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+# 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.
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 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: