MEC202

Project Background and Objectives

Background: After the pandemic, people’s cardiopulmonary function has been impaired and the danger of underwater sports has increased. However, there is a lack of fully automatic diving rescue equipment on the market. The existing mainstream rescue method is manual diving, which has many disadvantages.

Investigation and Requirements: Through investigations such as global diving reports, it was found that the sudden death rate during exercise has increased and emergencies in water sports are frequent, with drowning being the main cause of death. The target customers are diving enthusiasts in complex waters. The product needs to be lightweight, waterproof, and capable of monitoring vital signs and automatically triggering rescue, including functions such as deploying airbags, communication, and positioning.

Project Planning and Division of Labor: The project is divided into three modules: vital signs monitoring, communication and GPS implementation, and mechanical automatic airbag design, which are carried out simultaneously and finally integrated. Team members have clear division of labor. For example, Yingzhuo. Pan is responsible for the communication and GPS modules and system integration, while Weiqin. Xu is responsible for the blood oxygen monitoring module and report production.

Design Concepts

Requirements and Functions: In response to the challenges of cardiopulmonary function of underwater sports participants and the need for emergency rescue, the focus is on diving rescue. A wearable rescue device is designed with vital signs such as blood oxygen, heart rate, and body temperature as triggering conditions.

Concept Selection and Prototype Design: Integrate existing functions on the market with the Arduino processor as the core to build a system. After analyzing the advantages and disadvantages of products such as inflatable rescue bracelets and GPS modules, a prototype including a monitoring system and a rescue system is designed. The monitoring system includes blood oxygen and temperature measurement and GPS positioning modules, and the rescue system includes communication and mechanical automatic inflation parts.

Prototyping and Testing

Challenges and Solutions

Blood Oxygen and Temperature Monitoring: The first blood oxygen monitoring module was unstable. By referring to an open-source project on CSDN, the values were stabilized and the temperature sensor LM35 was introduced.

Communication and GPS Modules: The SIM800C module achieved communication but was unstable when integrating GPS. The problem was solved by switching to the SIM868 module and replacing it with the Arduino MEGA development board.

Steering Gear and Airbag Trigger: It was envisioned to use the steering gear to trigger the airbag of the life-saving bracelet. After many attempts, due to time constraints, it was not perfectly achieved, but the number of rotations of the steering gear was limited through programming.

System Connection: The circuit of the system was successfully built to achieve all functions, but there were failures and conflicts in the ports.

Testing Problems and Solutions

Stability of Blood Oxygen Values: Measures such as taking the average value, changing the sampling frequency, and trigger threshold conditions were taken to solve the problem of unstable blood oxygen values.

Stability of the Communication Module: The instability of the communication module was caused by power supply problems. It was solved by using two 3.4V lithium batteries and a DC power port for power supply.

Trigger Structure Problems: Many methods were tried to solve the problems of the steering gear rotation and connection. Finally, the specific number of rotations was controlled through programming.

Product Design Problems: The preliminary packaging and appearance design of the product were completed by drilling holes to lead out wires, grinding the internal structure, fixing the circuit with hot melt adhesive, and using copper tube tools for parallel connection.

Project Summary

Overall Conclusion: The basic function design was completed, including vital signs monitoring to trigger rescue, automatic communication, and GPS tracking. However, there are still some deficiencies due to time limitations.

Social Impact: It is expected to improve the safety and participation of underwater sports and reduce drowning accidents.

Improvement Suggestions: The product has problems such as insufficient waterproofing and unreliable steering gear valve opening. In the future, a more advanced 3D printing structure needs to be used for improvement to enhance waterproofing and the success rate of valve opening.to improve the technology.