# SN-L00 Bill of Materials

## PCBWay Assembly (LCSC parts)

| Ref | Description | Value | Package | LCSC # | Qty |
|-----|-------------|-------|---------|--------|-----|
| C1,C2 | Capacitor, ceramic | 10uF | 0805 | C15850 | 2 |
| C3,C4,C5 | Capacitor, ceramic | 100nF | 0603 | C14663 | 3 |
| R1 | Resistor (button pull-up) | 10K | 0603 | C25804 | 1 |
| R2 | Resistor (LED current) | 1K | 0603 | C21190 | 1 |
| R3 | Resistor (trigger output) | 100R | 0603 | C22775 | 1 |
| R4,R5 | Resistor (input protection) | 10K | 0603 | C25804 | 2 |
| R6 | Resistor (voltage divider) | 22K | 0603 | C25774 | 1 |
| D1 | Schottky diode (reverse polarity) | SS14 | SMA | C2480 | 1 |
| D2 | LED, green (power) | Green | 0603 | C72043 | 1 |
| D3,D4 | Schottky diode (input clamp) | BAT54 | SOD-323 | C181104 | 2 |
| U1 | LDO regulator 3.3V | AMS1117-3.3 | SOT-223 | C6186 | 1 |
| U2 | Schmitt trigger buffer | 74LVC1G17 | SOT-23-5 | C388628 | 1 |
| U3 | Op-amp (input buffer) | MCP6001 | SOT-23-5 | C93025 | 1 |
| J1 | Eurorack power header | 2x5 shrouded | 2.54mm | C429954 | 1 |
| J2,J3 | Thonkiconn jack | PJ398SM | - | C2935955 | 2 |
| SW1 | Tactile switch | 6x6mm | SMD | C127509 | 1 |

**Total unique LCSC parts: 16**

## Hand-Solder Modules

| Ref | Description | Source | Part # | Approx Price | Qty |
|-----|-------------|--------|--------|--------------|-----|
| MOD1 | RP2040-Zero | AliExpress / Waveshare | RP2040-Zero | ~€2-3 | 1 |
| MOD2 | OLED 128x32 I2C | AliExpress | SSD1306 0.91" | ~€2-3 | 1 |

### Alternative sources for modules

**RP2040-Zero:**
- Waveshare official: https://www.waveshare.com/rp2040-zero.htm (~$4)
- AliExpress: Search "RP2040-Zero" (~€2-3)
- Amazon: Search "RP2040-Zero" (~€5-8)

**OLED 128x32 I2C:**
- AliExpress: Search "0.91 inch OLED I2C SSD1306" (~€2)
- Amazon: Search "0.91 OLED Arduino" (~€5-7)
- Adafruit: Product 4440 ($13) - quality option

## Eurorack Jacks (Alternative Sources)

Thonkiconn PJ398SM may have limited LCSC stock. Alternatives:
- Thonk.co.uk: https://www.thonk.co.uk/shop/thonkiconn/ (€0.40/ea, bulk)
- Exploding Shed: https://www.exploding-shed.com/
- Modular Addict: https://modularaddict.com/

## Circuit Description

### Power Section
- **D1 (SS14)**: Reverse polarity protection
- **U1 (AMS1117-3.3)**: 12V → 3.3V LDO regulator
- **C1,C2**: Input/output bulk capacitors (10µF)
- **C3**: Output decoupling (100nF)
- **D2 + R2**: Power indicator LED

### Trigger Output
- **U2 (74LVC1G17)**: Schmitt trigger buffer for clean edges
- **R3 (100Ω)**: Output current limiting / short protection
- **C4**: U2 decoupling (100nF)

### Return Input
- **R4 (10K)**: Input series protection
- **R5/R6 (10K/22K)**: Voltage divider (5V → 3.1V)
- **D3,D4 (BAT54)**: Overvoltage clamp to rails
- **U3 (MCP6001)**: Rail-to-rail buffer op-amp
- **C5**: U3 decoupling (100nF)

### User Interface
- **SW1**: Tactile button (mode/trigger)
- **R1 (10K)**: Button pull-up resistor

## Estimated Costs

| Category | Cost |
|----------|------|
| PCB (5pcs, PCBWay) | ~€5-10 |
| SMD Assembly | ~€15-25 |
| LCSC components | ~€4-6 |
| Hand-solder modules | ~€5-8 |
| Jacks (if separate) | ~€1-2 |
| **Total per unit** | **~€25-40** |

*Prices approximate, bulk reduces significantly*