Electronics production

Introduction:

This assignment focuses on creating and testing a microcontroller development board. The goal is to design a versatile platform for microcontroller applications. Key tasks involve carefully planning the board layout and including essential components like LEDs, resistors, and specific connectors

Research:

EasyEDA

EasyEDA is a free, web-based Electronic Design Automation (EDA) software that allows users to create schematic diagrams, printed circuit board (PCB) layouts, and simulations for electronic projects. It provides a user-friendly interface and a wide range of components and modules that users can use to design and test their electronic circuits.

With EasyEDA, users can design their circuits by dragging and dropping components onto a canvas, and then connecting them together with wires. They can also simulate the circuits to test their functionality and performance, and generate a PCB layout for their circuit design.

EasyEDA also provides a large library of components that users can use in their circuit designs, including microcontrollers, sensors, power supplies, and more. It also has a collaboration feature that allows multiple users to work on the same project simultaneously.

Design process:

1. Initiate a new project:

The inaugural stage involves the initiation of a new project within the EasyEDA environment. To commence this process, navigate to the "File" menu, followed by the selection of "New" and afterward "Project."

2. Searching the components footprints:

In the second phase of the process, I initiated a search within the Common Library for commonly used components, such as LED, FEMALE-HEADER-2.54-SMD-8, and resistors. Subsequently, I used the cloud-connected library to identify additional components like the ESP32.

3. Placing the components and creating connections

Following the placement of components, I used the netflag feature, as indicated by red markings in the accompanying pictures, to establish connections between the components and enhance the overall clarity and organization of the circuit. Subsequently, I utilized the wire function, as illustrated by green markings in the pictures, to further refine and establish the necessary electrical connections within the circuit design.

4. Convert Schematic to PCB and place the electronic components

In this phase, the circuit is transformed into a PCB file by navigating to "Design" and selecting "Convert Schematic to PCB." Following this conversion, the dimensions of the board outline are to be selected. It's worth noting that these dimensions can be adjusted later or even imported as a DXF file. At this point, components are placed on the board as per the desired configuration

5. Establishing Electrical Connections

Continuing with the process, I employed the wiring tool to establish connections between the pads on the PCB, aligning them with the specifications outlined in the schematic. This step involves systematically linking the various components on the board, ensuring that the electrical pathways accurately reflect the intended circuit design

6. Ground Plane and Via Implementation

I employed the Copper Area function to designate specific regions on the PCB where the copper is connected to the GND (Ground) signal. To establish a connection between the GND signal on different sides of the PCB, I utilized vias. These vias serve as conduits, allowing the GND signal to traverse seamlessly from one layer to another, ensuring a well-connected and optimized grounding system throughout the microcontroller development board.

In a parallel process on the second layer of the PCB, I again utilized the Copper Area function to delineate areas where copper is linked to the GND (Ground) signal.

7. Design rule check and 3D-Vizualization

In this step, it is imperative to perform a Design Rule Check (DRC) before proceeding to visualize the PCB in 3D and generating the essential Gerber files required for fabrication. The DRC ensures adherence to design guidelines and identifies potential issues that may impact the functionality and manufacturability of the microcontroller development board. Once the DRC validation is successfully completed, the PCB can be visualized in three dimensions, providing a comprehensive overview of the design. Following this visual inspection, the final step involves generating the Gerber files, crucial documents necessary for the fabrication process.

8. Generating Fabrication Files for PCB Production

In the upcoming phase, the creation of Gerber files is initiated by navigating to "Fabrication" and selecting "PCB Fabrication File," as indicated by the green markings in the accompanying images. Subsequently, the process involves clicking the "Generate Gerber" button, highlighted in red within the pictures below.

Processing the PCB with LPKF

1. Start Process Planning Wizard: I begin by launching the process planning wizard on the LPKF machine interface. This guides me through the initial setup steps.

2. Import Data from a Non-Native Format: I import my PCB design data from a non-native format. I ensure the data is correctly formatted and compatible with the LPKF software.

3. Create an Area for Unnecessary Copper Removal (Rubout): I define the areas on my PCB where unnecessary copper needs to be removed. This process, known as rubout, helps to clear out excess material.

4. Create Fiducials in the CAM View: In the CAM (Computer-Aided Manufacturing) view, I create fiducials. These are reference points used to ensure accurate alignment and placement during the manufacturing process.

5. Generate Insulation and Contour Routing Toolpath: I generate the toolpath for insulation and contour routing. This step involves creating paths for the machine to follow, ensuring precise cutting and insulation of the PCB tracks. Setting: copper layer thickness: 50 µm, Insulation method: partial/full rubout, contour routing .

6. Open Dialog to Edit the Content of the Tool Magazine: I access the dialog box to edit the tool magazine's content. This allows me to manage and adjust the tools that will be used during the PCB manufacturing process.

Tools Used

Conical Tools

Universal Cutter 0.2 mm
Universal Cutter 0.1 mm

End Mill

End Mill 1 mm
End Mill 2 mm

Drilling Tools

Spiral Drill 0.6 mm
Spiral Drill 0.8 mm
Spiral Drill 1 mm
Spiral Drill 1.5 mm

Contour Router

Contour Router 2 mm

7. Start the Production Wizard and Material Setting: I initiate the production wizard and configure the material settings. This involves specifying the type of material I am using and any relevant production parameters.

8. Flip the Board for Second Layer Job: Once the first layer is completed, I flip the board to start the job for the second layer. I ensure the board is properly aligned and secured before continuing.

Results:

The video captures the LPKF machine milling the FR4 PCB. Before milling, I placed the via-rivets and applied a tin-coating. After milling, I performed a manual soldering process, which involves several steps: preparing and cleaning the components and PCB, positioning the components accurately, applying flux, heating the soldering iron to the appropriate temperature, and soldering each connection carefully. Post-soldering, I inspect the joints for quality, clean any flux residues, and conduct electrical tests to ensure proper functionality.

I tested the functionality of an ESP32-S3 chip that I have soldered onto a printed circuit board (PCB). My objective is to interface the chip with a potentiometer, which acts as a variable resistor. As I adjust the potentiometer, I change the voltage input to one of the chip's analog pins. This method allows me to perform an analog-to-digital conversion, which helps me monitor the position of the potentiometer. The data I collect from this test will be used to either control other components or simply to display the readings. This experiment is crucial as it not only confirms the operational status of my chip but also serves as a foundation for future projects that will process sensor data.


// Define the analog pin where my potentiometer is connected
const int potPin = A0;

void setup() {
  // Begin serial communication at a baud rate of 9600
  Serial.begin(9600);
  // Set the ADC resolution to 12 bits
  analogReadResolution(12);
}

void loop() {
  // Read the value from my potentiometer
  int potValue = analogRead(potPin);
  // Calculate the voltage from the ADC value (assuming a 3.3V reference voltage)
  float voltage = potValue * (3.3 / 4095.0);
  // Output the voltage reading to the Serial Monitor
  Serial.print("My Potentiometer Voltage: ");
  Serial.print(voltage);
  Serial.println("V");
  // Wait a bit before the next read
  delay(100);
}

Original design files:

Download Gerber Files

Group Assignment: PCB Production

Here is a detailed explanation of my part of the group assignment, which involves sending the PCB to a production house. This part complements the work done by Michael Bennemann.

This board is an RGBW sensor array which will be used as a sensor for a robot so that it can follow color lines.

Creating a Schematic in EasyEDA

I began by designing the schematic in EasyEDA. This involved selecting the components and defining their connections to ensure the circuit works as intended.

Creating a PCB Design

Once the schematic was completed, I moved on to designing the PCB layout. This step required careful placement of components and routing of traces to optimize the design for manufacturability and performance.

Generating the Gerber Files

After finalizing the PCB design, I generated the Gerber files. These files are essential for PCB fabrication as they contain all the necessary information for each layer of the PCB, including copper layers, solder mask, and silkscreen.

Loading the PCB on the Platform of the PCB Production House

I uploaded the Gerber files to the PCB production house's platform. This step involves selecting the appropriate specifications for the PCB, such as board thickness, material type, and finish.

Exporting and Loading the BOM File

I exported the Bill of Materials (BOM) from EasyEDA and uploaded it to the PCB production house's platform. The BOM file lists all the components that need to be assembled and placed on the PCB.

Checking for Availability of Parts and Replacements

After loading the BOM file, I checked the availability of all listed components. For any parts that were in shortfall, I identified and replaced them with suitable alternatives to ensure the assembly process could proceed without delays.

Final Board Design and Picture

I have later realized that 5V-PIN was not connected to the I2C_Mux that should control the RGBw-Sensors. I have corrected it and made a new production process.

After completing the design and verifying all details, here is a picture of the final PCB design ready for production: