  Accurate calibration of polarization dependent optical elements is often
necessary in optical experiments. A versatile polarimeter device to measure the
polarization state of light is a valuable tool in these experiments. Here we
report a rotating waveplate-based polarimeter capable of complete Stokes vector
analysis of collimated light. Calibration of the device allows accurate
measurements over a range of wavelengths, with a bandwidth of >30 nm in this
implementation. A photo-interrupter trigger system supplies the phase
information necessary for full determination of the Stokes vector. An Arduino
microcontroller performs rapid analysis and displays the results on a liquid
crystal display. The polarimeter is compact and can be placed anywhere on an
optical table on a single standard post. The components to construct the device
are only a fraction of the cost of commercially available devices while the
accuracy and precision of the measurements are of the same order of magnitude.
