W06 - Electronics Design¶
1. Weekly Assignments ( -> what I did this week )¶
- Group assignment
Use the test equipment in your lab to observe the operation of a microcontroller circuit board
( -> I tested the Digital Oscilloscope and Digital MultiMeter with the group members. )
- Individual assignment
Redraw the echo hello-world board, add (at least) a button and LED (with current-limiting resistor), check the design rules, make it, test it.
Extra credits: Simulate its operation. Render it.
( -> I made hello-world board adding a button and a LED with current-limiting resistor. Then, I checked the functionality. It worked fine. )
( -> my answers )¶
Shown your process using words/images/screenshots ( -> yes )
Explained problems and how you fixed them, including how you worked with design rules for milling (DRC in EagleCad and KiCad) ( -> yes )
Included original design files (Eagle, KiCad, Inkscape, .cad - whatever) ( -> yes )
2. Group Assignment Link¶
I summarized how to use Digital Oscillosope ( Tektronix TBS 1052B ).
3. Works, steps and some details¶
1) Redraw the echo-world board on EAGLE CAD¶
I decided to add one LED and one button.
|selected “eagle_fab_lbr”||“Use none” for “Managed Libraries”|
|add parts||selected ATTiny44|
|“design Rules” setting||“Grid” setting|
|line width setting||ERC error|
|ERC error , and then, fixed one by one||component layout on PCB|
|design Rules||tried “Autoruler”
jumper on the backside of PCB is shown with green color
|“Autoruler” setting||“Autoruler” setting ( this was used )|
|After thickened GND lines manually, DRC error ( airwire ) were found, but not a big problem||blue line shows the jumper on the backside of PCB, so tried to set the holes and via|
|relocated the route of jumper so that it can be soldered firmly.||hole diameter|
|“via” ( to support jumper ) property|
2) Milling PCB and Stuffing¶
CNC parmeters for circuit pattern
tool diameter (in) ; 0.0156 (1/64)
cut depth (in) ; 0.004
max depth (in) ; 0.004
offset number ; 4
milling speed ; 4 mm/s
|mods to create the circuit pattern ( “dpi” needed to be changed from 800 to 1600, to fit the proper scale. This might be depending on the MacBook Retina display. )|
CNC parmeters for holes and outline
tool diameter (in) ; 0.0312 (1/32)
cut depth (in) ; 0.024
max depth (in) ; 0.072
offset number ; 1
milling speed ; 4 mm/s
|mods to create the holes ( also, “dpi” 800 -> 1600 )|
|pattern.png||jumper holes ( milling.png )|
|milling the plate|
|unnecessary portions were removed|
|after stuffing the components
( added the black mark for GND )
3) Functional Check¶
A. echo program
I downloaded “hello.ftdi.44.echo.c” from fab academy site, and implemented using the commands below, referring the site below.
make -f hello.ftdi.44.echo.c.make
make -f hello.ftdi.44.echo.c.make program-usbtiny-fuses
make -f hello.ftdi.44.echo.c.make program-usbtiny
|selected “Serial Monitor” in Arduino IDE||port setting|
|115200 baud rate||It worked fine! ( but put PCB on the aluminum body of MacBook might “not” be a good idea )|
|LED on-off switching test|
B. LED on-off switching program
I downloaded and implemented the program file “LED2.c” from the site below.
And, it worked fine.
4. Important Learning Outcome¶
1) GND design on PCB¶
In order to avoid the possible problems regarding the ground lines on PCB, I decided to use jumper on the backside of PCB, also manually thickened the GND lines.
The PCB worked fine, although whether it was because of the above decision or not, I think this is a safer way especially for more complicated PCB design.
2) EAGLE “Autoruler”¶
This function helped me a lot to save time. I’ll explore this function more precisely.
5. Links to Files and Code¶
EAGLE CAD files :
.png files :
.rml files :
“echo hello” files :