Been busy Blackstripezing…

January 19th, 2013

So long time no writing, but here’s a small update with what we were busy with for the last couple of months. The most important project on our own behalve, was: our DIY lineplotter project (build hardware as well as the software for this baby), first press coverage was with popular Dutch Magazine (digital technology, design & style): David Lemereis wrote a nice article about us. You can read all about that here (in dutch). Lately we were picked up by major tech site This gave us quite some exposure in the Raspberry Pi scene. Nice… on on

As you are picked up by a major site, news goes around fast and soon more blogs/websites are following (Adafruit, T3N amongst others):

Adafruit a major component supplier

Adafruit a major component supplier

German site T3N picked up on it too

German site T3N picked up on the news too

So what is this project all about? Blackstripes is our Robot which draws your pictures and you are able to purchase your own picture/photo as a drawing in the webshop as well!
Read more about it here:


Arduino Wireless Motion Tracker

June 25th, 2012

We have lately been working on some projects that involves measuring and interpreting  motion with inertial sensors.  We have done experiments with iPods, iPhones and other dedicated motion trackers.

We also tried to create a tracker on our own using the Invensense MEMS mpu-6050 chip. It’s a 6 dof inertial motion sensor with an embedded tri-axis gyro and tri-axis accelerometer and some kind of motion processing unit  on it as well. Getting the data from this sensor on our iPhone took al little more than just ordering this chip so we decided to use the Sparkfun break out board version, together with the WiFly shield featuring a Roving Networks wifi unit and put them both on an Arduino Uno. It took some fiddling to get the wiflly board  into adhoc udp mode, but now we were able to connect an iOS device on the adhoc wifly network and transmit UDP messages containing sample data from the mpu-6050. Using a tweaked GLGravity example xcode project as a data visualization tool we had a nice prototype of this little system. Right now we are able to get 20 captured samples per second over the air to the iPhone but it appears that by forcing the UART of the wifi unit into an higher baud rate (and also the UART baudrate on the shield itself) could easily increase the framerate. We haven’t tested this yet though.

Arduino Wireless 6-dof Motion Tracker

Arduino Wireless 6-dof Motion Tracker

As you can see in this photo I’ve soldered the mpu-6050 breakout board just beneath the wifly shield onto the prototyping section on this shield. To keep things nice and compact. In a practical situation it might be not ideal to have the chip upside down. Beneath you can see the board in action ;-)

openCV experiments

June 25th, 2012

Since we are currently not developing any new iOS game title we have some time to experiment with other things. Amongst others openCV on iPhone platform.

Because of the current ongoing EK soccer tournament we had our focus on football. More specifically tracking speed of a football. The concept is as follows:

Shoot a short video from somebody kicking a football (on a soccerfield), camera standing as perpendicular as possible to the assumed trajectory of the ball.

Then, based on the size of the ball in the videofootage as detected by openCV and the traveled ball distance from 2 frames in the video (recorded at a known time difference) in pixels. These pixel sizes recalculated to real life dimensions based on the known size of a typical football gives you the ballspeed. in kilometers/hour.

In theory this all sounds ok, but then we still have some practical issues to solve. First of all it turned out out that kicking the ball at fast speed (what real soccer players would do), skewed the ball enormously.

Skewed ball as caused by rolling shutter phenomenon

Skewed ball as caused by rolling shutter phenomenon

Here you can see some of the ball skewing

Here you can see some of the ball skewing. openCV "sees" the b/w filtered image

This is caused by rolling shutter artifacts see wikipedia. iPhone camera images are captured from top to bottom (landscape) line by line and not the whole frame at once. Because of this, a fast moving object will become skewed. openCV will not detect a circle when the circle is really skewed, so that’s the first problem.

Also when in low light situations, motion blurring, because of longer exposure times becomes an issue. The latest iPhone 4S support 1280×720 @60 fps which is the best bet when capping these frames. But even then motion blur can become an issue. Also ball detection is done based on the greenness of the grass. If your whitebalance is much to blue the conversion to black and white in opencv would fail. Of course you could adjust the tolerance for the detected hues but then you’re likely to run into many false positives for ball detections.

Much of these things/issues could have been fixed with some user input (let user select the correct ball, let user adjust filters for openCV based on some kind of wizard), but all in all it was a nice experiment but not good enough to make it into a proper dummy proof app. We basically didn’t want to make an app that expects all kinds of clever input from the user. We wanted the app to do some clever stuff and return you the speed of the ball without too much hassle.

opencv ball detection on the grass

opencv ball detection on the grass

Watermarker App update version 1.1 submitted to Apple

April 3rd, 2012
Main new feature fading

Main new feature fading

What’s New in this Version?

- Added watermark fading in and out options. With settable fade duration and fade – in/out point.

- Gui overhaul, changed the look of screen backgrounds and buttons. The glossy carbon look just didn’t cut it for me. I hope potential buyers agree with me it looks a bit more sophisticated now.

-Fixed some memory leaks

I hope it will be available soon, it has some nice added functionality. After this I will update CamLock with a bunch of extra features.

Text watermarking input screen

Watermarker app ready!

February 3rd, 2012

Watermarker app icon2 days ago our latest App Store iteration saw day of light on the App Store. It’s a video watermarker app which makes it pretty easy to imprint your logo or for that matter a small text into your video. When we created this we had journalists, bloggers in mind who create and deliver video content to a website or third party and are always using more or less the same watermark. Now its possible to create a fully montaged production in the field just using your phone. Shoot with our other app CamLock, brand the video with a text or image of choice (mail a transparent png to yourself save it to the photoroll and select it in the app) with the Watermarker app and you could use an app like iMovie to do some basic video montage. So there you go, just in time video delivery is finally there!

Tutorial video:

Bullet Time (The End of The World Party) in Dutch App Store

October 5th, 2011

Screen shot 2011-10-05 at 8.48.05 AM

So the day after laucnh we’re at position 33 in Category Adventure in Dutch App Store (for iPhone rankings ), we’re now beyond the legendary “Another World” and hope to climb up a few places still. So that’s it basically, the game has entered the App Store  at the same date as we set the availability date. This hepled us a little I think because we were nicely in view when sorted on release date, this was the case on every platform. So on the iPad we were in the last 12 released apps (no specific category!) and also in iTunes in recently released iPhone /iPad adventure and action games. Also in the GameCenter section, which I never visited before (oops). So hope sales will go strong for a couple of days, we’ll see.

Oh yeah just in case you want to buy Bullet Time too, here is the link to the App Store:

Bullet Time got approved!

September 28th, 2011


4 October, put it on your agenda people! Not only will Apple probably anounce their latest iteration of the iPhone at this beautiful day. But we at will launch our spectaculair iPad-iPhone game: “Bullet Time (The End of The World Party) ”

After a small misunderstanding about our GameCenter implementation, we appealed for a re-evaluation of the game and with success, we quickly got approved to the App Store. The release date is set at 4 October and we hope you will have a good time playing it.

BulletTime submitted (finally)

September 15th, 2011
Waiting for review

Waiting for review

Yep, right now BulletTime is at Apple’s mercy, whether or not it will be approved for the App Store.

Right now we are waiting with high anticipation..

In the meantime we created a Gamecontrol demo, to show off the controls for BulletTime, we don’t use virtual joypads, instead movement is controlled using the accelerometer and only 2 buttons for jumping and shooting. Not tiny onscreen buttons, left half of the screen is jumping, right half is shooting, (Of course you can toggle that if you like that better).

Bullet Time Pre Release trailer

September 6th, 2011

Today we shot our trailer, we decided to use pure “in-game” footage for this trailer so people realy get to see what to expect from this game. In order to shoot this video we hooked our iPad up to an HDMI monitor and filmed that monitor with an iPhone using our own Camlock app. We decided to stick to 4:3 aspect footage because of the aspect ratio of an iPad which matches that ratio. The footage is not as clear as screengrabbed from the iPad simulator on a Mac, but because our game controls rely on the accelerometer and multitouch (shooting and jumping at the same time) playing on the simulator doesn’t work out.

So here it is: has been facelifted

August 30th, 2011

In order to accomodate the huge amount of traffic, because of our soon to be released iPad/ iPhone app title Bullet Time (The End of the World party),  to the support site, we have overhauled our website. It’s basically a sister site of which is more focussed on iOS development on private label instead of our work for third parties. So to say “Our own Stuff”. So check it out website website