The HARP project

This project was made by three students of Télécom ParisTech as part of the Embedded Systems course (ELECINF344/ELECINF381 aka ROSE).

At the beginning it was just a joke, we where looking at RoseAce , a project from last year in the same course and one of us said that even if their project was awesome, there was still a dimension missing..
And so it begins ..
But was it possible to create a POV (persistence of Vision) Hologram ? The few examples we found on the Internet were really disappointing: low resolution, not real 3D holograms.
We also found lots of huge cubes made of LED’s which were, let’s admit it, awesome too  (wink Roled Cube). But nobody got time for welding more than 1500 LED’s together .. So we had to find a new solution.

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HARP loves you!

And we found it:
if RoseAce could build a screen using only a line of LED’s and some POV, we might be able with the same principle to make a cylinder 16 LED’s of diameter x 16 LED’s high x 16 “slice”  only with a 16×16 square which rotates around the vertical axis with its revolution divided in 32 positions (there are two positions per slice in order to make a 360° LED).

After two months we started the tests, and it works !

Our system is based on a Gumstix which controls the whole thing. By creating a char driver using a kernel module specifically designed for our project, we are able to control each LED at each position individually for any rotary speed.

The HARP system

The HARP system

Concerning the front end, our user program reads image files where each frame represents a position around the axis. Hence it is rather quick to produce simple (yet impressive) material for HARP with any image editing application.

Our goal was to make it easy for people to create their own hologram by designing a 3D shape. To do so we created two programs which transform a 16x16x16  LED’s cube into a  16x16x32  LED’s cylinder.  Depending on the content of the hologram, one software would be more appropriate than the other. If you want to create a Hologram just go on Q-block for example and create an image with 16 frames corresponding to the 16 views you have with the “show canvas” option. Run the software in order to make it comprehensible by HARP and then you will just have to display it in 4D (3D .. and time)!

Feel free to contact us for any purpose, we’ll be glad to answer you!