MEC202

Project Background and Objectives

Background: With the development of technology, there is an increasing demand for intelligent household facilities. However, traditional outdoor clothes drying racks can damage clothes in bad weather, and most smart drying racks on the market are designed for indoor use and take up a lot of space.

Objectives: To design a smart clothes drying rack that can be used outdoors and automatically retract and extend in specific environmental conditions, meeting users’ needs for saving indoor space, automatically responding to weather changes, and switching between manual and automatic modes.

Design Concepts and Screening

Application Scenarios: It can automatically collect clothes on rainy days, windy days, and in wet weather, and automatically extend on sunny days. It can also stop when the user presses the pause button and prevent overextension through limit switches.

Comparison of Design Concepts

Full Automation: It can automatically adapt to the weather without user intervention, which is convenient but has high cost and high complexity.

Partial Automation: Users can control it, but manual intervention is required. It has low cost and a simple system but there is a risk of clothes damage.

Design Concept Selection: Considering comprehensively, a design that can automatically retract and extend according to environmental changes is selected. The arm mechanism is used as the main structure, and a 220V AC stepper motor is used for driving and controlled by relays, which has high compatibility and maintainability.

Prototyping and Testing

Physical Prototype and System Functionality: The size parameters of the physical prototype are introduced, and the system workflow is described, including initialization, environmental detection (light, wind, rain, humidity) and corresponding actions. The circuit connection is also explained.

Sensor Integration: An IO expansion board is used to integrate sensors such as wind speed, light, humidity, rain, limit switches, and stop buttons to ensure stable and reliable connections. The connection ports of each sensor are also introduced.

Physical and Control System: The motion mechanism of the swing arm is realized by a stepper motor and relays. The model, parameters of the motor and the function of the relays are introduced, as well as the power supply situation.

Testing

Test Method and Results: Different weather conditions and operations of buttons and limit switches are simulated for testing, and the results are all normal. The details are recorded in the video.

User Feedback: The System Usability Scale (SUS) is used to collect user feedback. 80% of users think the product is qualified and easy to use, and half of the users think it is excellent and have the intention to continue using it. Most users recognize the usefulness of the product.

Project Summary

Discussion: The prototype meets the expectations. The combination of sensors can effectively detect the weather. The collision sensor and the manual/automatic switch button increase the practicability of the product and have commercial value, but further development and testing are needed.

Reflection: There are problems such as limited rotation movement mode, insufficient test samples of the weather judgment program, and vulnerable collision sensors.

Future Improvement: Strengthen the durability of the collision sensor and conduct more extensive tests on the weather detection algorithm.

Contribution: Lists the specific contributions of team members in the project, such as code writing, hardware assembly, and report writing.