Review of sound card photogates

Abstract

Abstract.Photogates are probably the most commonly used electronic instruments to aid experiments in the field of mechanics. Although they are offered by many manufacturers, they can be too expensive to be widely used in all classrooms, in multiple experiments or even at a home experimentation. Today all computers have a sound card -an interface for analogue signals. It is possible to make very simple yet highly accurate photogates for cents, while much more sophisticated solutions are also available at a still very low cost. In our review we show several experimentally tested ways of implementing sound card photogates in detail, and we also provide a full-featured, free, open-source photogate software as a much more efficient experimentation tool than the usually used sound recording programs. Further information is provided in a dedicated page, www.noise.physx.u-szeged.hu/edudev.

Digital phonocardiographic experiments and signal processing in multidisciplinary fields of university education

“…Interfacing sensors to computers, tablets or smart phones are also possible via the analogue and digital inputs of these devices. The only widely available analogue interface of computers is the sound card, therefore, various measurement applications can be found targeting education [1][2][3][4]. Since the sound card is not designed as an instrument, proper usage and application limitations must be considered carefully.…”

Phonocardiography and Photoplethysmography With Simple Arduino Setups to Support Interdisciplinary STEM Education

“…The methods, circuits and code can be applied in different educational experiments as well even with the same hardware. The optical sensor part can be used to monitor movement of an object as it can serve also as a reflective photogate [53]. This can be useful to support mechanical investigations (pendulums, mass on a spring, collisions, etc.).…”

Low-cost photoplethysmograph solutions using the Raspberry Pi

“…In demodulation, the frequency of the modulated signal should be measured. For that, we used a simple algorithm, which counts the full periods in a fixed time interval [11]. It counts the upward level crossings, u in the measurement window and calculates the time interval appertains to the full periods, t, see Fig.…”

“…This AC component is only a few percent of the DC component. An active bandpass filter can be used (1 Hz -30 Hz) to remove the DC voltage and the high frequency noise [10][11].…”