Enhancing and validating a low-cost photogate

Abstract This paper presents the development and validation of a low cost instrument that can be used for time interval measurements, and in other physics experiments. It is proposed to build a photogate combining the simplicity and economy, making it simpler and cheaper than those on the market. The construction of this instrument is based on the use of a light-dependent resistor (LDR) and a LASER pointer, with simple and elementary connections, which characterizes it as a low-cost measuring instrument. Its validation was carried out by comparing the results of the moment of inertia of a homogeneous and thin bar and the experiments carried out in a laboratory, proving its effectiveness as a time variation collection instrument. It is also proposed an experimental activity, whose objective is to determine the landing point of a sphere thrown horizontally from the top of a table at any speed. Its use tends to facilitate the diffusion and access to this type of instrument of measures between high school teachers and educational institutions, being ideal to constitute a science laboratory.