Files
florian.berthold d43c7976ad Add panel-to-PCB mounting system with M3 standoffs
Panel alignment:
- PCB offset 10mm from panel top
- Component holes aligned: OLED@25mm, jacks@45mm, button@58mm
- 4x M3 standoff holes at corners (5,5), (35,5), (5,75), (35,75)

Updates:
- Panel SVG and spec aligned with PCB layout
- Mounting holes added to PCB (Edge.Cuts layer)
- Regenerated Gerbers with mounting holes
- Updated autoroute.py to add mounting holes automatically

DRC: 0 unconnected, 7 cosmetic errors (courtyard overlaps)
2026-01-23 08:15:25 +01:00
..

SN-L00 KiCad Project

Schematic Overview

                            +12V (from Eurorack)
                              │
                              ▼
┌─────────────────────────────────────────────────────────────────┐
│  POWER SECTION                                                   │
│                                                                  │
│   J1 (2x5)        D1 (SS14)       U1 (AMS1117-3.3)              │
│   Eurorack ──────►Schottky──┬────►LDO────────────► +3.3V        │
│   Header         protection │     │                              │
│                            C1    C2,C3                           │
│                           10uF   10uF+100nF                      │
│                             │     │                              │
│                            GND   GND                             │
└─────────────────────────────────────────────────────────────────┘

┌─────────────────────────────────────────────────────────────────┐
│  MCU & DISPLAY                                                   │
│                                                                  │
│   MOD1 (RP2040-Zero)              MOD2 (OLED 128x32)            │
│   ┌─────────────┐                 ┌──────────┐                   │
│   │ 3V3     5V  │                 │ GND      │                   │
│   │ GND     GND │                 │ VCC      │◄── +3.3V          │
│   │ GP0     GP9 │──SDA───────────►│ SDA      │                   │
│   │ GP1     GP8 │──SCL───────────►│ SCL      │                   │
│   │ GP2     GP7 │──TRIG_OUT       └──────────┘                   │
│   │ GP3     GP6 │──RETURN_IN                                     │
│   │ GP4     GP5 │──BTN                                           │
│   │ GP29    3V3 │                                                │
│   │ GND     GND │                                                │
│   └─────────────┘                                                │
└─────────────────────────────────────────────────────────────────┘

┌─────────────────────────────────────────────────────────────────┐
│  TRIGGER OUTPUT                                                  │
│                                                                  │
│   GP2 ────► U2 (74LVC1G17) ────► R3 (100Ω) ────► J2 (TRIG OUT)  │
│            Schmitt buffer        current limit   3.5mm jack      │
│                 │                                                │
│                C4 (100nF) to GND                                 │
└─────────────────────────────────────────────────────────────────┘

┌─────────────────────────────────────────────────────────────────┐
│  RETURN INPUT                                                    │
│                                                                  │
│   J3 (RETURN) ──► R4 (10K) ──┬──► R5/R6 divider ──► U3 ──► GP3  │
│   3.5mm jack     protection  │   (10K/22K = 0.69x)   MCP6001     │
│                              │                       buffer      │
│                              ├── D3 to +3.3V (clamp high)        │
│                              └── D4 to GND (clamp low)           │
│                                  BAT54 Schottky                  │
└─────────────────────────────────────────────────────────────────┘

┌─────────────────────────────────────────────────────────────────┐
│  BUTTON                                                          │
│                                                                  │
│   +3.3V ──► R1 (10K) ──┬──► GP4                                 │
│             pull-up    │                                         │
│                       SW1 ──► GND                                │
│                       tactile                                    │
└─────────────────────────────────────────────────────────────────┘

┌─────────────────────────────────────────────────────────────────┐
│  POWER LED                                                       │
│                                                                  │
│   +3.3V ──► R2 (1K) ──► D2 (Green LED) ──► GND                  │
└─────────────────────────────────────────────────────────────────┘

RP2040-Zero Pinout Reference

        ┌─────────────────┐
   5V ──┤ 5V          3V3 ├── 3.3V
  GND ──┤ GND         GND ├── GND
 GP29 ──┤ GP29        GP0 ├── I2C SDA → OLED
  GP28 ──┤ GP28        GP1 ├── I2C SCL → OLED
  GP27 ──┤ GP27        GP2 ├── TRIG_OUT → 74LVC1G17
  GP26 ──┤ GP26        GP3 ├── RETURN_IN ← MCP6001
 GP15 ──┤ GP15        GP4 ├── BTN (active low)
  GP14 ──┤ GP14        GP5 ├── (spare)
        └─────────────────┘
          USB-C on bottom

Files

  • SN-L00.kicad_pro - KiCad project file
  • SN-L00.kicad_sch - Schematic (open in KiCad 8+)
  • SN-L00.kicad_pcb - PCB layout
  • PCB_LAYOUT.md - Component placement guide

Custom Libraries

Symbol Library (SN-L00.lib/)

Symbol Description
RP2040-Zero Waveshare RP2040-Zero module (18 pins)
OLED_128x32_I2C 0.91" OLED display (4 pins: GND, VCC, SCL, SDA)

Footprint Library (SN-L00.pretty/)

Footprint Description
RP2040-Zero 2×9 pin through-hole, 15.24mm row spacing
OLED_128x32_I2C 38×12mm module with 4-pin header

Libraries are auto-loaded via fp-lib-table and sym-lib-table.

RP2040-Zero Pinout (Footprint)

Pin  Name     │ Pin  Name
─────────────┼─────────────
 1   5V      │ 10   3V3
 2   GND     │ 11   GND
 3   3V3     │ 12   GP0/SDA
 4   GP29    │ 13   GP1/SCL
 5   GP28    │ 14   GP2
 6   GP27    │ 15   GP3
 7   GP26    │ 16   GP4
 8   GP15    │ 17   GP5
 9   GP14    │ 18   GND

OLED Pinout (Footprint)

Pin  Name
───────────
 1   GND
 2   VCC
 3   SCL
 4   SDA

Design Notes

Power

  • Single +12V rail used (no -12V needed)
  • AMS1117-3.3 LDO provides 3.3V for MCU and peripherals
  • SS14 Schottky for reverse polarity protection
  • Total current draw ~20-30mA

Trigger Output

  • 74LVC1G17 provides clean Schmitt-trigger buffered output
  • 100Ω series resistor for short-circuit protection
  • Output: 0-3.3V (compatible with most Eurorack gate inputs)

Return Input

  • Handles 0-10V Eurorack signals safely
  • 10K/22K voltage divider scales to ~0-3.1V
  • Schottky clamp diodes protect against overvoltage
  • MCP6001 rail-to-rail op-amp buffers signal
  • Threshold set in firmware (~1.5V default)

I2C

  • 400kHz I2C to OLED display
  • No external pull-ups needed (internal to OLED module)

Opening the Project

  1. Install KiCad 8.0+
  2. Open SN-L00.kicad_pro
  3. Schematic editor opens automatically