Ah, yes. Stereoscopic vision.

This is a follow-up to my previous article, in which we explored the choice of PCB placement in order to get an optimal visibility.

My previous analysis only covered the case of a punctual point of view. However, most people have two eyes, which provide a double point of view and could increase our coverage of space. It is to be pointed out that a point of space seen by one eye does not provide depth information to the brain, however let us assume that our image perception is smart enough to overcome this limit.

In the following simulation, we used a typical eye distance of 6 cm.… Read more

Choosing a shape

As stated in this previous post, we have to compare different PCB dispositions to avoid blind spots. We soon came to realization that we would not be able to get rid of blind spots with our design, but it is possible to study the different ideas we came up with in order to mitigate this issue.

That’s why we created a python program that can simulate :

  • blind spots created by PCBs hiding each other
  • the variations of brightness due to the fact that LEDs can be seen at an angle (which is what created the dark center zone in CyL3D, which we are trying to get rid of)

Stairs : an iteration over CyL3D’s design

To avoid the issue of a dark zone due to all LEDs facing the observer at an angle in the center zone, an idea was to make sure that all LEDs were not facing the same direction.… Read more

Power and data transmission

One of the issues that LitSpin raises is power transmission between moving and static parts. One idea that came to mind was induction but we didn’t know whether integrated solutions existed and if they did, would they work with our power requirements.
Würth Elektronik offers a plug and play development kit that allows for 200W of output power which solves our power transmission issues.

Since the coils work using resonent induction, W.E. integrated frequency modulation in order to allow I²C data transmission. This could allows us to put the wifi module on a static PCB and get rid of the signal drops that were present on previous projects with spinning wifi modules.… Read more

Design Crisis

We discovered our first model contained a lot of issues. The outermost PCB often hide PCB behind them as you can see below. This results in some voxels being invisible. So we decided to create a simulator on Python to find the invisible areas. We will use it to determine the optimal configuration for our display. This configuration has several parameters such as the number of PCB, their position and the arrangement of the LED on one or both sides.

This a an example with 8 double-sided PCB in double spiral and 100 angular resolution. The blue dots are the visible voxels.… Read more

Meet LitSpin

Our goal is to build a 3D POV (Persistance Of Vision) display with no black zone in the middle.

Last week we mainly discussed the technical limits of our project. See here for more information.

Thinking about it, we discovered a number of challenges that we will have to face:

  • Our project will have a spinning part and a base, and we will have to find a way to transfer power and information between both parts:

Concerning the power transfer, we thought of induction, but the main constraint is the available power. We will need between 50 and 100W of power for the PCB, and there are not many induction transmitters that can transmit that much power.… Read more