From 7eeb81d971b8de636cc9b43f1b6dd56c9ab17b13 Mon Sep 17 00:00:00 2001 From: Frederick Yin Date: Fri, 12 May 2023 09:36:17 +0800 Subject: projects/reflow-workshop: 2023-05-11 update --- docs/projects/img/reflow-workshop/flawed_qfn.jpg | Bin 0 -> 176817 bytes docs/projects/img/reflow-workshop/perfect_qfn.jpg | Bin 0 -> 76798 bytes docs/projects/img/reflow-workshop/poster.png | Bin 0 -> 2140360 bytes .../img/reflow-workshop/poster_printing.jpg | Bin 0 -> 200091 bytes .../img/reflow-workshop/reflow_workshop_title.png | Bin 0 -> 45677 bytes docs/projects/reflow-workshop.md | 130 +++++++++++++++++++++ 6 files changed, 130 insertions(+) create mode 100644 docs/projects/img/reflow-workshop/flawed_qfn.jpg create mode 100644 docs/projects/img/reflow-workshop/perfect_qfn.jpg create mode 100644 docs/projects/img/reflow-workshop/poster.png create mode 100644 docs/projects/img/reflow-workshop/poster_printing.jpg create mode 100644 docs/projects/img/reflow-workshop/reflow_workshop_title.png diff --git a/docs/projects/img/reflow-workshop/flawed_qfn.jpg b/docs/projects/img/reflow-workshop/flawed_qfn.jpg new file mode 100644 index 0000000..f017c1f Binary files /dev/null and b/docs/projects/img/reflow-workshop/flawed_qfn.jpg differ diff --git a/docs/projects/img/reflow-workshop/perfect_qfn.jpg b/docs/projects/img/reflow-workshop/perfect_qfn.jpg new file mode 100644 index 0000000..4190cbf Binary files /dev/null and b/docs/projects/img/reflow-workshop/perfect_qfn.jpg differ diff --git a/docs/projects/img/reflow-workshop/poster.png b/docs/projects/img/reflow-workshop/poster.png new file mode 100644 index 0000000..5496b3f Binary files /dev/null and b/docs/projects/img/reflow-workshop/poster.png differ diff --git a/docs/projects/img/reflow-workshop/poster_printing.jpg b/docs/projects/img/reflow-workshop/poster_printing.jpg new file mode 100644 index 0000000..897c732 Binary files /dev/null and b/docs/projects/img/reflow-workshop/poster_printing.jpg differ diff --git a/docs/projects/img/reflow-workshop/reflow_workshop_title.png b/docs/projects/img/reflow-workshop/reflow_workshop_title.png new file mode 100644 index 0000000..664255b Binary files /dev/null and b/docs/projects/img/reflow-workshop/reflow_workshop_title.png differ diff --git a/docs/projects/reflow-workshop.md b/docs/projects/reflow-workshop.md index 4e35c85..e373388 100644 --- a/docs/projects/reflow-workshop.md +++ b/docs/projects/reflow-workshop.md @@ -226,6 +226,16 @@ isopropyl alcohol, but "industrial alcohol" on the marketplace refers to methanol. The customer service kindly suggests I look for "industrial ethanol". I ordered 500 mL. +## 2023-04-02, Sunday + +Today I made what I consider one of my best designs with Inkscape. + +!["TECHJI REFLOW WORKSHOP", but the "O" in "REFLOW" is shaped like an IC +chip and there's a via next to the +"W"](img/reflow-workshop/reflow_workshop_title.png) + +▲ The font is Orbitron. + ## 2023-04-03, Monday The Japanspachtel are here. I headed to the hackerspace and did a partial @@ -431,3 +441,123 @@ Both the magnifying glasses and spray bottles are here. ## 2023-04-15, Saturday I got the 20 PCBs and the invoice for everything I ordered from JDB. + +## 2023-04-26, Wednesday + +After a week of final exams, I took a few days off to relax, before +rediscovering the existence of reflow workshop. + +It's spring break right now and I'm at home. At this point everything +seemed ready, but an inventory check reported a lack of cell batteries and +holders. So I ordered a bunch more. + +## 2023-04-28, Friday + +I went back to uni to pick up the package. I also went to two concerts +where I caught a guitar pick. + +## 2023-05-06, Saturday + +I discussed workshop arrangements with my colleagues at TechJI. It will be +held twice on both evenings this weekend. + +## 2023-05-07, Sunday + +Behold, the final poster design: + +![From top to bottom: anime girls pic, "TECHJI REFLOW WORKSHOP", PCB +renderings, 5/13-14 18:00 唐君远, and credit for the +illustration](img/reflow-workshop/poster.png) + +▲ Despite the visual effect, most of the graphics is not my own. + +## 2023-05-08, Monday + +I drafted the promotional article to be published on WeChat. + +## 2023-05-10, Wednesday + +### Afternoon + +The article is published, but WeChat decided that hyperlinks are not +allowed. Among them is the survey we use to register participants. +Sabotaged by WeChat's pointless restrictions. + +I received messages asking for the link, but I can't edit the article +(thanks WeChat), nor can I post it in the comments without approval (many +fucking thanks WeChat). I ended up urgent pinging the admin, who +thankfully made it public real fast. + +The moment link went public applications blew up. In two hours we had 32 +applicants. We can seat at most 19, because we only have so many ATtiny's +left. This means I'll have to send rejection letters to so many people. +I've always hated rejection letters. Now I've become what I swore to +destroy. + +Conclusion: Tencent is a horrible asshole whose sole purpose is to destroy +the open internet. + +### Evening + +I made a horrible mistake. I made applicants fill in their cell number, +and stated that I will contact them via SMS or WeChat. HUGE mistake. I had +to manually copy the numbers to my phone. Should have asked for email +instead. + +## 2023-05-11, Thursday + +I went to print the poster on an A2 sheet of paper. It's pretty! + +![Poster in a giant printer](img/reflow-workshop/poster_printing.jpg) + +▲ The exposure is _just_ long enough to blur the print head, which I think +makes the photo way more dynamic + +I cycled to the hackerspace to hang it up. It's much smaller than all the +other posters, but it's hands down the prettiest. + +After that we had an internal training session within TechJI. The purpose +is to familiarize ourselves (including me, because the last time I did +this was one month ago). We started with an overview, then we smeared +solder paste. Everyone had their own technique. The common trend is too +much paste, and/or going over one place too many times. Everyone had to +rework at least once, because that is essential knowledge for the +workshop. + +Who could apply paste the best? We have a winner! + +![Paste in the right places on the QFN +footprint](img/reflow-workshop/perfect_qfn.jpg) + +▲ This is a sign that they are better at it than I am + +Up next we had pick-and-place. Sadly we can't offer a complete kit to +everyone because we need to leave enough for the 19 people. Two of us were +actually among the 19, so we decided to make two prototypes. + +I demonstrated C1 and C2 (the two 0805 caps), and made a few comments on +the polarity of the diodes, pins of the QFN, and the 0402 region where you +make a recognizable pattern so you know which board is yours on the +hotplate. + +No one had any trouble. I inspected the result which is shockingly great, +then turned on the heat. + +One of them is observed to have two shorts on RN2, and the other is +flawless. However, when we put a battery in it, the RGB LED (D6) doesn't +turn on. Why not? It turns out D6 was upside down. It is indeed very +subtle, and even I failed to catch that before heating. Then I noticed the +same problem on the other board. With a soldering iron I manually fixed +them. + +It's time to test our products. Weirdly, one works, but the other is +really bad-tempered for some reason. Whenever you remove your finger from +the battery, it hisses nonstop. I would advise it to see a therapist. + +I asked Kliment what could be the reason, and he suggested it was either +a short on the MCU or the resistor packs, or a shoddy battery holder, +because the kitten hisses when reset. + +To my disappointment I only ordered 100 LEDs, which is _barely_ enough. +And to an electronic engineer _barely_ enough is not enough. We have to +keep a redundancy, so I ordered 200 more. -- cgit v1.2.3