Testing Considerations

1. SOAP: SCUBA Oxygen Analysis Project May07-17: Oxygen Analysis System for SCUBA Equipment Faculty Advisor Client Team Members Dan Stieler dstieler@iastate.edu Adam Petty, EE apetty@iastate.edu Michael Beckman, EE beckmanm@iastate.edu Rory Lonergan, EE wowy@iastate.edu Jeff Schmidt, CprE jefferys@iastate.edu Project Web Site http://seniord.ee.iastate.edu/may0717/ Introduction Project Requirements Abstract The team’s goal is to create an oxygen analyzer to determine the oxygen content of SCUBA tanks. In this project’s case, the objective is to remove human error from SCUBA diving and provide additional features to the diver. To remove human error, the oxygen analyzer will not only be able to measure the percentage of oxygen in the tank, but it will also be able to determine the maximum operable depth without the need for complex dive tables. This will not only make it easier for divers to determine maximum depth, but it could also save lives by removing one source of human error. Acknowledgement The team would like to thank their client, Dan Stieler, for proposing this project. He has provided a lot of insight into oxygen sensors and analyzers and has given the team some great ideas about how they could design this system. The team would also like to thank Dr. Tuttle for his insight on the design, and the SSOL for use of their equipment Design Objectives • The device shall take an input from an oxygen sensor. This shall be a DC signal that will correspond to a respective fractional percentage of oxygen in the tank. • The LCD screen will be used to convey the device’s output to the user. It should be able to display the percentage of oxygen in the oxygen tank and the maximum operating depth. Functional Requirements • Calibration: The device will be calibrated via a round knob found externally on the device’s case. • LCD screen: The LCD screen will be used to convey the device’s output to the user. • Oxygen sensor: The sensor must be capable of connecting to and reading in oxygen content of a SCUBA tank. • Power switch: The device should have a labeled switch that powers up and powers down the device. Design Constraints • Oxygen Sensor: The sensor that will be used for the project will be the Teledyne R22D. • Power: The final product will be powered by a 9V battery. • Size: The device will be scaled to fit into an 8 inch by 4 inch by 2 inch enclosure and shall not weigh more than 5 pounds. Measurable Milestones • Project Definition • Research and Technology Selection • Product Design • Product Testing • Product Documentation • Product Demonstration Problem Statement Current commercial oxygen analyzers for SCUBA diving are expensive and contain minimal features to aide divers when they are analyzing the oxygen content of their tanks. This can dissuade people from taking up SCUBA diving as a hobby, so the team’s client proposed that a hand held device be built with an LCD display that will accurately analyze the contents of a SCUBA tank. This device should be able to display the percentage of oxygen, and the maximum operating depth for an oxygen enriched mixture. It should also be reasonably inexpensive to create and very reliable. Operating Environment This device will need to operate in many environments. Since it will be used to analyze tanks both indoors and outdoors, it should be water resistant and relatively immune to temperature changes. However, this device is not expected to be water proof, nor is it expected to operate in temperatures above 120 degrees F or below 32 degrees F. Also, though it will be designed to be durable, it is not expected to survive extreme physical trauma. Approach and Considerations Technology Considerations • Functional Requirements Determined • Consideration of Constraints • Considerations for Technical Approach • Testing Requirements Considerations • Safety and Security Considerations Technology Considerations • Power • Microcontroller Type • Sensor Type and Sensitivity • Input and Output Interfaces • Users • SCUBA Divers • Persons who refill SCUBA tanks • Uses • Analyze the percentage of oxygen • Determine maximum operating depth • Assumptions • Components are commercially available • The team will have access to SCUBA tanks for testing • The device will be cable of being powered by a 9V battery • The complexity of this device is within the scope of the knowledge and time that is at the disposal of the team • Limitations • The device should be mobile • The device should not weigh more than 5 pounds • The device must display the oxygen percentage and the maximum operating depth on the LCD • Testing Considerations • Because of potential life threatening consequences resulting from device malfunction, it is critical that the device be fully tested. The prototype shall not only be tested for functional accuracy, but also for corner conditions such as low battery or weak input signal. The sensor used for the prototype is also tested thoroughly so that its capabilities are fully understood and not exceeded. The results from the testing are important for establishing limits to the operation of the prototype. Since the safety of the user is of primary concern, this step will not be overlooked. End Product Deliverables Resources and Requirements Project Schedule Gant Chart Functional and Tested Prototype A small enclosed fully tested device that can be easily carried by the diver. This device should be able to display the percentage of oxygen, and the maximum operating depth for an oxygen enriched mixture. Documentation The design report is a comprehensive companion to the final prototype. Within the design report is information relating to the operation and detailed design of the device. This report also provides information regarding the technical considerations, different approaches used throughout the course of the design of the device and testing considerations. Personnel Efforts Financial Requirements Closing Summary This project exists primarily to make life easier and safer for SCUBA divers. The team believes this is a noble goal - one that is driving force behind the momentum and ambition to complete a prototype that is capable of meeting the design requirements. The team is confident that it can complete the oxygen analyzer in the given amount of time with the resources available. The flow of design through several steps of design simulation, prototyping, and testing allows the project design to be both manageable and logical, and as such, the delegation of work is being done in such a manner that all team members will feel challenged, but not alone in their efforts. As a result, the entire team feels that finishing this project will be an excellent challenge and is definitely within the members’ capabilities. May07-17 Team Information Gary Tuttle gtuttle@iastate.edu