The problem is that one element, say natrium, has many spectral lines of varying strength. You're trying to find a set of elements that best explains the measured spectrum. If you plotted all spectral lines from all elements on a spectrum, it would be completely black because there are so many. In the end it only worked well for fluorescent tubes, but it could tell you what's in them, even things a human would have a very hard time discovering by looking at the spectrum and manually comparing it to the NIST database (the university has all kinds of weird lamps like natrium lamps, blacklights, and fluorescent tubes in many colors all containing different stuff, and looking at computer monitor pixels is fun too).
My program output an element X who's name I forgot for many of the lamps, but when I plotted its spectral lines over the spectra I couldn't see the match clearly, so I added a parameter to the algorithm so that it would be more restrictive on the number of different elements returned. In the presentations of the lab the prof commented "many of these tubes also contain element X, but you can't see it with the spectrum analyzer you used, you need a higher quality one". Bummer.
You (jules) are discussing a spectrometer, that shows the strength of optical spectral lines to identify materials (http://en.wikipedia.org/wiki/Spectrometer). These are two totally different things - radio-frequency vs optical. (Just want to keep the discussion from getting totally confused.) Also, Natrium == Sodium (Na)
In my first year in a lab I built a program
that scrapes the NIST spectral database, reads the data
from a spectrum analyzer attached to the computer, and
figures out which types of atoms the thing the spectrum
analyzer is looking at contains. This is harder than it
Talking to the spectrometer is boring too: you have your program execute some other program that comes with the spectrometer, which talks to the spectrometer and saves a file containing a list of floating point numbers which describes a graph like this (http://upload.wikimedia.org/wikipedia/en/thumb/5/5d/Spectra-...) with data points. The floating point numbers come in a weird format that the standard floating point parsing function can't handle, so you munge it a bit with a regex.
Of course not forgetting the GPL drivers for the same: http://im-megpldrivers.sourceforge.net/
Also, $16? I paid £0.99 for mine on ebay :)
Do hackers of this device risk running afoul of laws against intercepting mobile phone transmissions?
Also there is no realistic practical way to passively detect a passive detector. Plus how would they distinguish you from someone on a normal mobile phone?
Is that true? I heard that the BBC license police used "receiver detectors" to find unlicensed TVs.
Just think of it as part of our eccentric british ways.
EDIT: just to add, I pay my license fee, happily, even though I dont have to because its not required to watch the iPlayer streaming service, which is how I watch almost all my TV. The fee is pretty cheap considering the sheer breadth of services the BBC provides. The UK would essentially fall apart without it culturally.
Edit: More broadly, you could say that just from the deterrent effect of their PR, they "work".
Very cool mod, though.
I found mine for $15.99 and free shipping on eBay.
But this is a frequency analyzer for finding overtones to determine broadcast frequency at close distance.
EDIT: I didn't see that the keys were alphanumeric and thought that was its intended purpose. I thought maybe they were going for the "science girl" demographic, which would have been cool.