Assignment Brief:

1. Use a multimeter to measure voltage levels and an oscilloscope to analyze signal waveforms on the microcontroller circuit.
2. Reflect individually on what was learned about signal behavior, power characteristics, and troubleshooting.
3. Use an EDA tool to design a development board with inventory parts, ensuring proper power distribution, I/O headers, and communication interfaces.

Electronics Design

This documentation covers essential topics related to microcontroller circuits, electronic components, PCB design, simulation, and testing. By studying these concepts, I learn't how to work with electronic components, design and fabricate PCBs using EDA tools, simulate circuits for analysis, and tested microcontroller-based systems with various lab equipment. These skills are crucial for developing and troubleshooting embedded systems.

Firstly, I familiarized myself with the key terms and references introduced during the lecture on Wednesday. This included understanding various electronic components, circuit design principles, and the use of essential tools like multimeters and oscilloscopes. Below is the documentation of my learning

Microcontroller Circuit

Connectors & Wires

Connectors and wires are essential components in electronics that help establish electrical connections between different parts of a circuit. Wires are conductive materials (usually copper) that carry electrical signals or power between components. Connectors allow easy attachment and detachment of wires and components without permanent soldering.

Ribbon cables are flat, flexible wires used for easy multi-wire connections, often with IDC (Insulation Displacement Connectors) for secure attachment. IDC connectors provide a reliable and quick way to connect ribbon cables to circuit boards without soldering. These are commonly used in microcontroller projects for interfacing multiple components. JST connectors are commonly used in electronics for secure, polarized connections between components, such as battery packs, sensors, and circuit boards.

Passive Components

Passive components are electronic components that do not require an external power source to operate. They simply respond to the electrical signals in a circuit and cannot amplify or control them like active components (e.g., transistors).

• Resistors: Limit current flow and divide voltage, following Ohm’s law (I = V/R).
• Capacitors: Store and release charge, available as unpolarized (ceramic) or polarized (electrolytic).
• Inductors: Store energy in a magnetic field and oppose sudden current changes (V = L dI/dt).

Semiconductors

Semiconductors are materials that have electrical conductivity between that of a conductor (like copper) and an insulator (like rubber). Their ability to conduct electricity can be controlled, making them the foundation of modern electronics.

• Diodes: Allow current flow in one direction (PN, Schottky, Zener, LED).
• Transistors: Transistors are tiny electronic switches that control the flow of electricity in a circuit. BJT (Bipolar Junction Transistor) has three pins: Collector, Emitter, and Base. The Base controls. the transistor, allowing current to flow from the Collector to the Emitter.
• Mosfet: MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor) also has three pins: Source, Drain, and Gate. The Gate works like a switch—when a voltage is applied to it, electricity flows between the Source and Drain. Imagine it like an automatic door—when you press a button (apply voltage to the Gate), the door opens (current flows from Source to Drain).
  MOSFETS are of two types: N-Channel and P-channel, the key difference between the two is, Placement in Circuits N-channel: Preferred for low-side switching (between load and ground). P-channel: Used in high-side switching (between power and load). To know more about what_are_mosfets refer this Link.


Difference between BJT and MOSFET
MOSFET types

Power

Power (P) in electronics refers to the rate at which electrical energy is transferred or converted into another form (such as heat, light, or motion). It is measured in watts (W) and calculated using the formula: 𝑃 = 𝐼 𝑉 P=IV where I is current (amps) and V is voltage (volts). Power is essential for running electronic devices, and it can come from batteries, power supplies, or other energy sources.

• Batteries supply direct current (DC) power, meaning the current flows in one constant direction. They are used in portable electronics, electric vehicles, and backup power systems.
• Voltage Regulators (Stable Power Supply): Regulators ensure a steady and consistent voltage output, preventing fluctuations that could damage electronic components.

Microcontroller & Interfaces

Microcontrollers are compact computing devices that handle both digital and analog tasks, making them essential for embedded systems. They integrate a processor, memory, and input/output (I/O) peripherals on a single chip, allowing them to control various electronic devices efficiently.

Microcontrollers manage digital/analog tasks using GPIO, I2C, SPI, and ADC for communication and peripheral control. In Week 4, of embedded Programming, I worked with the RP2040 microcontroller, a dual-core ARM Cortex-M0+ processor. It features flexible I/O and multiple communication interfaces, making it ideal for real-time applications and embedded projects. Refer to my documentation to learn more about microcontrollers: Embedded Programming.

Peripherals

Peripherals are external or built-in components that allow a microcontroller to interact with the physical world. They enable data collection, processing, and control of external devices, expanding the functionality of an embedded system. Sensors detect environmental changes, actuators convert electrical signals into movement, and buttons/switches provide user input. Some of the microcontroller peripherals are:
1. Sensors (Input Peripherals)

Sensors detect environmental changes and convert them into electrical signals for processing by the microcontroller. Refer to my documentation to learn more about Input Devices: Input Devices

• Temperature Sensors (DHT11, LM35, DS18B20) - Measure temperature.
• Light Sensors (LDR, TSL2561, BH1750) - Detect ambient light levels.
• Motion Sensors (PIR, Accelerometer, Gyroscope) - Detect movement and orientation.
• Proximity Sensors (Ultrasonic HC-SR04, IR Sensor) - Detect objects nearby without contact.
• Sound Sensors (Microphone, Sound Level Sensor) - Capture audio or detect noise levels.
• Touch Sensors (Capacitive Touch, Force Sensitive Resistor) - Detect touch or pressure.

2. Actuators (Output Peripherals)

Actuators convert electrical signals from the microcontroller into physical actions like motion, sound, or light. Refer to my documentation to learn more about Output Devices: Output Devices

• Motors (Servo, Stepper, DC Motors) - Enable movement in robotics and machines.
• Speakers & Buzzers - Generate sounds for alarms, notifications, and audio feedback.
• LEDs & Display Screens (OLED, LCD, 7-segment) - Provide visual feedback.
• Solenoids - Create linear motion, used in door locks and industrial applications.
• Relays - Act as electronically controlled switches for high-power applications.
• Vibration Motors - Provide haptic feedback in mobile phones and controllers.

3. Buttons & Switches (User Input Peripherals)

These allow users to manually provide input to the microcontroller.

• Push Buttons - Trigger actions when pressed.
• Toggle Switches - Maintain ON/OFF states.
• Rotary Encoders - Detect rotational movement and direction.
• Keypads - Provide multi-button input, useful for numeric and text entry.

Circuits & Design

Electrical circuits function based on three fundamental parameters: current (A), voltage (V), and power (P). Electrical circuits operate on current (A), voltage (V), and power (P = I²R = IV). Electrical circuits function based on three fundamental parameters: current (A), voltage (V), and power (P). Voltage (V) is the electrical potential difference that pushes electrons through a circuit, similar to water pressure in a pipe. Current (A) is the flow of electric charge, determining how much electricity moves through a circuit. Power (P), given by formulas like P = IV and P = I²R, represents the rate at which electrical energy is consumed or transferred within a circuit.

Kirchhoff’s Laws – The Foundation of Circuit Analysis

1. Kirchhoff’s Current Law (KCL)

This law states that the sum of all currents entering a node (junction) is equal to the sum of all currents leaving the node. It ensures that charge is conserved, meaning no extra charge accumulates at a junction. Example: In a parallel circuit, the current splits into different branches, but the total entering and leaving remains the same.

2. Kirchhoff’s Voltage Law (KVL)

This law states that the sum of voltages around a closed loop is always zero. It means that the energy supplied by sources (like batteries) is completely used up by components (like resistors, LEDs, etc.). Example: In a simple series circuit with a battery and resistors, the voltage drops across each resistor add up to the total voltage supplied by the battery.

Why These Principles Matter?

Understanding these laws helps in circuit design, troubleshooting, and optimization. These concepts form the foundation of circuit design and debugging, enabling engineers to create stable and efficient electronic systems.

EDA Tools

Electronic Design Automation (EDA) tools are essential for designing and simulating electronic circuits. Software like KiCad, Eagle, Altium, and EasyEDA assist engineers in creating schematics, placing components, routing traces, and generating PCB layouts. These tools automate complex design processes, ensuring efficient circuit board design while following electrical and manufacturing constraints. Advanced features include auto-routing, design rule checks (DRC), and 3D visualization, making them indispensable for both professionals and hobbyists working on custom electronic projects. I will be using the EasyEDA for designing and simulating my electronic circuit. Check my further documentation to got trhought the whole process.

PCB Design

Designing a Printed Circuit Board (PCB) involves several key steps to ensure functionality and manufacturability. The process includes placing components, routing electrical traces, and defining layers to create a compact and efficient layout, as we can do using the EDA tools for building the schematics. To prevent design errors, tools like Design Rule Check (DRC) and Electrical Rule Check (ERC) are used to verify proper spacing, trace widths, and electrical connections. A well-designed PCB improves circuit performance, reduces noise, and enhances reliability in electronic systems.

Simulation & Testing

Simulation & Testing are essential steps in electronic circuit design to verify functionality before physical implementation. Simulation uses software to model circuit behavior under different conditions, helping to detect errors and optimize performance. Testing involves using hardware tools like oscilloscopes, multimeters, logic analyzers, and function generators to measure voltage, current, and signal integrity in real circuits.

Simulation

Falstad, Wokwi, and EveryCircuit are interactive simulation tools that allow users to visually design and test electronic circuits in a user-friendly environment. They provide real-time feedback, making them great for beginners and professionals to understand circuit behavior without physical components. In Week 4, of embedded Programming, I worked with the Wokwi, an interactive simulation tools. Refer to my documentation to learn more about my Wowki software usage: Embedded Programming.

Test Equipment

• Power Supply: Provides stable voltage.
• Multimeter: Measures voltage, current, and resistance.
• Oscilloscope: Visualizes waveforms for signal analysis.
• Logic Analyzer: Captures digital signals for debugging communication protocols.

ERC (Electrical Rule Check) vs. DRC (Design Rule Check)

Some terms I learnt during the process were DRC and ERC. Both are essential for error-free PCB or IC design.
ERC ensures the circuit functions electrically correct.
DRC ensures the design is physically manufacturable.

Feature	ERC (Electrical Rule Check)	DRC (Design Rule Check)
Purpose	Checks for electrical connectivity and logic errors.	Ensures physical design follows fabrication constraints.
Focus	Electrical issues like open nets, short circuits, incorrect pin connections, missing power/ground connections.	Geometric constraints like spacing, width, overlaps, via sizes, and layer rules.
Scope	Logical and connectivity-based errors.	Physical layout errors.
Used In	Schematic design (before PCB layout).	PCB layout and IC design.
Example Errors	Floating pins, incorrect net connections, power/ground issues.	Track width violations, spacing violations, overlapping traces.

Exploring the software: EasyEDA

EasyEDA is a free, web-based Electronic Design Automation (EDA) tool used for designing schematics, PCB layouts, and circuit simulations. It provides a user-friendly interface for hobbyists, students, and professional engineers to create and test electronic circuits online.

Key Features of EasyEDA:

• Schematic Capture – Create and edit circuit diagrams with a vast library of components.
• PCB Layout Design – Convert schematics into PCB layouts and route traces.
• Simulation – Test circuits before manufacturing using built-in SPICE simulation.
• Component Library – Access thousands of components, including custom footprints.
• 3D PCB Viewer – Preview and inspect your PCB design in a realistic 3D model.
• Fabrication & Ordering – Export Gerber files.

EasyEDA Step-by-Step Guide

Step 1: Sign Up & Log In

• Go to EasyEDA.
• Click "Sign Up" to create an account or "Log In" if you already have one.


• Once logged in, click "New Project" to start a new design.
Click On New Project.
Add a folder and create a file.

Step 2: Create a Schematic

• EasyEDA Interface
• Click on "Schematic Design" in the toolbar.


• Use the "Common Library" panel to search for basic components. Click on the component to add to the sheet.


• Use the "Library" panel to search for components (resistors, capacitors, ICs, etc.).

The interface displaying the Library panel, where users can search for electronic components to use in their circuit design. It has a Filter Features in the Library Panel. The understanding of the filter components was a little complex for me, thus I break down thte description for my understanding.

• Types of Components:
  • Symbol: Used in schematic design (circuit diagrams).
  • Footprint: The physical representation for PCB layout.
  • Spice Symbol: Used for circuit simulation (SPICE-based analysis).
  • SCH Module: Predefined circuit blocks.
  • PCB Module: Predefined PCB layouts.
  • 3D Model: View 3D representations of components for mechanical design.


• Classes of Components:
  • Work Space: Components stored in the user's project.
  • LCSC: Components sourced from LCSC, a popular electronic component supplier.
  • JLCPCB Assembled: Components available for JLCPCB assembly services.
  • System: Standard system components.
  • Follow: Favorite or followed components.

  My professor, Pranav Gawde suggested that searching for components is a a difficult task as the name specification and the precision of the component that we need might be different. He added, the LCSC and JLCPCB are the preferred filters for choosing the required component.

• Drag and drop components onto the schematic canvas. Here, I used an RP2040 from the library and placed it on the sheet.


• Place the componenent on the sheet. Later in the process I realised the RP2040 that I choose here was not the proper pin configuration that I required. However, I decided to design a basic circuit schematic for which I used the same XAIO RP2040.


• To understand the basics of EasyEDA, I planned to design a simple circuit using the RP2040 microcontroller, a push-button switch (SW1), and an LED (LED1) with a 1kΩ resistor (R1). Thus, from the common library and library panel I placed all the required components to the sheet.


• Step-by-step connecting required pins to the next to build the circuit. Use the "Wire" tool to connect components.


• Final connections


• Taking reference to the wokwi simulation that I built in Week 4 of the Embedded Programming Week Refer to my documentation,
  Embedding Programming to learn my process. I checked the simulation on Wowki.


• Clicked "Save" when the circuit was done.




Building Schematic to PCB

• Now go to Design> Convert to PCB


• I set the below settings for building my PCB as default> Set Start X and Start Y as Zero> Apply


• Drag the PCB to the centre of Board Outline.


• As the design is not very complex, go to route> auto-route to route the PCB. Routing a PCB (Printed Circuit Board) refers to the process of designing and laying out the electrical connections (traces) between components on the board.

As the circuit is short, I selected only the top layer in the configure layers. The Top Layer in PCB design is the uppermost copper layer where components and traces are placed. It is used for routing signals, power, and ground connections.