created this application for Reen Media B.V.. Tickets are stored in Passbook.

Download it for free in the App Store

Technologies: iOs


Practical clinical wisdom for doctors. They can share best practices and comment and vote on them, in a manner similar to Quora. This web application works on the iPhone as well as - perhaps you've heard of it - Internet Explorer 7. I built it for and together with Dr Pieter Peach who is based in Melbourne, Australia.

Visit the Website to watch a video demonstrating microvascular decompression.

Technologies: Ruby on Rails, Sphinx search, jQuery and Heroku hosting.




Only a native Chinese speaker can tell you if your pronunciation is any good. After you pronounce a word, it is sent to a real Chinese person. This was my own project. I hired teachers on Elance and they checked for new student pronunciations every day. I even met up with them when I visited Shenzhen in 2011. It never took off unfortunately.

No longer available in the App Store, but here's a short video of an early prototype.

Technologies: iOs push notifications, in-app purchase and Ruby on Rails.

Utrecht Walking Tour

Take a walk through my city, hopefully without ever having to pull out a map. The app tells you where to go next and detects when you get there. This was my own project that I created after spending too much time abroad.

Behind the scenes I created a web based editor that allowed me to pinpoint the sights on a map, upload photos, crop them and then download the images for both the normal and retina screen.

Visit the Website or purchase it download it for free from the App Store.

Technologies: Ruby on Rails and iOs