Code here
Executable here

Conclusions

 Stay away from your power supplies...especially if you are a Mac owner!
Your laptop draws more power [expectedly] when you are computing heavily and charging the battery. In fact when the CPU is chugging, the readings were often well over 199 gauss! Worse than CRT monitors.
Using glyphs with scaling on produces very informative graphs with 4D data.
Keeping it simple in visualization is good.
***** Data collection is a major pain in the behind!!!!!!
Here is a tiny list of complaints
      Tedious
      Time consuming
      Frustrating
      Not always rewarding

VTK [yes again]

I used C# with the .NET dll's yet again...for the obvious reasons...because I learned how to use it from the last two projects and I found that it work well with my object-oriented thought process.

EM Data Collection

 No Picnic
I picked EM because I thought it would be interesting...and actually it is quite interesting the amount of radiation that is out there, but at the same time getting the data was no picnic.

Of all the electronics, why a Mac power supply why now?
Dat and I originally started getting data from an old 21inch CRT monitor...with high readings of only 60 and in a very small area around the top and the back. We didn't feel like we were getting our work's worth of data, so we started exploring other things. Here is a list of the other things with what we found...
  • Speakers [car and home]: had to turned up pretty high before any real data and even then well under 30 at high volumes.
  • CRT 21': highs at around 50-60 and really large drop offs compared to the size, about 2 inches above the back gave readings under 5.
  • TV 27': basically the same as the old CRT monitor.
  • Laptops: Not too much data anywhere, some on the keyboard, but barely any.
  • Cellphones: Not much in the way of EM, even during calls, maybe the spikes are too quick?
  • LCD: surprisingly there was large readings right around the back...where the power came in, but that's about it.
  • Tablets: much like the laptops. Desktops: again a lot around the power supply but not much else where.
There was obviously a pattern occuring here, and one would think Dat and I picked up on this and that's why we picked the Mac power supply...one would be wrong. Dat actually stumbled upon it when he was using his laptop waiting for a ride and had the EM reader on next to his power supply...with striking readings of 80! He called me and told me so I tried it on my Mac power supply and wouldn't you know it I was getting readings off the charts.

Data collections...its the pits
See comments above in conclusion section.

Visualization

 As mentioned above, keeping it simple here really helps let the data talk. When we were collecting the data I didn't see any patterns, in fact I saw what looked like a weird X pattern, but in the visualization you can clearly see that what I thought I was seeing was actually an '8' shape, as expected in EM's...I think. I would have really liked if the data could give some sort of direction, maybe it does, and I just didn't know how to get it.

Either way, I am pretty pleased with the visualization, the user can clearly see the fields, I would have liked to get more data, but I don't think it would have been that much more useful. The best would have been if we had a more refined EM reader that could be placed in tigher spots, I would have liked to get a finer grain reading and have lots more time...but can't have it all :(.

Features of the visualization...
  • Elegantly simple
  • 4 ways to visualize the data
    • Directional Box separated
    • Magnitude Box composite
    • Magnitude Spheres
    • Arrows
  • Enough customization without useless customization
  • Clipping
  • Easy snap shooting
  • Clean GUI
Snap Shots

Separate cubes with same color and scaled glyphs.
Separate cubes with different colors.
 

Scaled glyphs, scaled on vertical data.
Scaled glyphs, scaled on horizontal data with horizontal cubes.
 

Unscaled glyphs.
Scaled composite only.
 

Side view of the scaled composite view only showing 1 inch above data.
Top view of cube composite.
 

Spheres, actually confuses the data due to occlusion.
Arrows, doesn't give too much more information.
 

Me collecting data.
Dat collecting data.
 

Our grid.
Monitor data collection.
 

Dat collecting monitor data.
What math thinks EMF should look like...
Happy SUMMER!