This week, I learned how to use Spice, Eagle, and how to design circuits. I was mainly focused on learning these tools as opposed to designing something original. My design is based on the "hello" board design that was shown in class.

This is the final device after stuffing the board.

This shows the final design in Eagle.

I brought the png files into Adobe Illustrator to make sure they were the right size. I did not have to invert the colors to make sure the traces were white since I exported them from Eagle as monochrome. When exporting from Eagle, I had to make sure the resolution was high (I picked 2,000dpi). At first I left it at 300dpi and the traces were all pixelated.

These are the pin-outs for the the chip I used. The Atmel AttTiny44.

I ran into lots of snags when I was using Eagle. One problem is that I could not save since the permissions in Mac OS were set wrong. I navigated (in finder) to the right folder and set the permissions to read-write.

My design was based on this png of the "hello.ftdi" that was provided on the HTMaA website.

1. Problems creating a ground in Eagle. Solution: you can find that in the "supply" library.. can be downloaded here
2. I had trouble finding the right LED since some were not labelled in the drawers in the lab, and the descriptions in the provided library were sparse. In the end, I chose the one that looked the most like the RGB LED I found in the lab. I think LEDRGBOLD (in the eagle library) was the correct one.
3. Trouble cleaning up the air-lines in Eagle: I used the "ratsnest". Bummer I only found this once I was nearly finished!
4. How to change the "minimum distance" when moving components around in Eagle: as it turns out, everything is based on a grid. The grid line separation distance can be set by clicking on the grid button in the upper left corner.
5. Trouble changing the "blue area": so it turns out that the blue area is actually just a rectangle that has been automatically drawn in the "background layer". You can access layers just like any other program that uses layers like Adobe Photoshop. Just click on the layers button and scroll down. Once you're there, use the "move" button and hold down control to manipulate. The same thing is true if you want things to snap, exactly, to the grid.
6. To create a PNG, all I had to do was turn off most of the layers and save as a monochrome PNG with a decent resolution (I used 2,000dpi).
7. I had a bit of trouble with my row of 6 pins (PTDI) resting on a trace. It would have been easier if the representative CAD file for this part showed these lines. I didn't find them in the library, but they are probably there somewhere. If not, I could have measured them and drawn them in. In hindsight, I wish I had done this, because I ended up having to resolder this component further over to avoid the trace.
8. To change the trace width I clicked the wrench icon and scrolled down to "width".
9. I used Adobe Illustrator to make sure the PNGs were the right size. I also placed the actual physical components on the screen once the image had been scaled to 1:1. This gave me the confidence that everything was ready to be milled and stuffed.
10. I had one bad trace where the gaps between were not large enough, but I used a razor blade to carve away the copper.