Resonance Cell for Measuring the Speed of Sound in Gaseous Substances

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https://projecthub.arduino.cc/aewolframio/7035c37c-b045-47c1-a7c5-fd7dc502cacb The speed of sound in an ideal gas is related to two characteristics of the gaseous substance, its molecular mass in kg/mol and its adiabatic constant ( heat capacity ratio ), or its average values in case of being a mixture of gases. It is for this reason that the measurement of the speed of sound can be used as a preliminary way to identify a pure gas or mixture of gaseous substances. The measurement can be performed using an ultrasonic proximity sensor, to measure the round trip time ( t/2 ) of a sonic pulse in a tube of known length ( x ) (echo method), filled with the gas under study ( v = 2x/t ). Since the speed of sound is also absolute temperature ( K ) dependent, it must be measured using a temperature sensor. The values measured by the sensors are captured and processed by an Arduino microcontroller that transmits them via bluetooth to a mobile application, designed with MIT App Inventor 2 , which will allow to calibrate the length of the tube using a reference gas whose sound speed is known. The application will use this information to calculate the sound speed of an unknown sample of gas and perform preliminary identification.