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Week 6. Electronics Design

This week we were introduced with lot more complex electronics components that are present in the lab. In addition to that we were also made familiar with all the components that we will be using for the Final project so for that first we learned how to create our own circuit board using PCB designing software known as Kicad and For this week and throughout my FAB academy I will be using KICad for designing PCB as it is quite user friendly and on top of that I am quiet comfortable with KICad compare to other PCB designing softwares.

Group Assignment:

  • Use the test equipment in your lab to observe the operation of the micro-controller in a board.

Link to the group assignment is here

Key takeaways from this week:

  • Oscilloscope is a great tool to visualise your work through waveforms.

  • Always follow the instrument manual when using any instrument.

  • Always make sure and ensure the connections are being made properly and to right port while designing circuit and doing it manually with components.

  • Multimeter is a device which can be used to measure voltage, current and resistance of an electric circuit.

  • Function generator is an electronic device which is used to test and simulate signals in electrical and electronics circuits. And it produces standard waveforms, such as sine waves, square waves and triangle waves.

  • Dc power supply is used to step down the 230V AC supply to required dc power supply to test components.

Individual Assignment:

  • Design a development board to interact and communicate with an embedded micro-controller.

KICad

KIcad is a open source software which allows individual to do PCB milling and automation. It is user friendly as it allows the user to check any error in the circuit and proceed further before actually milling the PCB.

Steps to Use KIcad

  • I Downloaded KICad

  • After that I added Fab Library in KICad from the git repo and for that I followed some of the steps mentioned below:

  • To add Fab Library download it or clone from Fab library and rename the directory to the fab.

  • Open KICad, go to Preferences on the Menu Bar and click on Manage Symbol Libraries and add fab.kicad_sym as symbol library and click OK.

  • Next go to Preferences on the Menu Bar and click on Manage Foot print Libraries and and add fab.pretty as footprint library and click OK.

  • Lastly again go to Preferences on the Menu Bar, click on Configure Paths and add variable named FAB that points to the installation directory of the fab library, such as ~/kicad/libraries/fab or C:/kicad/libraries/fab. This will enable the custom 3D shapes to be found. The 3D shapes project has just started and most of them have to be populated still.

Individual Assignment

For the Individual Assignment we were told to design development board which can communicate with an embedded micro-controller. Since I had decided to use XIAO RP2040 for my final project I had chosen RP2040 only because I thought it will be helpful for me as I proceed further with my final project and also I thought I will be getting used to it and later on I won’t be facing any difficulties.

Creating Schematic design using KICad

  • I opened the KICad, clicked on the File on the menu bar,clicked on the New project and saved my file by giving its name. So after doing that my schematic and PCB files will be created.

  • After that I double clicked on the schematic editor which will open our saved project file and allows us to create and design the circuit design for the PCB.

  • I started designing my circuit board by adding necessary components from the libraries for that I typed ‘A’ key from the keyboard or by clicking on the arrow like symbol which is available on the right hand side tool bar of kicad.

Since I am working with Xiao RP2040, I typed its name from the libraries and imported it into the schematic canvas or workspace by selecting it and chosing the right footprints for the components.

Similarly next I added LED and resistors for my development board and I had taken the same steps

Followed by that I added switch and connector pins

After I added all the components, I started to connect all of them by selecting Add Wire(W) from the right hand side toolbar and I made the connection as shown below:

Then I checked whether there is error in my design or not by selecting Electrical Rules Checker (ERC) which is on the Tool bar and found that there are few warnings in my design.

Since I didn’t connect some of the serial communication protocol pins with the micro-controller so that’s why there was warnings in my circuit design. So for that I had given connection for the serial communication protocol pins and once again clicked on Electrical Rules Checker (ERC) and found out that all of my warnings were gone.

Next to open the PCB Editor go to ‘Tools’ on the Menu Bar and click on switch to PCB Editor or you can directly open it by clicking on the icon which is located on the extreme end of Tool bar.

After that the PCB layout editor will be launched where we can place our components and design our PCB. If incase we have added new components in schematic circuit and in order to update in the PCB editor we just need to click on Update PCB from Schematic to bring in all components and their footprints. Then I started arranging the components and started routing the connections using traces(tracks).

I configured design rules and constraints under Edit Board Setup >> Design Rules >> Constraints, specifying parameters like minimum clearance, etc and also I gave pre-difined sizes for tracks.

And I clicked on Net classes and added some parameters there also.

Next I went for Design Rule Check(DRC) for my circuit design to ensure there is no any errors in the circuit design.

After that I had exported the board area(Routing area) into SVG format and for that I had selected F.Cu layer.

Followed by that I also exported the edge cut into SVG format by selecting the B.Cu layer.

Next step I tried adding 3d models in my components so for that I selected my components and pressed E key and selected the required footprints of 3d models for my board.

I added 3d models to all the components and finally this is how my board looked like in 3d view.

Files for the week

Download the circuit design files from here

As I am completely new to electronics,I faced lot of difficulties while tracing my circuit using kicad but nevertheless I was able to trace it with guidance and support from my instructor and friends. As always it was nice and fun in learning different electronics equipments in group.