<topbar style="display:none;"> <item><a href="../index.html">Home</a></item> <item><a href="../about_me/about.html">About</a></item> <item><a href="../week_x/index.html">Final Project</a></item> </topbar> <!-- This is a comment, it is ignored by the compiler/interpreter --> <style> h0 { font-family:; font-size: 30px; color: #414040; margin-top: 50px; margin-bottom: 6px; word-spacing: 5px; } a { color: #e479f1; } </style> ###Week3: Electronic Production /\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\ ###Idea This is the first time I make a circuit board from scratch. Before this, I have some arduino+ bread board experiences, yet, definitely not a pro. The assignment of this week is not for designing a circuit board, but producing a pre-designed board with its function. Below is the board <a href="http://academy.cba.mit.edu/classes/embedded_programming/D11C/hello.D11C.serial.5V.1.1">hello.D11C.serial.5V.1.1</a> that this course provides as an intro to the electronic world. <img src="./hello.D11C.serial.5V.1.1.png" alt="strandbeest" width="350"/><img src="./001.png" alt="strandbeest" width="350"/> <img src="./002.png" alt="strandbeest" width="350"/> ###Characterization of the SRM-20 Roland milling machine Characterization is important for every fabrication machine. In this group assignment, I mainly learned from my peer, Nicolo, who has prior experience on electronics. For the characterization, he used the usual example file, and compared the 1/64 milling end with some <a href="(https://www.amazon.com/SainSmart-Genmitsu-Engraving-Degree-Conical/dp/B07P99C2FH/ref=pd_ybh_a_3?_encoding=UTF8&psc=1&refRID=MD3Q4VJ24544254NBW4C">conical bits</a>, which are significantly cheaper and therefore interesting to test. The ones available in the lab have a clear plastic package that only reports "PCB Milling Bits R282", without any further spec. From top to bottom: the 1/32inch, the conical tip and the 1/64inch milling end <img src="./06.jpeg" alt="strandbeest" width="1000"/> This is the cheaper version milling end that can be bought from <a href="https://www.amazon.com/SainSmart-Genmitsu-Engraving-Degree-Conical/dp/B07P99C2FH/ref=pd_ybh_a_3?_encoding=UTF8&psc=1&refRID=MD3Q4VJ24544254NBW4C">Amazon</a>. <img src="./07.JPG" alt="strandbeest" width="1000"/> The top example was cut with the usual 1/64 inch, while the bottom one was cut using the conical bits. It seems that they both could cut the thinnest line, although for the conical ones they are not as thin as for the 1/64 inch. Both milled the copper between traces, but none did it for lines thinner than 0.020. I believe we should have changed some parameters in mods for the machine to engrave thin lines. All in all, this study shows that these other end mills could actually work well. <img src="./08.jpeg" alt="strandbeest" width="1000"/> ###Component shopping This shopping process is for sure the toughest part as an electronic beginner, since I don't know ANY of the terminology nor does their function. Gradually I learned each roll of the components,as well as the function of each serial on the traces. IC: stands for integrated circuits, while it can also be deems as voltage regulator.Basically, it can regulate the input voltage to from 5 to 3.3V in this case. J SWD: stands for socket, or header, as it shows on the box. It can output the data from this mini chip. C: stands for capacitor. R: stands for regulator. <img src="./01.jpeg" alt="strandbeest" width="1000"/> ###Milling I've failed many times from setting up the origin to getting the machine started. It was really because my carelessness not to count full 5 sec before I opened the machine's guard to manually adjust the Z axis to the PCB base plane. Another failing point was that the PCB was not cut through, with just some copper scratched off. Two possible reason of this failure: flatness of the PCB board or substrate and the z position of the milling end. We need to make sure the milling end is touch hard on the PCB board, as we likely lift the milling end up when tighten the knot. <img src="./02.JPG" alt="strandbeest" width="660"/> <img src="./11.JPG" alt="strandbeest" width="370"/> ###Sanding After milling, we want to clean up the dust that remains on the PCB board. First, I used vacuum to suck the dust, however it was not perfect. Then I asked Nathan and TA how to deal with the dust. Turns out, we can use fine sand paper to polish the board. It looks shining and clean after being sanded. <img src="./09.JPG" alt="strandbeest" width="385"/> <img src="./10.JPG" alt="strandbeest" width="350"/> ###Soldering Time for soldering! It's a tough task at the beginning since every thing is so small. I start to respect my husband who is doing semiconductor production in nano scale... After practices, I gradually get along with the soldering process. I will just put some solder on the trace before really attaching the components.Then, using the tweezers to position the components while melting the solder that's already there. <img src="./04.JPG" alt="strandbeest" width="370"/> <img src="./03.JPG" alt="strandbeest" width="370"/> ###Testing The way to test whether your board works is to burn a bootloader onto it -- after that, we'll be able to program the board over USB from e.g. Arduino IDE. But before that, we need a programmer to burn a bootloader, which we don't have yet for this week. We'll get to that point in a couple of weeks. For now Nathan demos us how to burn bootloaders just to see if boards are functional. <img src="./05.JPG" alt="strandbeest" width="370"/>