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diff --git a/docs/projects/img/reflow-workshop/electronic_cat.jpg b/docs/projects/img/reflow-workshop/electronic_cat.jpg Binary files differnew file mode 100644 index 0000000..dfdfa57 --- /dev/null +++ b/docs/projects/img/reflow-workshop/electronic_cat.jpg diff --git a/docs/projects/img/reflow-workshop/empty_tjy.jpg b/docs/projects/img/reflow-workshop/empty_tjy.jpg Binary files differnew file mode 100644 index 0000000..5383300 --- /dev/null +++ b/docs/projects/img/reflow-workshop/empty_tjy.jpg diff --git a/docs/projects/img/reflow-workshop/qfn32_socket.jpg b/docs/projects/img/reflow-workshop/qfn32_socket.jpg Binary files differnew file mode 100644 index 0000000..1d4fd85 --- /dev/null +++ b/docs/projects/img/reflow-workshop/qfn32_socket.jpg diff --git a/docs/projects/index.md b/docs/projects/index.md index eda291d..ddbf0cb 100644 --- a/docs/projects/index.md +++ b/docs/projects/index.md @@ -8,6 +8,10 @@ MkDocs). But the few that do, are here. Projects below are sorted reverse chronologically (most recent first). +## [Reflow Workshop: A Journal](reflow-workshop) + +I'm working on it! + ## [bash workshop](bash-workshop)  diff --git a/docs/projects/reflow-workshop.md b/docs/projects/reflow-workshop.md new file mode 100644 index 0000000..ea2c638 --- /dev/null +++ b/docs/projects/reflow-workshop.md @@ -0,0 +1,128 @@ +# Reflow Workshop: A Journal + +Status: updating + +## 2023-03-15, Wednesday + +Today I took a group interview for assistants of a new hackerspace. Five +students were present, in a room with Mr. Xiao, the manager. + +My prior work experience bought me some credibility, and I shared with +Xiao my frustration not being able to properly do electronic engineering +for lack of resources. + +We then took a walk in the empty hackerspace. The proper name is actually +Tang Junyuan Student Innovation and Entrepreneurship Center, but I prefer +hackerspace. + + + +▲ This is only half of the hackerspace. + +We had a heck of a time discussing what this space is potential of. +Four-wheelers. LaTeX and vim workshop up the stairs. And of course +— reflow soldering. + +Reflow soldering is on my [list of life goals](../random/life_goals/), but +it's in my dream since 2019. At that time I was a nobody in high school. +All I could solder was through-holes. Kliment, my IRC friend (though we've +met IRL once) kindly mailed me one of his works: [an electronic +kitten](https://github.com/kliment/catws). It is 5cm×5cm. + + + +▲ It purrs when you stroke it right; otherwise, it hisses. + +## 2023-03-16, Thursday + +So I revealed my plans to Kliment, who was very supportive as usual. He +forwarded me an email listing the things I need. + +One crucial thing is that I have to program the <abbr +title="microcontroller unit">MCU</abbr> before soldering, so I need +a <abbr title="Quad-Flat No-leads with 32 pads">QFN32</abbr> test socket. +Kliment estimated it to cost 800 RMB, but in China it seems to only be +~200. I bought one for 180. + +## 2023-03-17, Friday + +Just ordered the two parts from LCSC with specific numbers: Murata +PKMCS0909E4000-R1 and Meihua MHS110FRGBCT. LCSC gave me a 20 RMB coupon. + +After that I went to look for the MCUs (ATtiny88-MU) and found them in +a random Taobao store that sells them at 7 RMB apiece. I think I might +need other chips later, so I also added some ATtiny48 and ATmega328PB to +my shopping cart. I asked customer service if they got any in stock. They +said I could just place my order, so I did. + +Then I went to hunt for the PCB and stencils. Kliment forewarned me that +factories use only one stencil per assembly line, so my use case is +extremely rare. I will have to consult the manufacturer for a quote. + +## 2023-03-19, Sunday + +Talked to the sales rep of JDBPCB, they were confused for a good minute, +then realized what I was asking for. They told me to just place my order. +They claim they had seen this kind of thing before. Kliment suggests it +might have been [Honza Mrazek](https://honzamrazek.cz/). + +Sent <abbr title="basically a zip file of everything the factory needs to +produce PCBs and stencils">Gerbers</abbr> to them, along with my requests +in the notes. They PCBs are approved. + +## 2023-03-20, Monday + +I received the piezo speaker and RGB LEDs from LCSC today. + +To my surprise JDB approved my stencil request, and priced it at an +unexpectedly low 80 RMB. + +Later the customer service approached me to confirm once again that +I wanted 10 copies of the same stencil. Upon hearing yes, they revealed +that the 80 RMB was actually the price for *one* stencil, but for me they +could do 216 RMB for 10, tax included, with the implication that I do not +do this kind of shit to them again. They fear me. + +Kliment helped shave off 46 RMB off my budget. I was looking for +a hotplate which he said will not cost more than 80 RMB. When I told him +best I could find is 135, he said I was looking for the wrong thing; what +I need is not a hotplate advertised for solder work, but a consumer grade +for heating food and beakers. I changed the keyword and found one at 89. + +## 2023-03-21, Tuesday + +Cell batteries, holders, and the QFN32 socket have arrived. + + + +▲ \*Kneels on floor\* \*Unlids socket\* \*Presents brand new ATtiny88-MU\* +Will you marry me? + +The socket is a delicate piece of hardware. You would place the MCU in +a 5mm×5mm slot where two adjacent pins are 0.5 mm apart, and access them +from a <abbr title="Dual In-line Package">DIP</abbr> interface where that +distance (also known as the lead pitch) is 2.54 mm. + +The microcontrollers on the other hand haven't even begun shipping yet. +I asked them what's wrong, and their answer was: "we don't have them." + +…Then don't sell them? + +I then asked when they will be back on stock. They read my messages but +remained silent. Chances are they will never ship, says Kliment. This is +just a scam on a chain of fake distributors. The evening they finally gave +in, offering a refund. + +At the same time I'm looking for more trustworthy vendors. Kliment +referred me to Winsource. Although a Shenzhen company, they don't seem to +ship to China under that brand. So I reverse engineered a bit to find that +its Chinese trademark is 聚源鑫. Small company, not super well-known, not +even a store on Taobao. I'll talk to them in working hours tomorrow. + +I am currently inside an episode of self-doubt. What if I fail to learn +reflow myself? Even if I can barely manage, what qualification do I have +to teach other people? Perhaps I should have picked my battles and went +for a simple SMD hand soldering workshop instead. That's much much easier, +and I have done this three times. |
