# Electronics Design

1. Assignment

1.1 Group project:use the test equipment in your lab to observe the operation of a microcontroller circuit board 1.2. Individual project:

• redraw the 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
• extra credit: render it

2.ECAD software:

• Download the software: EAGLE(Easily Applicable Graphical Layout Editor)https://www.autodesk.com/products/eagle/overview download page
• I should sign in Autodesk account to get it, this time I use free version(8.5.0).
• We can find compare EAGLE Premium vs. EAGLE Standard vs. EAGLE Free in the following page https://www.autodesk.com/compare/eagle-vs-eagle-premium
• Install the software according to the guide

3. Start

3.1. Creat a new project

(File→New→Project), we build one call "hellofab",we can do our work in this folder

EPF file link our schematic to PCB board and also contain some parameter for this project

3.2.Make a schematic　

Schematics are our map to designing, building, and troubleshooting circuits.
There are many symbols as following:

3.3. Library/Use

EAGLE comes with huge component library, however to find the desired part in this library is really difficult for beginners. Generally we need resistors, capacitors, voltage regulators, pin headers,connectors, etc when designing any electronic PCB. This is an amazing resource! Instead of using the hundreds of default libraries, we use the FAB Libraries, which are filtered down to only include the parts that we’ve used in designs ourselves. In addition we can find many library in the official link

4. Redraw hello-world board

4.1 .basic introduce

I learn eagle basic practice according to the following picture

4.2. Add components

I use"Add" button in "Command buttons" We can find the active libraries in a new window. According to the above drawing,I need to add some components:Resistor, Capacitor, Resonator, Chip, Pin header,etc

There are two method to find the components:

• We can find the components in library manage according to library logic,For example ATTINY44-SSU(fab-ATTINY44-ATTINY44-SSU)
• We can directly searchATTINY44-SSU if we now the keyword of components

In some method, I add another components

4.3 Position of components

Use move rotatebutton to update the position of component to make it in the same as reality logic Position the component ,we can compare the different with the last picture

4.4 Line

Use line button to create the trace between the components, and then check if it connect(we can move the component ,if the line change according to moving ,it is OK ,or we need to re connect the components use linebutton)

4.5 label, net,name

If we direct use line to connect the component, it is complex and easy to have problem. So we will use label ,net ,name to optimize the schematic

After optimize , the result is the following

5. Board

5.1 Creat basic board

After I check with the schematic to confirm there is no mistake. Then we can go to the next stepI use the command Generate/Switch to make the board. We can find all components on the board.But there is no rule in the components' location now. And we need to add rule one by one.

5.2 Create a DRC:Design Rules Check

The location is in Tool -DRC According to Instructor's guide and experience, I set the parameter as the following:

5.3Move and rotate

as done before in the schematic, we need to place de different components on the board. In the Sparkfun tutorial that I followed they light up some basic rules to have in mind when arranging the components. These rules are: A. Don’t overlap parts. B. Minimize intersecting airwires: when you are moving the components you have to see how the wires are moving with them. C. Part placement requirements: Some parts may require special consideration during placement. D. Tighter placement means a smaller and cheaper board, but it also makes routing harder. This point get from victoria-peredorobinson After optimize the components' position and degree ,the finial result is the following:

5.4 Output data

Output png:File-Export- Image and then define some parameter according to the following figuare I use Photoshop to change the size, then invert the dawing,and make the 'trace' and 'outline' In fabmodules,I define some parameter ,similar in Electric production.

6. Make it

This reference "Electric production"

• Load board;
• Load cutter(1/64'') and set the xyz origin position;
• Load trace file
• Cutting the trace and clean it
• Load cutter(1/32'') and set the xyz origin position;
• Load outline file
• Cutting the outline and clean it
• Unload the board;
• Use sandpaper and alcohol to polish the PCB board;
• Solder the components to the board according to eagle design and BOM