From a3d4309cecee9e826cfdeaaf0809c5acc1ed7173 Mon Sep 17 00:00:00 2001 From: Frederick Yin Date: Sat, 23 Mar 2024 19:11:28 -0400 Subject: New post: projects/idkhow-pcb --- docs/projects/idkhow-pcb.md | 80 +++++++++++++++++++++++++++++ docs/projects/img/idkhow-pcb/bantam.jpg | Bin 0 -> 338891 bytes docs/projects/img/idkhow-pcb/kicad_pcb.png | Bin 0 -> 93357 bytes docs/projects/img/idkhow-pcb/product.jpg | Bin 0 -> 308565 bytes docs/projects/img/idkhow-pcb/stack.jpg | Bin 0 -> 151479 bytes docs/projects/index.md | 6 +++ 6 files changed, 86 insertions(+) create mode 100644 docs/projects/idkhow-pcb.md create mode 100644 docs/projects/img/idkhow-pcb/bantam.jpg create mode 100644 docs/projects/img/idkhow-pcb/kicad_pcb.png create mode 100644 docs/projects/img/idkhow-pcb/product.jpg create mode 100644 docs/projects/img/idkhow-pcb/stack.jpg diff --git a/docs/projects/idkhow-pcb.md b/docs/projects/idkhow-pcb.md new file mode 100644 index 0000000..bdf6137 --- /dev/null +++ b/docs/projects/idkhow-pcb.md @@ -0,0 +1,80 @@ +# I DONT KNOW HOW BUT I MADE A PCB + +2024-03-23 + +Last December I made a bold move to buy a ticket to iDKHOW's show in +Detroit. The show is on April 5th. + +I've heard of fans giving out handmade souvenirs on shows like this. In my +mind I have a PCB with the band logo on it. The logo happens to be super +regular shapes like lines and arcs. As long as I don't do it for profit, +I'm fine. So I imagine I'd be at the show just handing them out to people. + +## Step 0: What do I make and how? + +First idea: blinking LEDs like my previous PCB, [Blobcat](blobcat-pcb.md). + +Too many parts, too much soldering. No time for that when I've got 18 +credits of courses. + +Second idea: a coil that harvests power from your phone's NFC and light an +LED. + +Much less soldering but physics is too hard. I can't even prove it's +feasible. + +Third idea: just a logo and nothing else. + +Really easy to design but a waste of money if I pay a factory. But there's +another option. + +There's a Bantam machine at my uni that any student can use as long as +they passed a quiz. The Bantam is basically a computerized milling +machine. Instead of dissolving copper with chemicals like they do in +factories, it mechanically etches off copper with a drill bit. + +A common drill bit is 1/32 inch, or about 0.8 mm. This means I can't do +fine traces. Not a problem. + +## Step 1: Design PCB + +I created a PCB with KiCad with only two useful layers: + +- F.Cu (front copper, where my design goes) +- Edge.Cuts (board outline and holes) + +To minimize milling time, I need to maximize copper and minimize etching. +So I fiddled around a bit and found such a design that looks ok: + +![KiCad PCB design measuring 36×26 mm with +a hole](img/idkhow-pcb/kicad_pcb.png) + +The red curves and pale red solid fill are copper and between them is +where the drill bit goes. + +## Step 2: Use the Bantam + +On 2024-03-20 at 18:00, I checked in at the machine shop. My friend guided +me through the process and gave me his drill bit. The drill bit is +carbide, but brittle at high speeds. + +![Bantam machine drilling an FR-1 board. My thumb rests on the emergency +stop button.](img/idkhow-pcb/bantam.jpg) + +The drill bit rotates at a nerve-wrecking speed and copper shreds splashed +everywhere (in the protective window, ofc). Each board took 9 minutes in +the machine, plus some extra where I recalibrated the spindle. I had +enough material for 9 of them, so it took around 2 hours. + +![Nine PCBs laid in a grid](img/idkhow-pcb/product.jpg) + +Note that #9 has a defect. Part of the trace wasn't etched deep enough. +I sanded all of them but went too hard on #2 (row 2, column 1). It's kinda +scratchy and I don't wanna risk sanding off everything. So I'm claiming it +as my own and using it as a keyfob. + +![Seven PCBs laid in a stack and another one in +front](img/idkhow-pcb/stack.jpg) + +Overall, this was really cool. I enjoy abusing public resources for my +useless projects, and I will do it again. diff --git a/docs/projects/img/idkhow-pcb/bantam.jpg b/docs/projects/img/idkhow-pcb/bantam.jpg new file mode 100644 index 0000000..1004748 Binary files /dev/null and b/docs/projects/img/idkhow-pcb/bantam.jpg differ diff --git a/docs/projects/img/idkhow-pcb/kicad_pcb.png b/docs/projects/img/idkhow-pcb/kicad_pcb.png new file mode 100644 index 0000000..061ea47 Binary files /dev/null and b/docs/projects/img/idkhow-pcb/kicad_pcb.png differ diff --git a/docs/projects/img/idkhow-pcb/product.jpg b/docs/projects/img/idkhow-pcb/product.jpg new file mode 100644 index 0000000..d92d5da Binary files /dev/null and b/docs/projects/img/idkhow-pcb/product.jpg differ diff --git a/docs/projects/img/idkhow-pcb/stack.jpg b/docs/projects/img/idkhow-pcb/stack.jpg new file mode 100644 index 0000000..d147eef Binary files /dev/null and b/docs/projects/img/idkhow-pcb/stack.jpg differ diff --git a/docs/projects/index.md b/docs/projects/index.md index 3da7848..f28afe3 100644 --- a/docs/projects/index.md +++ b/docs/projects/index.md @@ -8,6 +8,12 @@ MkDocs). But the few that do, are here. Projects below are sorted reverse chronologically (most recent first). +## [I DONT KNOW HOW BUT I MADE A PCB](idkhow-pcb.md) + +![A stack of bare-copper PCBs carrying a logo](img/idkhow-pcb/stack.jpg) + +Imma hand them out at the IDKHOW show on April 5th. + ## [blobcat PCB](blobcat-pcb.md) ![Yellow PCB standing, colorful LEDs in marquee mode. Printed on PCB: -- cgit v1.2.3