Week 06 — Electronics Design

Documentation

This week I focused on learning a complete electronics design workflow for a small embedded board. I first tried several EDA tools, then chose EasyEDA for this assignment, built a schematic around the XIAO ESP32-C3 form factor, added a button and LED as input/output components, checked the fabrication rules, and exported the final board for production.

Group Assignment

Use the test equipment in your lab to observe the operation of an embedded microcontroller.

Individual Assignment

Simulate a circuit.
Use an EDA tool to design an embedded microcontroller system using parts from the inventory, and check its design rules for fabrication.
Extra credit: try another design workflow.
Extra credit: design a case.

Trying Different EDA Tools

I started by installing KiCad and the Fab library plug-ins. The installation itself was straightforward, but the environment felt unfamiliar and I could not move quickly yet.

KiCad installation screenshot — Figure. KiCad installation and Fab library setup.

KiCad Fab library installation — Figure. KiCad installation and Fab library setup.

KiCad environment after setup — Figure. KiCad was installed correctly, but the workflow still felt unfamiliar.

I also installed Autodesk Eagle, but the result was similar. I understood that I would need much more time to be comfortable in that interface.

Autodesk Eagle download page — Figure. Eagle installation and first look at the interface.

Autodesk Eagle interface — Figure. Eagle installation and first look at the interface.

After a workshop with classmates, I switched to EasyEDA. For a first electronics design assignment, the online workflow felt much easier to understand. I also looked at LCEDA and existing Fab Academy examples to understand what kind of board I wanted to make.

Reference board example from Fab Academy — Figure. Reference board research and comparison of LCEDA and EasyEDA.

LCEDA interface — Figure. Reference board research and comparison of LCEDA and EasyEDA.

EasyEDA related links and libraries — Figure. EasyEDA project structure starts from the schematic and then leads to the PCB.

EasyEDA project structure with schematic and PCB — Figure. EasyEDA project structure starts from the schematic and then leads to the PCB.

Board Concept: A Universal XIAO Carrier

My idea was to design a PCB that can hold different XIAO boards with the same form factor. The exact chip can be different, but the footprint is similar, so a small carrier board with headers, an LED, and a button can be reused for several boards.

I used Adrian Torres's Fab XIAO project and the official XIAO ESP32-C3 documentation as references. I compared the board pinout, the schematic representation, and the real physical layout to understand how the pins should be mapped.

Fab XIAO reference project — Figure. Researching the XIAO family and finding the right component in EasyEDA.

Seeed XIAO pinout reference — Figure. Researching the XIAO family and finding the right component in EasyEDA.

Selecting the correct XIAO part in EasyEDA — Figure. Comparing the EasyEDA symbol with the official XIAO documentation.

XIAO ESP32-C3 schematic in EasyEDA — Figure. Comparing the EasyEDA symbol with the official XIAO documentation.

XIAO documentation link — Figure. Documentation and design references used for the universal XIAO carrier concept.

Universal XIAO board reference — Figure. Documentation and design references used for the universal XIAO carrier concept.

Comparing schematic and physical pin positions — Figure. The schematic view and the physical board view are different, so careful pin mapping is important.

Pin counting direction around the board — Figure. The schematic view and the physical board view are different, so careful pin mapping is important.

Building the Schematic First

A PCB in EasyEDA starts from the schematic. I first placed the XIAO symbol, then generated the PCB from it and continued editing only through the schematic whenever I needed to change the logical connections.

Generate PCB from schematic button — Figure. The PCB is generated from the schematic, not the other way around.

Update schematic to PCB dialogue — Figure. The PCB is generated from the schematic, not the other way around.

2D PCB preview in EasyEDA — Figure. EasyEDA can immediately show both 2D and 3D views of the generated board.

3D PCB preview in EasyEDA — Figure. EasyEDA can immediately show both 2D and 3D views of the generated board.

The next step was to add pin headers. Because I wanted to support the XIAO footprint, I needed a one-row, seven-pin header with 2.54 mm pitch. This standard pitch is a common electronics connector size.

Pin header category in EasyEDA — Figure. Choosing the right header count and 2.54 mm package.

Selecting a 1x7 header — Figure. Choosing the right header count and 2.54 mm package.

2.54 millimeter pitch explanation — Figure. Component orientation and basic schematic wiring tools.

Rotating and flipping components — Figure. Component orientation and basic schematic wiring tools.

I tested two connection methods. The first was drawing wires manually. The better method was using unified net names, because the schematic stays cleaner and the logic is easier to understand.

Connecting pins by touch in the schematic — Figure. Wiring by hand works, but named nets are cleaner and easier to manage.

Unified net naming in EasyEDA — Figure. Wiring by hand works, but named nets are cleaner and easier to manage.

Importing schematic changes into PCB — Figure. After changing the schematic, the PCB can be updated and checked again in 3D.

3D PCB view after updates — Figure. After changing the schematic, the PCB can be updated and checked again in 3D.

Matching the Footprints

When I first generated the board, the header positions did not match the actual XIAO board location. I had to compare the footprints against the official documentation and then move or modify the footprint so the board would align with the real hardware.

Header placement not matching the XIAO board yet — Figure. The first PCB placement did not align with the real XIAO footprint.

Footprint menu in EasyEDA — Figure. The first PCB placement did not align with the real XIAO footprint.

Footprint details in the documentation — Figure. I used the documentation as the reference to correct the board footprint.

Modified footprint based on documentation — Figure. I used the documentation as the reference to correct the board footprint.

Adding an LED and Button

To satisfy the input/output requirement, I added an LED and a pushbutton. For the LED I also added a resistor as a current-limiting resistor. I used 1206 SMD components, because they are large enough to handle more comfortably during a first board design and later soldering.

Adding LED component in EasyEDA — Figure. Adding the LED and choosing a 1206 resistor package.

Selecting 1206 package — Figure. Adding the LED and choosing a 1206 resistor package.

Reference schematic with LED and resistor — Figure. I checked reference schematics for both LED and button connections.

Pushbutton article reference — Figure. I checked reference schematics for both LED and button connections.

The button connection needed more attention, because it can easily create a wrong or unstable circuit if it is wired carelessly. I followed the reference logic and kept in mind that the XIAO board works at 3.3 V, so the external circuit should also stay within that limit.

Button circuit logic and resistor placement — Figure. Button logic, component choice, and the reminder to stay within 3.3 V limits.

Pushbutton selection in EasyEDA — Figure. Button logic, component choice, and the reminder to stay within 3.3 V limits.

Single-sided SMD board approach — Figure. I kept the design as a single-sided SMD board for easier fabrication.

Design Rules for Milling

After the functional schematic was ready, I shifted to fabrication constraints. For PCB milling I needed to think about the two exported files, the board material, the milling bit diameter, and the minimum spacing between pads and traces.

Two exported files for PCB production — Figure. The board needs separate logic for copper traces and the outline cut.

Traces and outline file explanation — Figure. The board needs separate logic for copper traces and the outline cut.

FR1 and FR4 board material note — Figure. Material choice and the design-rule setup stage.

Opening design rules in EasyEDA — Figure. Material choice and the design-rule setup stage.

Based on the milling constraints, I used 0.4 mm as a safe value for spacing and treated that as the minimum practical clearance for this beginner board. I also reviewed stroke width and track settings so the board would be easier to fabricate.

Setting 0.4 millimeter spacing in design rules — Figure. I used conservative values and set the main rules to 0.4 mm.

Applying 0.4 millimeter values across the rule set — Figure. I used conservative values and set the main rules to 0.4 mm.

Top, bottom, and board outline layers — Figure. Preparing the layer set and drawing the board outline.

Drawing the board outline — Figure. Preparing the layer set and drawing the board outline.

Routing the Board

While routing, I kept the traces as far apart as possible and avoided sharp 90 degree corners. I changed the working width to 0.254 mm and used autorouting as a starting point, then reviewed the result manually to make sure the paths were still reasonable.

Changing track width to 0.254 millimeter — Figure. Trace width, routing rules, and autorouting configuration.

Routing advice about spacing and 45 degree turns — Figure. Trace width, routing rules, and autorouting configuration.

First autorouting result — Figure. Reviewing the routed board and checking the clearances for soldering.

Adjusted routing result — Figure. Reviewing the routed board and checking the clearances for soldering.

DRC, Export, and Final Board

Once the board looked complete, I ran design rule checks and then exported the fabrication data. EasyEDA reported two errors, but these were related to the LED setup and not to the overall board layout. The production output is a Gerber package that can be sent to a PCB manufacturer directly.

Export menu in EasyEDA — Figure. Export and DRC checking before production.

Design rule check in EasyEDA — Figure. Export and DRC checking before production.

Export options for fabrication — Figure. Preparing the Gerber output and checking manufacturing options.

PCB manufacturer integration in EasyEDA — Figure. Preparing the Gerber output and checking manufacturing options.

Board options such as flexible PCB — Figure. Fabrication options and production cost preview.

Manufacturing quotation window — Figure. Fabrication options and production cost preview.

Final board schematic view — Figure. Final schematic, 2D PCB layout, and 3D board preview.

Final 2D PCB layout — Figure. Final schematic, 2D PCB layout, and 3D board preview.

Final board design overview — Figure. Final electronics design result for Week 06.

Reflection

The main thing I learned this week is that electronics design is not only about drawing a board shape. The real workflow starts from the schematic, then moves through footprints, placement, routing, fabrication rules, and final export. I also learned that documentation and official pinout references are essential, especially when the schematic symbol and the physical board layout do not look the same.

KiCad and Eagle are still worth learning, but for this first pass EasyEDA helped me understand the sequence more quickly. The most important practical lessons for me were using named nets, checking footprint dimensions against documentation, staying conservative with clearances, and always running DRC before export.