Design and application of a low-cost camera-based spectrometer

Spectrometers are instruments that are used to measure different optical properties such as transmittance, absorbance, and concentration of liquid and solid samples. The standard spectrometers are big, bulky, nonportable, and costly. This makes them inaccessible to integrate into portable devices. We have developed a handheld low-cost camera-based spectrometer. It consists of a camera, direct vision spectroscope, and Raspberry Pi board. The components are enclosed in a 3D-printed structure. The spectrometer is calibrated using laser light sources. In liquid samples, when the light from the source passes through the sample and the transmitted light passes through the direct vision spectroscope, a spectrum is formed. The spectrum seen in the direct vision spectroscope is captured by the camera and processed using a Raspberry Pi board using a Python program. The results can be displayed in a graphical user interface in the mobile phone or computer connected wirelessly to the Raspberry Pi board. Based on the wavelength range of light source, the absorbance spectrum in the visible region can be measured using the spectrometer. The absorbance of different concentrations of food color samples are measured and compared with the standard spectrometer. The results of the device are comparable with the standard spectrometer.