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Wiring and Hardware
Required components and wiring instructions.
| Part | Role |
|---|---|
| Raspberry Pi 4 Model B/5 and MicroSD card (64GB is plenty) | Runs the SCCS software |
| Raspberry Pi GPIO Tall Header | Because the SCCS is larger than the Raspberry Pi, the USB/network port prevents the Raspberry Pi from connecting to the 40-pin header properly. |
| SCCS Core | Main circuit board that hosts the Raspberry Pi, GPS, lighting dimmers, relays etc. and provides screw terminals for field wiring |
| RGBW LED strips | Or standard white LEDs if bug mode isn't being used |
| Victron SmartShunt | Battery SoC, current, voltage |
| Victron SmartSolar MPPT | Solar charge details |
| Waveshare 10.1" HDMI touchscreen (or similar) | Main UI |
| Radxa Rock 5C or Raspberry Pi 5 | Drives the touchscreen |
| Touchscreen mount | For mounting the touchscreen |
| 12–48 V PoE 5-port switch | Internal LAN/Wi-Fi for Raspberry Pi, screens, WAPs, Sonos |
| Phone hotspot, 5G modem, or Starlink | Internet |
| UniFi WAP(s) | For Wi-Fi |
| Cel-Fi GO | Optional 5G booster (not part of SCCS) |
A 12V power distribution box is a good idea — it makes it easy to add circuit protection and gives you a neat place to step down and distribute cables.
The main circuit board needs to be manufactured by a fabrication house like JLCPCB. PCB design files are in the /kicad folder and are pre-populated with JLCPCB part numbers. Order SCCS Core PCB from JLCPCB by uploading the contents of the /kicad/production folder to JLCPCB. Get PCBA (assembly) done as well - you will receive a warning during the component placement stage that the same component is mapped to multiple parts. This is intentional, tick the checkboxes to include them in the build and continue.
Full schematics are available as a PDF.
There's a 3MF file in the /kicad folder for 3D printing amount that comes with designated screw holes to fix the PCB to a surface. Use 3.5mm standoffs to support the board; any length will do.
Connects to the SCCS via Bluetooth, VE.Bus would probably work too but is untested.
Connect incoming/outgoing cables to the relevant screw terminals. There's no strict requirement on cable size, but during testing:
- 0.75mm shielded figure-8 cable worked for reed switches. The terminals are not polarity sensitive.
- 4-core security cable worked for LED strips. Don't connect the blue channel — it's not supported by this project, and skipping it saves PWM channels. For RGB lighting, use the WS281X outputs instead.
- Size relay channel cables according to their load. 0.75mm figure-8 works up to 7–8A. The relays themselves are rated to 240V, but keep this board to 12V — running 240V through it is a bad idea.
- The analog inputs (water sensor etc.) are not polarity sensitive.
- 4-core shielded security cable worked for the 1-Wire bus.
Due to the electrically noisy environments these boards are installed in, the SCCS Core has generous signal filtering on the screw terminals. Even so, it's recommended to follow these guidelines for field cabling:
- All temp sensors on the 1-Wire bus must be daisy-chained (do not run each sensor back the PCB terminals). When a sensor is connected, a 220Ω resistor should sit in series with the DQ/data pin on the spur/leg to that sensor, not on the bus itself — if the resistor ends up in series with the bus, it's been wired wrong.
- Put 100nF ceramic capacitors across + and − of each temp sensor.
- Put a 220uF 16/25V electrolytic capacitor across 12V and GND at each LED strip.
- Put a 100nF 16/25V ceramic capacitor across 12V and GND at each LED strip (in parallel with the above capactitor).
The capacitors buffer PWM switching transients over the wire run, reduce flicker/sag at the strip end provide some high-frequency filtering.
Testing of temp sensors inside the fridge and freezer showed significant signal interference from the fridge compressor, so use shielded cable wherever possible.
Everything is wired and labelled on the SCCS Core — this table is just for reference.
| GPIO | Physical | Function | Connects to |
|---|---|---|---|
| 0 | 27 | UART2 TX | GPS RX |
| 1 | 28 | UART2 RX | GPS TX |
| 3 | 5 | 1-Wire bus | DS18B20 temperature sensors |
| 4 | 7 | UART3 TX | ESP32-1 RX |
| 5 | 29 | UART3 RX | ESP32-1 TX |
| 8 | 24 | UART4 TX | ESP32-2 RX |
| 9 | 21 | UART4 RX | ESP32-2 TX |
| 14 | 8 | UART1 | Onboard Bluetooth |
| 15 | 10 | UART1 | Onboard Bluetooth |
| 22 | 15 | Relay 1 | Floodlights |
| 10 | 19 | Relay 2 | Water pumps |
| 11 | 23 | Relay 3 | Lighting circuit |
| 6 | 31 | Relay 4 | Fridge/oven |
| 23 | 16 | Reed 1 | Kitchen panel |
| 24 | 18 | Reed 2 | Kitchen bench |
| 25 | 22 | Reed 3 | Storage panel |
| 7 | 26 | Reed 4 | Rear drawer |
| 12 | 32 | Reed 5 | Rooftop tent |
| 16 | 36 | Reed 6 | Spare |
| 20 | 38 | Reed 7 | Spare |
| 21 | 40 | Reed 8 | Spare |
| 18 | 12 | WS281X data out 1 | Addressable LED strip 1 |
| 27 | 13 | WS281X data out 2 | Addressable LED strip 2 |