Electronics Design and Enclosure Design

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Introducing electronics design to Year 11 NCEA students in New Zealand, especially if it's their first time engaging with the subject, provides a valuable and exciting opportunity to explore practical applications of theoretical knowledge. Given their introductory level, the focus should be on foundational concepts and hands-on experiences that build confidence and interest.

Simplified, real-world projects can help students grasp the basics of circuit design, component functionality, and prototyping, while also encouraging creativity and problem-solving. Emphasising a system design approach, where clear inputs and outputs are defined, along with thoughtful housing design, will make the learning process more tangible and relatable.

By fostering a supportive environment that allows for trial and error, iterative improvements, and collaborative learning, students can develop a strong foundation in electronics that prepares them for more advanced studies in the future.

Electronics form the backbone of countless devices we use every day, from the smartphones in our pockets to the computers in our schools.

However, designing these electronic systems goes beyond just creating circuits; it involves careful consideration of how the components work together, the user interface and how they are housed within protective enclosures.

In this unit, we will explore both the fundamentals of electronics design and the essential role of enclosure design.

Design an Electronics Outcome (AS92007)

This design assessment for your Year 11 NCEA Electronics course will help you apply the skills and knowledge you have gained to create a functional and thoughtful electronic project.

You will be guided through the process of identifying a need or opportunity, generating and refining design ideas, and evaluating your final design. The goal is to ensure your project not only meets its intended purpose but also considers the needs of its users and the context in which it will be used. Refer to the information on this page to help you complete your design.

Although many choices in electronics design can be non-digital, the focus of this unit is on creating a digital electronics outcome. This means your project should include a microcontroller and/or leverage digital technologies to achieve its goals.

The Importance of Electronics Design

To design effective electronic systems, you need a solid understanding of how different components function and interact. This includes knowing how to design and assemble circuits, select appropriate components, and ensure that your design meets specific requirements. You'll learn about the roles of various electronic parts, such as resistors, capacitors, and microcontrollers, and how to use them to create functional systems. Additionally, you’ll gain experience with electronic design tools and techniques that help bring your ideas to life.

This was covered in the previous sections.

Why a System and Housing Approach?

While understanding electronic design is crucial, focusing solely on the technical details can be overwhelming, especially at the high school level.

Instead, taking a system and housing approach can simplify the learning process. By focusing on how electronic components and subsystems fit together to achieve a desired outcome, and how to design enclosures that protect and enhance these systems, you can gain a more holistic understanding of both design areas.

Aspects of Electronics Design

In the field of electronics, design encompasses a range of specialised approaches, each aimed at addressing different aspects of creating functional and effective devices. Understanding these various types of design is essential for developing electronic systems that are reliable, manufacturable, and user-friendly.

System Design

System Design takes a holistic approach to creating electronic systems by focusing on how various components and subsystems interact to achieve a specific functionality. This type of design involves defining clear inputs and outputs, specifying how different parts of the system communicate, and ensuring that the overall system meets its intended objectives.

System Design helps ensure that all components work together effectively, providing a cohesive and functional solution. It is particularly important for managing complex projects where multiple elements need to be integrated seamlessly.

Enclosure Design

Enclosure Design involves creating protective housings for electronic components and devices. This design type focuses on ensuring that the enclosure not only protects the electronics from environmental factors like dust and moisture but also integrates user interface elements such as buttons, displays, and connectors.

Enclosure Design balances functionality, safety, and aesthetics, providing a user-friendly experience while safeguarding the internal components. Effective enclosure design also considers factors like heat dissipation and ergonomics to enhance the overall performance and usability of the device.

Design for Test (DFT)

Design for Test focuses on creating electronic systems that are easy to test and diagnose. This approach involves integrating features into the design that facilitate testing and troubleshooting, such as test points, diagnostic interfaces, and built-in self-tests.

The goal of DFT is to ensure that any faults or issues can be identified and corrected efficiently during production and maintenance. Effective DFT helps improve the quality and reliability of the final product by making it easier to detect problems and verify that the system performs as intended.

Design for Manufacture (DFM)

Design for Manufacture is concerned with creating designs that are easy and cost-effective to produce. DFM involves selecting materials and designing components with manufacturing constraints and processes in mind.

Key considerations include simplifying assembly processes, minimizing the number of parts, and choosing materials that are readily available and affordable. By focusing on DFM, designers can reduce production costs, avoid manufacturing complications, and ensure that the product can be scaled from prototypes to mass production smoothly.

By understanding and applying these different types of design, you can create electronic systems that are well-tested, easy to manufacture, functionally cohesive, and user-friendly.

Each design approach plays a crucial role in ensuring that the final product meets both technical and user requirements, leading to successful and effective electronic solutions.

The Design Thinking Process

A structured process or project approach is essential for designing and developing the complexity of electronic design and ensuring successful outcomes. This involves following a systematic workflow, from initial concept and client requirements to design, prototyping, and final testing. Designing for a client means understanding and addressing their specific needs and preferences, which adds an additional layer of complexity but also ensures the final product is relevant and useful.

Iterative improvements are key to refining and enhancing your design. By testing prototypes, gathering feedback, and making incremental adjustments, you can continually improve your design, address issues early, and achieve a more polished and effective final product. This iterative process helps manage risks, adapt to changing requirements, and produce high-quality, client-focused solutions.

By the end of this unit, you will have developed a solid foundation in system design, enclosure design, and the principles of designing for manufacture and test. You will also gain valuable insights into the importance of a structured project approach, designing with client needs in mind, and the iterative process of continuous improvement. This comprehensive approach will help you create functional, manufacturable, and client-focused electronic devices, providing a practical and insightful understanding of the entire design process.

Also see, the Design Process, on the Design for Web page. Also review the concepts of kaitiakitanga and manaakitanga.

The Electronics Design Process

The electronics design process is a structured approach to developing electronic systems and devices from initial concept to final product. It involves multiple stages, each with specific tasks and objectives. Here’s a detailed overview of the electronics design process:

1. Define the Problem

Identify Needs: Understand the problem, need or opportunity that the electronic device aims to address. Engage with various stakeholders and clients.
Define Requirements: Defining requirements means gathering information from stakeholders to understand what they need from a project. This involves talking to users, creating scenarios for how the system will be used, and understanding the project's goals.
Both functional (what the system should do) and non-functional (quality attributes like speed and security) requirements are identified. Clear documentation and validation with stakeholders ensure that the requirements are complete and agreed upon, making sure the project meets everyone's expectations.
Important Considerations Beyond Client Expectations: Consider all important factors in the design, such as compliance standards and aspects like manaakitanga (care and hospitality) and kaitiakitanga (guardianship). These are often overlooked by clients but are crucial for a successful project.
Specifications: Create detailed specifications that cover functionality, performance, power use, size, cost, aesthetics and compliance standards. Specifications explain how designers and developers will meet these needs.

2. Feasibility Study and Research

Initial Research: Investigate existing solutions, technologies, and components.
Feasibility Analysis: Assess the technical and economic feasibility of the proposed design. Identify potential challenges and risks.

3. System Design

Architecture Design: Develop a high-level block diagram outlining the system architecture, including major components and their interactions. This diagram provides a clear overview of how different parts of the system will work together to achieve the desired functionality.
Component Selection: Choose suitable components (microcontrollers, sensors, power supplies, etc.) based on the defined requirements. Consider factors such as compatibility, performance, and cost to ensure that each component meets the system's needs.
Housing Design: Design the physical enclosure that will house the electronic components. This involves selecting materials that provide protection against environmental factors like dust, moisture, and impact, as well as designing for thermal management and user interface integration. The housing design must accommodate all components while ensuring ease of assembly and user accessibility.

4. Schematic Design

Create Schematic: Develop detailed circuit diagrams showing component connections, including low-level design aspects such as resistor values, capacitor ratings, and power supply connections. Ensure all components are accurately placed and connected to meet functional requirements and avoid issues like signal interference or power shortages. Use electronics conventions.
Simulation: Use electronic design automation (EDA) tools to simulate the circuit and validate its performance. Simulation helps identify and correct potential issues by modeling circuit behavior before proceeding to PCB design.

5. PCB Design

Layout Design: Design the printed circuit board (PCB) layout, arranging components and routing traces to meet electrical and mechanical constraints.
Design for Manufacturability (DFM): Ensure the design is optimised for manufacturability, considering factors like component placement and routing complexity.

6. Prototyping

Prototype Assembly: Manufacture prototype PCBs, very board etc and assemble the components. During prototyping, follow established conventions to ensure clarity and functionality.

Use consistent wire color coding to differentiate between power, ground, and signal lines, and follow standard practices for wire routing to avoid confusion and errors. Design interfaces with clear labeling and accessibility to facilitate testing and adjustments
Initial Testing: Perform basic tests to check functionality and identify any immediate issues. Ensure that the prototype reflects the schematic accurately, and be prepared to make modifications based on practical testing and performance feedback.

7. Testing and Validation

Functional Testing: Test your prototype to ensure it performs all the functions you designed it to do. Check each part of your circuit to verify that it meets the requirements and behaves as expected.
Performance Testing: Evaluate how well your prototype manages power consumption and heat. Ensure it operates within acceptable limits and does not overheat or draw excessive power.
Basic Safety Checks: Perform basic safety checks to ensure the prototype is safe to use. Confirm that all connections are secure, and there are no exposed wires or potential hazards.

8. Iterative Refinement

Feedback Loop: Gather feedback from testing, identify issues, and iterate on the design to make necessary improvements.
User Feedback: If applicable, incorporate feedback from potential users to enhance usability and functionality.
Design for Test (DFT):
- Optimise for Testing: Add features to facilitate easy testing and troubleshooting during production. Create test jigs or simple programs to test individual functionality
- Test Points: Incorporate test points and diagnostic features into the design.
Design for Manufacturing: Simplify the design to reduce complexity and make it easier and more cost-effective to produce.

9. Final Design and Documentation

Finalise Design: Make final adjustments and optimisations to the design.
Documentation: Prepare detailed documentation, including schematics, PCB layouts, bill of materials (BOM), assembly instructions, and testing procedures.

By following this structured process, designers can systematically develop electronic products that are functional, reliable, and ready for market deployment. This process ensures that all aspects of the design are thoroughly considered and validated, leading to successful product development and implementation.

Design an Electronics Outcome

In this section, you will find the criteria and guidelines for the assessment of your Year 11 NCEA Electronics project. This assessment will evaluate your ability to identify a need or opportunity, conduct research, generate and refine design ideas, and produce a functional electronic outcome.

The goal is to demonstrate your understanding of the design process and your ability to create a project that meets specific requirements and considers the needs of potential users. Carefully review the information provided to ensure you understand the expectations and standards you need to meet for successful completion of your project.

Step 1: Describing a Need or Opportunity, Potential Users, and Requirements

The first step in your design process is to identify a need or opportunity for your electronic project.

Think about who will use your project and what their requirements are. This involves understanding the potential users and the context in which your project will be used.

Step 2: Research Phase

Once you have identified the need or opportunity, conduct research to gather more information. Look into existing solutions, similar projects, and available technologies. This research will help you make informed decisions and come up with innovative ideas for your project.

You will need a range of design ideas.

Done forget references and acknowledgements.

Electronics Design Document

Step 3: Communicating Your Designs

When you design an electronic project, you need to show how it will look and work once it's finished. You can do this in many ways, such as:

Sketches: Drawing what your project will look like.

Mock-ups and Models: Creating a basic version or model of your project.

Annotations and Descriptions: Writing notes and descriptions about how your project works.

Diagrams and Schematics: Making detailed drawings that show how all the parts are connected and work together.

Design Ideas

Your design ideas can cover different parts of your project. These ideas can be about:

Visual Elements: Things like the colors you use or how everything is arranged.
Functional Elements: How parts of your project interact with each other or with the user.
Technical Elements: Details about the components you use, how they are configured, or the structure of any code you might write.

Step 4: Refining your Ideas

The process of refining ideas involves evaluating these designs, gathering feedback, and making improvements. This ensures that the final design is the most effective and feasible solution.

Design decisions are the choices you make to shape your project. These decisions can be based on:

Feedback: Suggestions and opinions from others.
Research: Information you find about similar projects or technologies.
Design Principles or Usability Principles: Guidelines that help make your project work well and be easy to use.
Conventions and Best Practice: This includes using standard wire color coding (e.g., red for power, black for ground) to ensure clarity and safety, designing intuitive user interfaces, arranging components logically to minimise interference and optimize performance, and clearly labeling all parts of your design with thorough documentation for easier troubleshooting and future improvements.
Rules and Compliance: Consideration of all relevant standards and regulations to ensure your project is safe, reliable, and meets all necessary criteria.
Manaakitanga and Kaitiakitanga: Consideration of these cultural values can mean designing with respect and guardianship in mind. For example, ensuring your project respects the needs and values of the community and environment it serves.

Step 5: Narrow it Down

Evaluate pros and cons of the three choice designs.

Step 6: Research and Evaluate

Summarise research and choice of design.

Step 7: The Final Design

In Digital Technologies, a design demonstrating fitness for purpose is one that addresses the requirements and specifications and considers the potential users and context. This means your project should meet all the set goals and work well for the people who will use it in the environment where it will be used.

By using these methods and considering these aspects, you can create a clear and effective design for your electronic project that meets its intended purpose, respects cultural values, and works well for its users.

Requirement vs Specifications

In electronic design and development, it's essential to distinguish between requirements and specifications. Requirements define what the project aims to achieve from the client's point of view, while specifications provide detailed criteria from the designer's perspective to meet those requirements. Here are some examples.

Portable Thermometer

Requirement (Client's Perspective): Develop a portable digital thermometer that displays temperature readings.

Specifications Designer's Perspective):

Measurement Range: 0°C to 100°C.
Accuracy: ±0.5°C.
Display: 7-segment LED display.
Power Source: 2 AA batteries.

Only specification for portability is a battery bus obviosvly there should be a housing design including.

Smart Thermometer

A bit more complex. You can clearly see how one requirement can equate to a range of specifications.

Requirement: Develop a Smart Temperature Monitoring System for residential use that can measure, display, and transmit temperature data to a mobile application.

By adhering to these specifications below, the Smart Temperature Monitoring System will meet the outlined requirement and provide a functional, reliable, and user-friendly product.

In essence, this is possible for a Y13 student although they may not meet all the specifications and the Level 3 standards. Using the Arduino platform provides many resources that can used to streamline this development.

Specifications to Meet the Requirement:

Core Functionality

Temperature Measurement Range: -40°C to 125°C
Measurement Accuracy: ±0.5°C
Measurement Resolution: 0.1°C
Sampling Rate: 1 sample per second

User Interface

Display: 2.4-inch LCD screen to show current temperature
Control Buttons: Three buttons for power, settings, and calibration
LED Indicators: Red for high temperature alert, blue for normal operation

Connectivity

Wireless Communication: Bluetooth Low Energy (BLE) for data transmission to the mobile app
Mobile Application Compatibility: Android and iOS

Component Specifications

Microcontroller: ARM Cortex-M4, 32-bit
Temperature Sensor: Digital temperature sensor (e.g., DS18B20)
Display Driver: SPI interface for the LCD screen
Bluetooth Module: BLE 4.0 compliant module (e.g., HM-10)

Electrical Requirements

Power Supply: 3.3V DC, powered by a rechargeable Li-ion battery
Battery Capacity: 1000mAh for 24-hour operation
Charging Circuit: Micro-USB port for charging the battery
Protection Circuits: Over-voltage, over-current, and short-circuit protection

Mechanical Requirements

Enclosure Dimensions: 100mm x 50mm x 25mm
Material: ABS plastic for durability and lightweight
Mounting: Wall-mountable with screws or adhesive pads

Firmware/Software Requirements

Programming Language: Embedded C for microcontroller firmware
Mobile App Development: Flutter for cross-platform compatibility
Data Logging: Store temperature readings with timestamps in local memory for up to 7 days

Performance Requirements

Response Time: Update display within 1 second of a new measurement
Reliability: Minimum MTBF of 2 years
Power Consumption: Average power consumption of less than 100mW

Environmental Requirements

Operating Temperature Range: -10°C to 50°C
Humidity Range: 10% to 90% RH, non-condensing
Ingress Protection: IP42 (protection against solid objects larger than 1mm and vertically dripping water)

Usability Requirements

Ease of Use: Intuitive interface with clear labels and indicators
Maintenance: Easy access to battery compartment for replacement
Documentation: Comprehensive user manual and quick start guide

Aesthetic Requirements

Design: Sleek and modern design with a matte finish
Ergonomics: Compact and lightweight for easy installation and use

Cost and Budget Requirements

Component Cost: Total cost of components should not exceed $50 per unit
Manufacturing Cost: Target production cost of $100 per unit at scale

Project-Specific Requirements

Timeline: Prototype development within 3 months, with a complete product ready for market within 6 months
Team Skills: Team must include expertise in embedded systems, mobile app development, and hardware design

There are a range of skills in this where students can work together on the same project.

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