For this week's assignment I spend a significant amount of time refreshing my knowledge of electronics as well as familiarizing myself with the Eagle software. I found the Sparkfun tutorials particularly helpful for refreshing my knowledge on the topic. You can find these tutorials here:https://learn.sparkfun.com/tutorials/what-is-electricity. I also suggest completing the additional readings they point to around Electric Power and Board Making in Eagle. During my quest to learn I also stumbled upon this fabacademy tutorial:http://academy.kaziunas.com/tutorials/electronics_design_eagle.php#step2. Although many of the image links were broken, this tutorial was still the msot helpful and clear in helping me with this week's assignment. The author clearly walks you through the steps of downloading Eagle and importing the fab library. I also imported the SparkFun library. Once on Eagle it took me some time to find the correct parts. It took me some time to learn some of the functions in Eagle like how to label, name, and net traces so they were correctly aligned.
From the schematic the board layout process what a bit daunting. I learned a few useful tips when organizing. First, the fact of organizing the board pointed out several mistakes I made in the schematic. For one I selected the wrong ground icon as a result I had additional pads visible for the board. Additionally, by typing in commands like "show gnd" I was able to see the path for ground to double check my connections. I noticed at one point that some of my ground segements looked off and this was because they were not properly connected in the schematic. Other tricks, I used the manual route tool to create my traces. I also became very familiar with the rip route tool as well. It was particularly tricky to figure out how to get three traces underneath attiny44 that were needed for the board design. At one point I tried to see what the autotroute option would show, but it was not too helpful. I also used the DRC button - design rules check - to make sure the traces had enough clearane. Another test was to use the ratsnest command do see if the board is disorganized. If it is OK, the command will read "Nothing to do."
The first time I went to mill the board it was a disaster. I didn't check to make sure the bit was in good shape and as a result I got the very poor result you see to the left. Another issue I ran into was with the dpi resolution. Initally when I exported from Eagle I put my traces into Gimp to get an inverted image and to draw the dimensions. However, when I did this the resoltuions of the files got distorted when imported in the fab modules. Thanks to help from Albert I found out how I could get the dimensions layer to be exported from Eagle. I then decided to bring the exported image files directly into the fab modules and use the image inverting option. I also found it imported to check the bits before I used them to check for health and quality. When I replaced the 1/64 it cut the traces beautifully. The board took about 10 minutes to mill.
Who would have thought that a few weeks ago I would be saying that stuffing the board was my favorite part??? I can't believe how much more relaxing and enjoyable soldering was this time around. I had some challenges finding the parts, especially finding the right resonator. The resonator also posed a challenge when soldering as it doesn't have any protruding pins to solder onto the pad. Ultimately I settled on wetting some solder on the three sections under the resonator. I then carefully rested the resonator on top and head the pads so that the solder flowed underneath. I then added more solder onto the ends of the component.