Controller board: ESP32 + 2x StepStick carrier (v0.4), FluidNC config

- KiCad project generated by pcb/tools (design, route, schematic, fab outputs).
- v0.4 fixes the v0.3 review findings: low-dropout 3.3 V regulator, OR'd 5 V
  supply, polyfuse, USB ESD protection, input clamps, ceramic decoupling at the
  drivers, A4988/DRV8825 jumper, ground stitching. DRC/ERC clean.
- v0.3 (as ordered) kept in pcb/archive/v0.3.
- FluidNC config.yaml for the board; rho hard limit on.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

pcb/pcbway-order/ORDER.md

@@ -0,0 +1,53 @@
+# PCBWay order: SandTable Controller v0.4
+
+## Files
+
+| File | Where it goes |
+|---|---|
+| `1-gerbers-sandtable-controller-v0.4.zip` | PCB order: **Upload Gerber file** |
+| `2-bom-sandtable-controller-v0.4.csv` | Assembly order: **BOM file** |
+| `3-centroid-sandtable-controller-v0.4.csv` | Assembly order: **Centroid / pick-and-place file** |
+| `assembly-top-v0.4.pdf` | Attach if PCBWay asks for an assembly drawing |
+| `schematic-v0.4.pdf` | Attach if PCBWay asks for a schematic |
+
+## PCB settings
+
+| Setting | Value |
+|---|---|
+| Board type | Single pieces |
+| Size | 80 x 63.34 mm |
+| Quantity | 5 (the minimum) |
+| Layers | 2 |
+| Material | FR-4, TG130-140 |
+| Thickness | 1.6 mm |
+| Min track / spacing | 6/6 mil |
+| Min hole size | 0.3 mm |
+| Solder mask / silkscreen | any colour / white |
+| Surface finish | HASL lead-free (or ENIG) |
+| Via process | Tenting vias |
+| Finished copper | 1 oz |
+| Product No. | Specify a location (the back of the board has a "WayWayWay" marker for it) |
+
+## Assembly settings (PCB Assembly quote)
+
+| Setting | Value |
+|---|---|
+| Service | Turnkey (PCBWay buys the parts) |
+| Assembly side | Top side only |
+| Quantity | 1 or 2 (fewer than the 5 bare boards is fine) |
+| Unique parts | 31 |
+| SMD parts | 47 |
+| BGA / QFP parts | 0 |
+| Through-hole parts | 12 (10 designators; each driver socket is 2 headers) |
+| Accept alternatives | Yes, for lines marked "Any brand" |
+
+**Note for PCBWay** (paste into the comments box):
+
+> Please fit the female header sockets for A1 and A2 only. Do not supply the stepper driver modules; I will plug in my own. BOM lines marked "Any brand" may use any equivalent part to the description. U3 (AP7361C-33E) has a different pinout from AMS1117-type regulators, so please do not substitute it. Leave solder jumper JP1 open. C16 and C17 sit between the driver socket strips, under where the modules plug in; that is intended. Centroid coordinates are in mm, with the origin at the board's bottom-left corner.
+
+## When PCBWay sends their review
+- Check the polarity of C1, C2 (electrolytic), D1-D3, D6, D7 (diodes) and D4, D5 (LEDs) against the + and bar marks in `assembly-top-v0.4.pdf`.
+- Check that the ESP32 (U1) antenna end sits at the board edge, over the copper-free area.
+- Check that pin 1 of U2, U3, U4 and U5 is at the dot or triangle on the silkscreen.
+- U3 is an AP7361C-33E, not an AMS1117: its pinout is different (pin 1 IN, pin 2 GND/tab, pin 3 OUT), so it must not be swapped for a 1117-type regulator.
+- JP1 is a solder jumper (bare pads), not a part: leave it open.