Document Type

Undergraduate Project

Date of Degree Completion

Spring 2018

Degree Name

Bachelor of Science

Department

Mechanical Engineering Technology

Committee Chair

Dr. Craig Johnson

Second Committee Member

Professor Roger Beardsley

Third Committee Member

Professor Charles Pringle

Abstract

High altitude balloons are large latex balloons filled with gas that carry payloads to near space. They provide a convenient way to study the Earth’s atmosphere. Per Boyle’s Law, the pressure and volume of a confined gas are inversely proportional. Thus, as the balloon ascends and the atmospheric pressure decreases, the gas inside the balloon expands. This pressure difference allows the balloon to ascend, but it also causes it to continuously expand until it bursts. For some observations, one might want their balloon to remain at constant altitude for a period of time. One way to achieve this is to periodically decrease the volume of the balloon by releasing some of the gas. The objective of this project was to design a valve with a sensor to periodically release gas during flight. The valve was designed in SolidWorks and was 3D printed. A push-pull solenoid was mounted to the inside of the valve and wired to a microprocessor, along with an altimeter sensor to measure altitude. The microprocessor code was written based on altitude and the known pressure gradient versus altitude on Earth. The pressure valve has proven to be fully autonomous. However, testing determined that the valve could not successfully hold helium with leakage of less than one percent per hour. Therefore, the valve could not be tested in actual flight.

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