7. Electronics design

Due Wednesday March 11 2020

Assessment Requirements

Group assignment

  1. Use the test equipment in your lab to observe the operation of a microcontroller circuit board (in minimum, check operating voltage on the board with multimeter or voltmeter and use oscilloscope to check noise of operating voltage and interpret a data signal)
  2. document your work (in a group or individually)

Individual assignment

  1. Redraw one of the echo hello-world boards or something equivalent, add (at least) a button and LED (with current-limiting resistor) or equivalent input and output, check the design rules, make it, test it.

Learning outcomes

  1. Select and use software for circuit board design
  2. Demonstrate workflows used in circuit board design

Have you? Check Table

Have you? In Process Done
linked to the group assignment page
Documented what you have learned in electronics design
Explained problems and how you fixed them, if you make a board and it doesn’t work; fix the board (with jumper wires etc) until it does work.
Included original design files (Eagle, KiCad, - whatever)
Included a ‘hero shot’ of your board
Loaded a program and tested if your board works

FAQ

Can I modify an existing design board?

Answer: No, you have to create your board from scratch.

Do I need to create a schematic file?

Answer: Yes, at least for this week.

Can I draw my design by hand?

Answer: Yes, but you have to use EDA software for this week.

Getting Started

I was a bit freaked out by this weeks assignment, I haven’t done any electronics CAD design before except for modifying existing eagle designs. Oddly I have fabricated a milled 555 timer circuit for a circuit bending workshop led by Patrick McCarthy back in 2011. Our 555 timer circuit was designed and fabbed hacker style skipping eagle or other circuit design software completely by using the following steps:

  1. Hand draw circuit based on point to point wiring of 555 timer circuit used in previous circuit bending workshops
  2. 3D modeling this circuit in SolidWorks (which allowed easy graphic customization)
  3. Exporting the 3D CAD file to a 3D DXF file
  4. Importing the 3D DXF file into Modela MDX-20 carving software (on Windows XP or 7?)
  5. Milling the circuit on the Modela as if it were a regular milling job.
  6. Milling a total of 20x boards for our Circuit Bending workshops.

Fast forward 9 years later and my goals for Electronics Design in our Fab Lab is motivated by:

  1. Open source software design and fabrication process flow (no cost non open source software will be used if it is much easier to use by students)
  2. Easy 1st and 2nd electronics design experience for students who have just learned Tinkercad
  3. Simplify the design process, but still learn concepts for advanced electronics cad (Kicad and eagle cad)
  4. Make the process of milling a board easy (X-Carve or MDX-20)
  5. Keep the design to fab time 1 hour max (with support from fab lab staff for the 1st board yellow belt level on grid)
  6. Keep the design to fab time for second board to 2 hrs max (orange or green)

Could I use some of the techniques above for this weeks work? It has always seemed over kill to use eagle to make single sided circuit boards. I do think that milling circuit boards is pretty fun, but the design process and electronics design software has a horrible learning curve for me and will for my students. This week I want to explore how to scaffold learning of electronics design. I would prefer to go from hand drawn sketches to a milled board in way that still allows students to learn the concepts needed for more advanced electronics design later.

Looking at 2019 Fab Academy students work revealed that others have followed similar processes. I found the following student pages the most informative via the google custom search at: https://fabacademy.org/2019/

  1. http://fab.academany.org/2019/labs/tecsup/students/diego-meono/week7.html
  2. http://archive.fabacademy.org/2019/labs/cept/students/samiul-hoque/assignments/week7.html

In future session or if I have time this week I will try Kicad. It’s open source and runs on Linux locally. This 2019 BCN tutorial may help me get started with Kicad. It appears that the FAB library can be imported as well, so that is quite powerful. If Kicad is too hard to learn I may revert to Eagle, since it seems to have a longer history of use in Fab Academy.

  1. Introduction to KiCad I started the official Kicad tutorial and it’s pretty easy to follow!
  2. BCN: Kicad Electronics design

I am realizing that i may want to downgrade to a simpler isp programmer compared to the ARM JTAG I did during 05 Electronics Production. One of the boards suggested, with guides in the 2019 tutorials will be a better choice: https://fabacademy.org/2019/docs/FabAcademy-Tutorials/week04_electronic_production/fabisp_models.html

KiCad on Linux

I initially tired KiCad version 4.0.7 installed via my package manager, and it had weird graphics artifacts on my Linux PC. So I tried the 5.1.5 Stable Release. I used this guide to properly install KiCad. This worked.


Archive

Eagle CAD on Linux

I got the following error after trying to run Eagle:

~/Apps/eagle-9.5.2$ ./eagle run<

Resulted in:
./eagle: symbol lookup error: /usr/lib/x86_64-linux-gnu/libGLX_mesa.so.0: undefined symbol: xcb_dri3_get_supported_modifiers<

So I searched online for a solution and found: EAgle Forums: libGLX_mesa.so.0: undefined symbol: xcb_dri3_get_supported_modifiers
So I tried it:

~/Apps/eagle-9.5.2$ rm libxcb-dri3.so.0<

It worked and EAGLE launched! Thanks angelblizard! However the licensing nature of installing Autodesk products and the requirement of an account is bull****. I am now using KiCad as my main electronics design software.

  1. 2019 Eagle CAD Tutorial

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