Electronics Design

Assignments

Redraw the echo hello-world board, add (at least) a button and LED (with current-limiting resistor), check the design rules, make it (if you have time this week, test it). (Individual Project)

Optional: Simulate its operation. Measure its operation.

I drew a board with a kitten head outline, it is my first time to make customize outline. It is interesting to draw the ouline with Inkscape. And for this board,I can't find the smaller soldering head, and I was in a rush to solder, the joint was so ugly, I'll improve next time.

Redrawing the Echo Hello-World board

I used Autodesk Eagle 8.7.1 to redraw the Schematic and Board Layout of Echo Hello-World board.

Component library: fab.lbr

First of all, download the fab.lbr -component library by right-clicking 'Save the link' and adding the library to Eagle installation folder (C:\EAGLE 8.7.1\lbr).

Then, open the Eagle and navigate to Libraries > lbr where you can see the new library marked with the grey small dot. Activate the library by right-clicking it and selecting "Use".

Draw the Schematic

Next, I created a new project by navigating File > New > Project. Then, I created a new schematic by right-clicking the New Project > New > Schematic. After that, I added components to Schematic.

Pin header 2x3 // "AVRISPSMD (2X03SMD)"

FTDI header 1x6 // "FTDI-SMD-HEADER"

Capacitor // "CAP-US1206FAB (C1206FAB)"

Resonator

Resistor // RES-US > "RES-US1206FAB (R1206FAB)"

Besides these ones, I addd a button and a LED,

Button // "6MM_SWITCH6MM_SWITCH (OMRON SWITHC)"

Red LED // "LEDFAB1206 (LED1206FAB)"

From the supply1 -library I added:

GND // SUPPLY SYMBOL

VCC // SUPPLY SYMBOL

Then I read ATtiny44A datasheet to figure out the pin numbers of the micocontroller.

With the help of my tutor Yufei Ma ,I drew the schematic as below.

I finished the PCB and output this PCB as png format in 2000 dpi.

Check the design rules

I tried to follow the design rules of drawing a PCB board. Starting from the settings, I did as follows:

Selecting the DRC (Design Rule Check) settings from the toolbar, I defined new values:

Clearance // set all the 'Different Signals' and 'Same Signal' to be 16mil
Distance // set Drill/Hole to be 16mil
Sizes // set Minimum Widht to be 16mil, too
Supply -tab // set 'Thermal isolation' to be 10mil, and 'Apply'

And then also run ERC option.

When the board layout is finished, select Layers and leave only the Top layer visible. Otherwise there will be some values on the png picture.

And then created the .rml files of traces in Fabmodules.org by importing the png file.

And for the shape, I wanted to make a cat shape board, so I insert the board traces to inkscape and draw a cat outline for the board.And then I made the rml file and mill it.