Smartphone Spectrometer

Making a Spectrometer from a Smartphone Camera

If one puts a diffraction grating in front of the lens of a smartphone the photograph will show the spectrum of a light source. This works best in a dark environment where the spectral lines show up on top of a dark background.  The following picture was taken from about 1 m away from a hydrogen lamp. The  spectral lines of the Balmer series are clearly visible. One can also see the spectrum of the neon pilot lamp below and to the right of the hydrogen lines. (Photo taken in SFU Phys131 lab, March 10, 2015)

Hydrogen Balmer Series

Hydrogen Spectrum made with a smartphone and diffraction grating. Note the little neon spectrum too.
Hydrogen Spectrum made with a smartphone and diffraction grating. Note the little neon spectrum too.
Hydrogen Balmer Spectrum
Colour Actual λ(nm); Measured λ(nm) ni nf
red 656.3 654.4 3 2
bluegreen 486.1 487.7 4 2
violet 434.1 435.7 5 2
violet 410 6 2

The wavelengths were derived my photo-analysis using LoggerPro and calibrated on the red Balmer line.  I assumed a linear relationship between wavelength and distance from the lamp. The second order bluegreen line is visible and its wavelength would be 997/2 nm  = 498.5 nm using the linear relationship between wavelength and distance.

 

See http://spectralworkbench.org and this  for a home made spectrometer using a DVD diffraction grating.