WEEK 06

Exercise 6

Redesign, make and program the Hello World Board

The exercise of this week assignment has been quite interesting and a bit complex for me. Since I am not so familiar with electronic design, I did everything step by step. The most important and helpful support is the Hello World-board pictures and all the links which can be downloaded here.

This image has been the most important starting point for me.





My approach started from the basics. I tried to understand the function of each component, making a research on them, in order to figure out how to design the board in an efficient way. To make things more clear, I have created a chart, expecially when I would start to add all the components in a new file of Autodesk Eagle software.





I opened a new file from Autodesk Eagle, starting from the schematic. Before starting to add the components, it has been necessary to install the library FAB, since almost all the components we need are in this library, which can be downloaded from Atmel website, here. After downloading, I simply tried to drag and drop the file to the libraries list on Eagle. Unfortunately, it seems not working.



Then, I cliked on "USE LIBRARY" command and selected the fab library. Loading has been successful.



I started to add the component I have arranged within the chart. The command is Edit/Add+. Once a window will open, it is necessary to look for fab library, choose the component and add it into the schematic space. After that, it is recommended to click some neutral command to quit adding components.



Next step was to assign to each pin a name, which will connect the other pins from other components. I used "net" and "label" command to prolong each pin and to name it. I was not able to find a quicker solution to assign the right pins together. This process requires a bit of time and patience. I preferred to not include the led and the switch at the beginning, to keep everything more clear. I would add it after few steps.



To create the board, I used the command "Generate/switch to board"



After having the components with all the connections, I tryed to change the components position in order to achieve a smart configuration, using move and rotate command.



Then I used "autorouter" command (tools/autorouter) to create the traces. A window will pop-up for settings: since the board requires just one layer circuit, I have set TOP= *, and BOTTOM=N/A.

After that, I moved and rotate some components and I used the "Rip up" and "Enroute" command for traces.





Now it is time to add the switch and led, with the related resistance. Since I didn't know which pin of attiny to use, I did some research and read about the attiny pins here. I used again the autorouter command as before. I have noticed that again some connections are not perfect and the traces can be optimized. As a matter of fact, using "Rip up" and "Enroute" command, I tryed to improve the traces and connections between pads.



Once traces were done, I opened the layer windows and create a new one with the name "CUT". I used the command "line" to create a rectangule and then applied some fillet to corners, in order to have a kind of old play station memory card shape.
I know, I am a nostalgic boy.



I thought it was a nice idea to cut some circles to eventually fix the board somewhere. I also switched off all other layers, keeping only TOP and CUT layers active, since they are the only useful layers for milling and cutting png image.


I was ready to export the png images in roder to process them with fabModules and get the .rml files for milling and cutting. Export/image is the command I used. I set 1000 dpi to get a good image quality and switched to monochrome, since we just need a B/W image.





I added some text in Photoshop and fixed some traces imperfections. After loading and processing the png images with fabModules, I got these three .rml files.





Unfortunately, after milling I realized that there are issues, such as not good milling between some pads and traces. I decided to improve the board from Eagle, also adding a resistance connected to the switch.




Here are the HelloWorld board last version pictures, with .png files for milling and cutting






Once ready I connected the board to my Macbook, but there was some issue, inviting me to "the Double Check Connection". After checking all the circuit and paths, which actually worked, I checked again with my tutor the sketch on Eagle. We realized that I did a silly mistake by connecting some pins of the ATTINY. So, I fixed the issue and milled another board. After solding all the components I plugged it into the Macbook. The board was finally recognized by the computer. On Week8 page, I run some programs using Arduino IDE.

DOWNLOAD FILES