8. Modules & Extensions

SMHUB is designed to be modular. The main board provides essential radios, networking, and I/O, while additional hardware modules extend functionality for power resilience, connectivity, and advanced integrations.

8.1 USB Passthrough

• Purpose: Enables SMHUB to act either as a USB host (powering connected peripherals) or as a USB device (connected to a PC or another host).

• Logic:

  • Automatically decides whether to supply or draw power.

  • Prevents reverse powering through integrated FET switching.

• Use Cases:

  • Attach Z-Wave or extra Zigbee dongles, printers, audio devices, storage etc.

  • Connect SMHUB to a PC for development/debugging.

  • Power downstream devices safely.

8.2 SD Card

• Slot: Standard microSD slot on the main board.

• Purpose: Expand storage for logs, app data, or backups.

• Integration:

  • Mounted automatically by the Linux OS.

  • Users can format, mount/unmount, and monitor usage from the UI.
  • Support up to 2Tb volume.

8.3 PoE Module

• Standard: IEEE 802.3af-compliant.

• Input: Power delivered via Ethernet cable from a PoE-enabled switch or injector.

• Output: Stable 5V regulated supply to the hub.

• Protection: Surge and ESD protection integrated.

• Monitoring: “PoE Power Check” exposed in the system for telemetry.

• Use Case: Ideal for enterprise deployments where powering over Ethernet is standard.

8.4 UPS Module

• Battery: Supports 18650 Li-ion cells (user-installed).

• Charger: advanced circuit with overcharge/undervoltage protection.

• Conversion: Step-up/step-down converters to maintain 5V, 3.3V, 1.8V rails.

• Telemetry:

  • Monitors voltage/current

  • Provides battery health and charge state in the UI.

• Inputs: Can also accept DC power or solar panels, making SMHUB deployable off-grid.

• Use Case: Ensures uninterrupted operation during outages.

8.5 4G/LTE Module

• Connectivity: LTE Cat 1 with fallback modes.

• Interfaces:

  • Main UART.

  • USB.

  • Debug UART.

• SIM Slot: NanoSIM with detection circuitry.

• Antennas: Dedicated connectors for LTE and GNSS.

• UI Integration:

  • Settings → Radios → 4G/LTE.

  • SIM/APN configuration, LTE signal telemetry.

• Status: Hardware available, software support in development.

8.6 DIY Pinouts & Interfaces

For advanced users and developers, SMHUB exposes additional hardware interfaces:

• GPIO pins for general use.

• UART, SPI, and I²C buses.

• Custom module connectors for prototyping or specialized hardware.

• Use Case: Attach sensors, control boards, or experimental expansions not covered by official modules.

8.7 Integrated Peripherals

While not separate modules, the following are considered part of SMHUB’s extension capabilities:

• IR Transmitter & Receiver

  • Control TVs, AC units, and IR-based devices.

  • Capture IR codes for learning mode.

• Audio Output (3.5 mm)

  • System alerts and future media/streaming support.

• Buzzer

  • Local audible notifications.

• LED Systems

  • 12 WS2812B RGB LEDs (Ambilight) – running by default, user configurable.

  • 4 Service LEDs – network, power, radio status.