HCube, Sonar+D and Barcelona

4 min readAug 10, 2015

I just came back from Barcelona and I thought it was a good moment to sum everything up a bit and explain what I’ve been up to there. The main reason I went there was to attend Sonar+D, a well-known exposition managed by Sonar which took place in Fira Montjuic.

My University (UPV) had the opportunity to show some project there and it reached directly to a group of active students where I belong to called ‘Makers UPV’. We mainly develop projects and courses for other students during the year, and they had good references about us. We had to think of a cool idea to show there and we came out with what we called ‘HCube’: a tridimensional LED screen and in a cube-like structure.

It was nothing new to us, as we had prepared courses to build LED cubes before. However, we made that idea 300 times bigger. (HugeCube)

We spent almost two months to complete and fully assemble every LED (8,000) to the electronic mechanisms and the physical structure while developing a consistent and comprehensive software ready to control and manage the great amount of LEDs which had to do something visually definite and interactive for visitors.

Software development

Building and connecting every wire was a real challenge, but we knew how to solve it. However, developing a custom software which could control, manage and create visual effects for HCube was something making the whole team losing sleep. I was in charge of that field, and it took me weeks to decide what was the best and most reasonable way of getting it done.

Then, I realized our project was very similar to a 3D videogame. It was a 3D cube where animations and effects could be displayed, just as if it was a 3D stage where games run and users interact and play with. I downloaded Unity 5 with some sample code, as I had never worked with games before, and learned how game objects worked with scripts. At that very moment, I knew something great could be accomplished with that tool: pointing 6 different cameras at every side of a bounded scene and analyzing what happened moving them in depth, was enough to create color matrixes ready to be sent to hardware to turn on LEDs and create 3D scenes in the HCube.

That first approach was key to develop the final software we used to control the system, and although we had several problems with performance at first, we managed to solve them using some cool techniques provided by Unity called “Render Textures”, saving up GPU and CPU computing time and getting almost 90 FPS streaming right to two Teensy activating half of the cube each, accomplishing real time animations and user response.

Moreover, Unity 5 was a great framework which made easy to implement third-party animations, games and peripherals which in other circumstances would have been impossible to manage.

Applications

We wanted to take advantage of the great backend HCube was using, so during Sonar+D, we developed applications for it. We started analyzing the audio input to create a 3D equalizer to display inside the cube. We also connected it to twitter, so that visitors could send tweets with a given hashtag and they would appear instantly in the very first layer of the cube. Leapmotion was also included with two great demos where users could move a ball with their hands and watch it perform live in real 3D.

Moreover, I included an open API, so with a simple POST request to the computer managing HCube developers could send a matrix of colors ready to be displayed.