Low-cost spectrograph based on a WebCam: a student project

Abstract

This work describes the implementation of a low-cost spectrometer produced with common objects and proposed as a pedagogical students' project. This task aims to introduce the theme of image detection and to stimulate the students to develop skills in the field of optics and photonics. The performance of the developed spectrometer was tested in the characterisation of several sources such as light emitting diodes (LEDs) operating in the visible spectral range and the results were compared with those obtained with a commercial spectrometer. Foreseeing a possible application, the spectrometer was used to calculate the emission (x,y) colour coordinates following the Commission Internationale d'Eclairage (CIE) definition of the LEDs. The calculated (x, y) colour coordinates using the built spectrometer compare well with those calculated using the emission data measured using a commercial spectrometer, pointing out that the proposed methodology provides good resolution and precision in the calculation of the CIE colour coordinates. This project was offered with success in 2010 to students from the Optoelectronics unit of the Physics Engineering Masters degree at Aveiro University, Portugal.