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
sounds.
It may sound hard but most of it is pretty mundane. Scraping the NIST database is just a program visiting pages for wavelength ranges 0-100, 100-200 etc. to get all the data. Then it parses the HTML tables into a hash table indexed by element name ("H", "O", "C", "Na") which gives for each element an array of pairs of floating point numbers (wavelength of spectral line, strength of spectral line).
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.
