Redraw the echo hello-world board
- add (at least) a button and LED (with current-limiting resistor)
- check the design rules, and make it
- extra credit: simulate its operation
Since I have zero experience of circuitboard design, so I followed this assignment note of fab 2014 to do my work.
1. Import lib
Eagle provides enormous library of components, but for the purpose of this assignment, it will be better and easier to work with the library already provided by the academy.
After opening Eagle, on the top toolbar there is a button "Use library", click it and select the libraries you've downloaded a while ago.
2. Add components
The next step is to add components into the schematic canvas. The first component you are going to place is microcontroller ATtiny44. Choose ATTINY44-SSU from the FAB library and click ok to place it on your schematics.
After placing one component you can press "esc" and go back to "add panel". Add other components:
3. Sketch the schematic
After adding all the components, it's time for some wiring, naming and labeling. You'll use these commands:
You should label all the pins right. And the net should not overlap the pin. It's easy to mess up. So doblecheck everything. Here is my schematic:
4. Generate board
Click "Generate/Switch to board" button next to the lib button.
It'll take you to board view. All the commponents are ready to re-arrange.
Use move and rotate commands to arrange the board. You might need to adjust grid setting for finer position control.
All components seem to be at the right place. Use "Ratsnest" command to clear some connetions.
Then I tried Autorouter, but the result was not desirable。
5. Route manually
Follow the yellow traces, I route the board manually. These's a tip: you can right click to change line modes when you come to a 90 degree turning point.
After finishing routing, you can hide layers except "top" , then you can see the nice traces of your board:
Export your image as a PNG selecting only the top layer of your board. You'll only get the traces of it. Don't forget to check the Monochrome checkbox.
Next, export "Dimension" layer for the board.
It's time for milling. Upload eagle export to fab modules. I set the dpi to 1500 px and the route result seems ok.
The traces, not bad.
And the finish board:
Now, the finally step, assembling.
Picking out all the components can be quite a painstaking job. I draw a sketch to assure everything is ready.
I like doing soldering, although I still have some trouble with those tiny components :)