Electronics design 2.0

Group assignment

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

Here you can check the electronics design grop assignment

individual sssignment

Redraw an echo hello-world board, add (at least) a button and LED (with current-limiting resistor) check the design rules, make it, and test it extra credit: simulate its operation

individual assignment

As always this assignment is divided on several parts

My 2020-2021 efforts
Generalities on ECAD design
TIPS AND TRICK ON EAGLE
BOM
conclusion
Links and references

My 2020-2021 efforts

as i Stated in earlier assignments i started this journey to certification on 2020 and didn't met the requierements. then passed on 2021 and also didn't get to finish altough got to present my final projet.

So today in 2022 i've got to re write several of my original assignments.

HERE You can check what i did on 2020-2021 Electronics design assignement

Generalities on ECAD design

HERE on Mexico is not that common to find places to learn ECAD (electronical Computer aided design) altoguh it has similarities to conventional CAD it is completly diferent branch of design and workflow.

It is more common to find places were you can learn arduinos and conventional prototyping (using breadboards and simulators) than places were you can learn how to machine your own boards.

And to go even further, it's really dificult to find certain SMD components because all of the traditional fabrication methods use Trough hole technology (THT) because it has more room to error cause the components are bulkier and they're not so prone to make short circuit with out it has to be obvious.

Anywho....

Let's talk about the ECAD in general. I've tried a little bit of Fritzing, Altium and the original EAGLE.

Altough kicad is open-source really the standard on an industrial enviroment is EAGLE so i try to teach things that are more usefull on a real work enviroment.

Altough kiCAD is a piece of CAD i would like to really master some day.

Today i'm stuck with the conventional licensed and boring ECAD.

On 2020 i started my designs on Autodesk's EAGLE.

In that time you could download a Stand alone version of the software using the educative account on autodesk's page.

during 2020 outbreak had "technical dificulties" with my laptop. So had to reinstall eagle on a new laptop

then i realized that it is not possible to install only eagle anymore.

i do not know who was the genious behind that idea.

but now you have to install a mechanical CAD/CAE tool to have eagle.

it's like having 3 softwares installed all at once.

it's heavier to run on a regular laptop altough it's cheaper on a long run just to pay for 1 license than to pay 3.

Fusion 360 it's the new enviroment for CAD on eagle

Anyway, after you finish the installation. open up Fusion 360 you'll have to go to file/open electrical design in order to get to the forst step of eagle wich is open up a project or create a new one.

Whats a project?

it's an special type of file that's the link or bond between 2 diferent types of files in eagle the scheme (*sch) and board (*brd) files. Each one has it's own workflow whitin. Altough you can do really complex things like PC motherboards with multilayer boards, gnd and noise shielding. i only know how to engrave the first layer.

create a new scheme (red circle) link an existing (brown circle) for when you're downloading schemes from other person and you get the "no relation between sch and brd" error.

beacuse of my mechanical design background i'm gonna make this analogy frecuently.

in a SCH the polylines are called nets and the can be in two diferent types explicit or implicit (visible or invisible) they set logical conections between components.

i based my design on adrian torres samdino because i want to used this board to input devices, output devices networking & comm and interface and appilications.

adrian's samdino

al tough i generaly speaking i think he did a great job i modify it a little bit to make it a little clearer

First he has a gnd trace in between 5vdc and 3.3 vdc on the lineal voltage regulator that's to tight not for the cnc but for my soldering skills. so y placed a 0 ohm resistor to be a jumper just to make sure the regulator does not have a solder bridge.

then adrian has smd jumper wire female conectors and and for me that's usually a big no no in design because the cooper pads are just to fragile to make them take mechanical stress of conecting and disconecting things.

Also i removed the voltage regulator to feed with a 9V battery.

and placed extras 5v and 3.3v vcc as well as gnd.

the general workflow on the SCH files it's kinda like this.

Open a new Scheme
Place components
set nets
set names and/or values to the nets and components
go to create the board file

this is my SCH file

HERE you can download my EAGLE FILES

in the button shaped like a pcb board you can change the view to board file (ctrl+2)

in the BRD files the nets becomes airwires (it makes nosense to me but however.)

then the general workflow on a BRD file i't like this.

Edit the DRC (design rules check)
Place all of the components inside the default pcb dimension.
orient all of the components in a way that makes sense.
Draw all of the essential airwires manually
then auto route the rest of the airwires.
try to make sense out of even the lines(they have to be clear to see were they conect and how they conect.)

neil only talks about SMD components but as i said before it's really dificult for me to get all of the required components in time from an international vendor like digikey. it's easier to go to the local electronic store and get 50 THT 1Kohm resistors than to wait 2 weeks to get them in SMD version from digi-key.

So it's logical to simply draw components that are THT or SMD depending on what i have in stock in the inventory on the fablab.