6. Electronics Design

Assignments for week 6:

1. Group Assignment

• use the test equipment in your lab to observe the operation of a microcontroller circuit board

Group assignment link is here

From this group assignment, i got basics of using multimeter. Multimeter is a measuring device that measure electrical properties like voltage, current and resistance.By regulating the rotary switch on the front panel,we can select to measure electrical properties and compare the results.

Oscilloscopes graphically displays varying voltages of one or more signals with functions of time.It is used to visualize the digital signal.

Using the DC power supply test equipment helped me understand that it supplies the constant Direct Current(DC) voltage to electrical devies unlike AC voltage.

2. Individual Assignment

• use an EDA tool to design a development board that uses parts from the inventory to interact and communicate with an embedded microcontroller

• extra credit: try another design workflow

• extra credit: simulate your design
• extra credit: design a case around your design

This assignment started with understanding about EDA tool which stands for Electronic Design Automation.

KiCad as EDA Tool.

Electronic Design Automation is a segment consisting of software, hardware, and services used to assist definitipon, planning, design, implementation, simulation and verification of electronic circuits/systems or chips.You can go to learn more from my reference link here

i have choosed KiCad as EDA tool as i am comfortable with it.

KiCad is an open source software suitable for Electronics Design Automation.This EDA tool handle Schematic capture, and PCB layout with Gerber and IPC-2581 output.

Source reference from here.

Electronics Design using KiCad

Before i start with my design, i have to see about the components required for my final project and follow them for PCB board design.I was instructed to use Xiao SAMD21 as microcontroller.I will be using the components and its pin outs.The components were:

1. Microwave Radar sensor(RCWL-0516) with pin outs-(GND,OUT & VIN.)
2. PIR infrared IR sensor(AM321) with pin outs - (GND,Signal & VCC)
3. PUMP with pin outs - (VCC, GND, Signal)
4. speaker with pin outs - (VCC,RX,TX,GND)

Since the XIA0 SAMD21 was not available while adding components in KiCad, i will be using the XIAO RP2040 as my microcontroller as they have similar pinouts.

image source from here

Working with KiCad.

• Firstly i have downloaded KiCad and installed in my computer.
• I have to add Fab Library which gives access to the Schematic symbols and the footprint of components in the Fab Inventory.So,i downloaded the git repository from this link here and extrated its zip files and renamed as “kicad-master”
• Then, i have opened the KiCad.
• To add Fab Library, i clicked on “Preferences” and choosed “Manage Symbol Libraries” and clicked to add fab.kicad_sym from kicad-master folder.

Choosed to add fab.kicad_sym from ‘kicad-master’ folder downloaded and pasted it.

I repeated same procedure to add the footprint Librarie.I went to “Manage Footprints Libraries” from “Preferences” and added ‘fab.pretty’.

To get started with designing my PCB board, first i clicked on ‘New Project’ under the “FILE” menu.I had to give the file name and save.

Creating the Schematic.

Next, i clicked on ‘Schematic Editor’ and blank drawing sheet was displayed. I had used Add feature to add the required components by choosing mostly from the fab library.

I used some of the quick tricks while adding the components like R to rotate the component, C to copy, M to move, Delate for delate and W to draw wire for connections.So i added all the components that i have listed above keeping in minds their pin outs and had clicked to assign footprints.

While designing the schematic, I have to check for debug or errors in my circuits by using the ‘Electrical Rules Checker’. I observed lot of errors and warnings where i have to check accordingly.

Switching to PCB Editor

Then, i had to start PCB designing.So i clicked on “Switch to PCB Editor” to shift from schematic design.

The schematic editor got into PCB editor.

Now, before i really start with the PCB design, I had to make settings to the design rules like constriants and Pre define sizes and Net classes and these values.

Now, i had to arrange my components to trace. I took lots of time here as it needs more analyzing for placements and made several mistakes.I used few zero resistors which work as jumper wires to connect complicated traces.But my local instructor suggested me not to use zero resistors.

After arranging is done, so i clicked on ‘Route Single Track’ or use ‘X’ key from keyboard to connect my components with trace

To make border for my board, i clicked on “Edge.Cuts” under the “Layers” and selected line to draw as i wanted to my my PCB boarder irregular shaped and was it was connected.

This is how my traced PCB board design with border looked after connecting all the components and shown to my local instructor for feedbacks.

I was suggested by my local Instructor to dirctly connect the ground pins and D2 to connect with another D2 directly. I disconnected between the button as no need to connect and i minimized the trace distance for between the Ground pins highlighted above.

I have added my name on the board by going through the steps.

So this is how my edited PCD design looked.

To look my PCB design in 3D view, i clicked on this icon and it looks this way.

Exporting my files.

To save my desin files for fabrication later, i selected the ‘F.cu’ under layers and went under the “File” and select ‘plot’ with following settings.

I repeated the procedures for Edge cuts.

This is how it looked after the file plot.

1. The zipped file in SVG format for this week is here

2. Design files of KiCad is here

Learning outcomes of the week

By doing this assignments, i have learned to use KiCad as EDA tool for designing my own PCB board, where i mainly worked on Schematic Editor and PCB Editor.I had made several mistakes while doing this and my PCB design may not work when i proceed during Electronic Production week and i would be experiencing to change and edit more to my design.

Working with KiCad was interesting as atleast i knew the process involved to develop the design.