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###Week5: Electronic Design
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###Design
This week has reached the peak of the learning curve.
I'm a total beginner at electronics, and it took me 4 days to tweak around the software.
At first, I couldn't install either KiCad or Eagle smoothly due to the compatibility with my MAC version.
This issue forced me to upgrade my system from 10.13 High Sierra to 10.15 Catalina.
Then, I chose to dive into Eagle just because I think it would be great to integrate 3d modeling purposes in Fusion360, plus, the interface looks more pleasant to me.
I picked <a href="http://academy.cba.mit.edu/classes/embedded_programming/D11C/hello.D11C.blink.png">ATSAM D11C</a> as my reference board.
In schematic, I tried to mimic how components are connected with each other, but found it really nasty.
After struggling back and forth between schematic and board view, I gradually adapted to a cleaner way: separating all the components apart, just to name the wire of each component its 'neighbor component'.
Since in any way the board view would automatically connect the wire for you based on how you name the wire, aka, who goes to who.
<img src="./A1.jpg" alt="strandbeest" width="1000"/>
<img src="./A3.jpg" alt="strandbeest" width="500"/> <img src="./A4.jpg" alt="strandbeest" width="500"/>
###Fabrication
This process was an absolute pain. I exported the file to 1000dpi png in Eagle,and then imported it to MODS with 1000 dpi as well.
It ended up fabricating a twice big board, which took me about 20 min to mill it.
After consulting with Nathan and Rob, for '<a href="https://www.apple.com/macbook-pro-13/">MAC</a> + <a href="https://www.autodesk.com/products/eagle/blog/fusion-360-integration-eagle/">Eagle</a> users,
you have to import 2000dpi in MODs to make it fit the original size.
The take-away is that always double-check the dimension before launching the fabrication.
Another issue is about milling the boundary, either the mill cut through the inner circuit, or it cut too close to the edge so that some of the close-to-boundary-copper got cut off, thus causing the disconnection.
To solve that I decided to use jumping wire at the moment, and let others using the milling machine (as I claimed the machine for almost 2 hr!).
<img src="./B1.jpg" alt="strandbeest" width="500"/> <img src="./B2.jpg" alt="strandbeest" width="500"/>
<img src="./B3.jpg" alt="strandbeest" width="500"/> <img src="./B4.jpg" alt="strandbeest" width="500"/>
###Soldering
Due to the soldering training two weeks ago, I feel I'm more confident on it this time.
I somehow get the trick, where I always put some solder first, then attach the components while melting it.
I found it more comfortable to not use the microscope but my bare eyes.
I also notice that using the clamp is a lot easier to solder, as you can place the board at any orientation, not just z=o.
As shown in the below photo, there's a jumping wire due to some cut-off copper wire problem that I was not able to trouble-shooting yet.
If I get time, I will export a cleaner, offset boundary file directly from eagle, rather than post-edit in photoshop to add more background offset.
<img src="./C1.jpg" alt="strandbeest" width="1000"/>
<img src="./C2.jpg" alt="strandbeest" width="1000"/>
<img src="./C3.jpg" alt="strandbeest" width="500"/> <img src="./C4.jpg" alt="strandbeest" width="500"/>
###Testing and Bootloader
Using a <a href="http://fab.cba.mit.edu/classes/MAS.863/Harvard/people/GabbyPerry/static/Multimeter.jpg">multimeter</a> to test the resistance and voltage is the first step before bootloader the board.
So, I got bad luck again. When I connected the GND from the USB to the regulator, there's no 'bee' sound from the multimeter.
Then Rob helped me troubleshoot, we found two problems. The major failure is that I drew the wrong pin 'SWDCLK'. After checking the <a href="http://fabacademy.org/2020/labs/leon/students/adrian-torres/samdino.html">datasheet of D11C</a>, I understand that the pin SWDCLK should be at the pin below RESET, which is pin PA30.
The other minor failure is the wire didn't cut through or got cut off, which I can easily fix with jumping wire.
For bootloader the board, I haven't got a chance to do it due to those issues.
However, Rob kindly did a write-up for <a href="https://raw.githubusercontent.com/qbolsee/ArduinoCore-fab-sam/master/json/package_Fab_SAM_index.json">bootloader SOP</a> and I also found <a href="http://fabacademy.org/2020/labs/leon/students/adrian-torres/samdino.html">this source</a> has clear instructions.
I would redo this part in my bare time.
<img src="./D6.jpg" alt="strandbeest" width="1000"/>
<img src="./D7.jpg" alt="strandbeest" width="1000"/>
Reference:
<a href="https://github.com/mattairtech/ArduinoCore-samd/tree/master/variants/Generic_D11C14A">D11C Spec</a>
<a href="http://fabacademy.org/2020/labs/leon/students/adrian-torres/samdino.html">bootloader the board</a>
###Group project
Testing with multimeter and oscilloscopes.
<a href="http://fab.cba.mit.edu/classes/MAS.863/Harvard/people/GabbyPerry/BoardTesting.html">Group project documentation</a>
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