6. Electronics Design¶

This week, I explored the fundamentals of electronics design by creating a custom development board using EasyEDA. The assignment required designing a functional PCB that could interact and communicate with an embedded microcontroller.

Part 1: Group Assignment¶

Me and Samrudhi worked together as a group to do this assignment. As part of the this , we used test equipment to analyze the operation of a microcontroller circuit board. The main tools we used were:

Oscilloscope Testing¶

What is Osciloscope?

An oscilloscope is a tool used to visualize electrical signals in a circuit. It displays how voltage changes over time in the form of a graph, helping to analyze signal behavior, detect noise, and debug electronic circuits.

The osciloscope which we had in our lab was Tektronics tbs2000 seriers

Understanding the Basics of an Oscilloscope¶

An oscilloscope graphically represents voltage signals over time. The horizontal (X-axis) represents time, while the vertical (Y-axis) represents voltage. By connecting an oscilloscope to a microcontroller, we can monitor how signals change, identify errors, and measure key parameters.

Grid (Divisions)

The oscilloscope screen is divided into a grid of 15 horizontal and 10 vertical divisions.

Horizontal Axis (Time/Div): Represents time per division. Vertical Axis (Volts/Div): Represents voltage per division. The number of divisions helps visualize signals with precise scaling for measurement.

Panels

The oscilloscope has three main control sections:

Panel	Function	Description
Vertical Panel (Voltage Control)	Volts/Div	Adjusts voltage scale per division.
	Position Knob	Moves waveform up/down.
	Channel Selection	CH1 or CH2 selection.
Horizontal Panel (Time Control)	Time/Div	Adjusts time scale per division.
	Position Knob	Moves waveform left/right.
	Record Length	Captures up to 20M samples.
Trigger Panel (Signal Stability)	Trigger Level	Defines capture voltage threshold.
	Edge Trigger	Captures rising/falling edges.
	AutoTrigger (AutoSet)	Stabilizes waveforms automatically.

In the oscilloscope itself, there is a feature called Scope Intro that helps you understand the basics. It is useful for beginners who want to quickly learn how to operate the device.

How to use a Oscilloscope

Power on - Connect the Oscilloscope to the power scouce and switch it on by pressing the power button
Connecting Probes - To start, connect the probe to the circuit. One end goes to the signal you want to measure, and the other connects to the ground.

3.Setting Voltage and Time - Adjust the voltage (Volts/Div) and time (Time/Div) settings to get a clear view of the signal. To do this you can directly Auto set it by pressing Auto Setup key or you can manually do it by adjusting the vertical and horizontal controls form the panel.

4.Triggering - The waves you see should be square waves and should not move continuously. To stop the movement and get a perfectly rectangular wave, use the trigger function. This helps stabilize the waveform on the display.

Sometimes, the signal may appear slightly misaligned due to over-powering or under-powering. To correct this, use a screwdriver to adjust the small screws on the oscilloscope. There are two adjustment points—one for increasing and one for decreasing.

Note: The coupling setting in Channel 1 determines how signals are processed. DC coupling lets both AC and DC signals pass, while AC coupling blocks DC, showing only AC variations. This helps in analyzing the right signal type in your circuit.

Testing a microcontroller¶

We are going to test the ATtiny85 circuit which was made during embedded programming module (week 04)

Part 2: Understanding the PCB design software¶

There are several PCB design software options available such as KiCAD, EasyEDA, Autodesk Eagle,etc. These software tools help in designing and simulating circuit boards before fabrication. Each software offers features like schematic design, PCB layout, component placement, and routing.

Before jumping in, our mentor Jesal Sir gave us a quick tour of Eagle in Fusion 360. It’s a powerful tool, but a bit complex for beginners. So, we decided to start with EasyEDA instead—it's beginner-friendly and keeps things simple.

EasyEDA allows both schematic design and PCB layout in a single platform. It also provides a large component library and an easy-to-use interface for routing traces and checking design errors. Our Fab Lab mentor, Pranav Sir, guided us through the basics of EasyEDA. His session helped us understand the workflow of PCB design.

You start of by downloading the software. Link to download. Once the software is downloaded create a new login.

Once logged in start a New project.

This is what the basic interface of the software looks like.

I wanted to make a breakout board by exposing all the pins and add extra pins for 5V, GND, 3V3, I2C and SPI.

Schematic Design¶

To start with the design click on Schematic Design in the toolbar or use the Library panel to search and add components

You can import the basic elements from the Common library

I started off with RP2040 - the microcontroller. Confidently, I picked an RP2040 from the library and started wiring everything up.

Later I realized I had selected the wrong RP2040 variant! The one I initially picked had different pins—GND, RST, SWCLK, and SWDIO—while the actual module available in our lab had a different pinout and a connector space at the top. So, I had to go back, remove the incorrect component, and start fresh.

Lesson learned: always double-check component footprints before diving into wiring!

After fixing the above problem I selected the correct RP2040 from the library and placed it on the canvas.

Then I started adding all the main componenets which I require on my canvas.

Challenge: One of the main challenges I faced was searching for the right components in EasyEDA. The library is huge, and sometimes the exact name or specifications of the component I needed didn’t match what was available. This made it tricky to find the right parts for my schematic.

To make things easier, Pranav Sir suggested using the LCSC and JLCPCB filters while searching. These filters helped narrow down the options and made it much faster to find compatible components

Once you select the components from the library you just have to drag and drop it on your canvas.

Once I had all the required components on the canvas, the next step was to wire them properly. EasyEDA makes wiring simple—you just have to click on a pin and drag a connection to the corresponding component.

I have used No Connect Flag to mark the points which has no connection

This is what it looks like after wiring all the components

PCB Layouting¶

Once the schematic was complete I went to designing my PCB layout. To do so go to Design > Convert schematic to PCB

Once you convert a dialogue box appears and you can to specify the board dimensions.

You can define the design rules or can keep it as default

Once that is done Auto-Route to generate paths

What does Auto route do?

It automatically connects the components on a PCB layout based on the schematic. Instead of manually routing traces (wires) between components, Auto-router tries to find the best path for connections while following design rules like trace width, clearance, and layer constraints.

Error: As i hit on run an error popped up mentioning that my components are not inside the net. I moved my components withing the boundary and did auto routing of the paths again

The first time I ran the auto route 2 out of 54 paths failed.

The blue lines overhere are unrouted connections (also called airwires or ratlines). To fix this I have to manually routes those connections.

To solve this i tried untangling the components and rearranging them again

Hero shot

BOM¶

You can also generate BOM to order all the components. To do this go to Fabrication > BOM > Export BOM

Gerber¶

To generate a Gerber file check if everything is connected properly by running Design Rule Check (DRC) under Design > Check DRC.

If there are no errors, click Fabrication Output or Generate Fabrication Files—this will show a preview of your board. Once you're happy with it, hit Generate Gerber, and EasyEDA will give you a .zip file with all the details.

3D Renders¶

You can also view the 3D render of your PCB! Simply go to View and select 3D View

Hero shot