electronics design
I used Eagle to do my schematic and board design. It is not the most usable UI but was fine once I got used to its quirks. The fab library was very helpful for finding the right components, and anything missing from there I was able to find in the SparkFun library, which I also downloaded. I know very little about electronics, so making the schematic was a bit confusing. But, with some help from classmates and people's pages from last year, I think I managed fine.

Laying out the board was a bit intimidating at first. I tried autoroute, but it would only come up with 2 layer solutions even when I put a strong penalty in the preferences against doing that. I ended up laying everything out by hand instead, and I tried to look at boards from last year to help me figure out how to do that without having to use any 0 ohm resistors to do jumps. It took me awhile to finally come up with a layout that worked, but I was worried about the three traces going underneath the Attiny being too close together.


I didn't make my pngs with photoshop like we did in section. I just exported images from Eagle and used those directly. To cut out my board, I made a rectangle in the "Dimension" layer, and that worked fine on the Modela.

Cut out:

Milling my board went pretty smoothly, but I did have some issues with those three traces being so close together.

If I had clicked on "view path" in fab modules to look at the path up close, I would have seen that it wasn't going to cut between those traces. On my second try, I reduced the diameter from .4 to .35. This time when I clicked on "view path", the traces looked good, and it turned out perfectly when I milled it.

For me, the secret to soldering is wearing my glasses (which I did not do last time!). Actually being able to see what I'm doing made the entire process much easier, and I finished my board without any problems! I want to try to program my board soon to see if I did this correctly, but, even if I didn't, I think I know enough to be able to fix it and try again. I worried that my solution would be messy and hard to make, but I am happy with the result!