Abstract
The goal of this mission is to test the speed of sound at different altitudes and ultimately at a maximum height of 100,000 feet (30 km). In conjunction with this testing, environmental parameters including temperature, pressure, and humidity are measured and used to calculate the speed of sound to compare to the measured results. The team constructed the payload “Dorothy” using polystyrene foam due to its lightweight and thermal isolation property. An ultrasonic sensor with a reflection mirror were installed outside payload box to measure speed of sound. All the sensors were calibrated. Software for the project was developed in Arduino DUE. An SD card shield was connected to the Arduino board for data storage and RTC clock. Dorothy was launched at the NASA CSBF in May 2017. However, the ultrasonic sensor stopped working below ‒40 °C and the collected data were noisy. A few modifications were made over the summer of 2017. A heater was attached to the ultrasonic sensor but isolated from the environment. Ultrasonic pings were sent and received more frequently to reduce noise. The polystyrene box was also redesigned. “Dorothy 2” was launched at Southern Illinois University (SIU) during the solar eclipse on Aug. 21, 2017. Test data are analyzed and further improvements are planned.
Keywords: speed of sound, ultrasonic sensor, atmospheric acoustics, ballooning
Included in
Acoustics, Dynamics, and Controls Commons, Digital Circuits Commons, Electrical and Electronics Commons, Engineering Physics Commons
Measurement of Speed of Sound Profile using LaACES Balloon
The goal of this mission is to test the speed of sound at different altitudes and ultimately at a maximum height of 100,000 feet (30 km). In conjunction with this testing, environmental parameters including temperature, pressure, and humidity are measured and used to calculate the speed of sound to compare to the measured results. The team constructed the payload “Dorothy” using polystyrene foam due to its lightweight and thermal isolation property. An ultrasonic sensor with a reflection mirror were installed outside payload box to measure speed of sound. All the sensors were calibrated. Software for the project was developed in Arduino DUE. An SD card shield was connected to the Arduino board for data storage and RTC clock. Dorothy was launched at the NASA CSBF in May 2017. However, the ultrasonic sensor stopped working below ‒40 °C and the collected data were noisy. A few modifications were made over the summer of 2017. A heater was attached to the ultrasonic sensor but isolated from the environment. Ultrasonic pings were sent and received more frequently to reduce noise. The polystyrene box was also redesigned. “Dorothy 2” was launched at Southern Illinois University (SIU) during the solar eclipse on Aug. 21, 2017. Test data are analyzed and further improvements are planned.
Keywords: speed of sound, ultrasonic sensor, atmospheric acoustics, ballooning