Building The LCC Fusion Node Card

For those interested in model railroad automation, the LCC Fusion Node Card provides device control, power distribution, and network communications with other LCC-enabled devices. The Node Card’s MCU (ESP32) provides the firmware to interoperate with other LCC-compatible systems and interacts with various LCC Fusion Project devices., the LCC Fusion Node Card provides device control, power distribution, and network communications with other LCC enabled devices. The Node Card’s MCU (ESP32) provides the firmware to interoperate with other LCC compatible and interacts with the many LCC Fusion Project devices. This guide walks through the entire assembly process, following the official project documentation step-by-step. Documentation can be found here; https://patfleming.github.io/LccFusionProject/node-card-assembly-guide/

Ordering the PCB and Choosing a Configuration

The first step in building the Node Card is to order the PCB using the provided Gerber files (link found in the Components section). These files ensure a high-quality fabrication from your preferred PCB manufacturer. Once the board is ordered, the next step is to decide on the hardware configuration.

For this build, the CAT-Wired CAN BUS Option was selected, allowing for easy communications and power connections with other NMRA compatible LCC Nodes via standard network cables. This option enables easy daisy-chaining and expands the flexibility of the system.

Printing Assembly Guides for Reference

To simplify the build process:

• Print the PCB image and component list using the printer icon in the documentation.
• Print the color-coded assembly diagram to match components with their correct placements.
• Print the tables for component orientation
• Having a printed reference on hand significantly reduces assembly time and minimizes errors.

Sourcing Components: What You’ll Need

Before starting assembly, it’s helpful to review the Components section in the project documentation. This provides a complete bill of materials, along with links to details about all LCC Fusion components with pricing details and ordering links under Builder’s Resources & Tips. This is especially important for ordering the correct ‘package’ size and ratings.

Essential Components

• Microcontroller: ESP32 DevKitC
• Voltage Regulators: LM2596-5V, LM1117-3V3 (or equivalent)
• Protection Components: TVS diode, Schottky diodes, resettable fuse
• Power Inputs: USB-C, ATX 5557 connector, DC barrel jack (depending on configuration)
• Networking & I/O: RJ45 sockets for CAN and Node Bus, additional I2C and SPI headers
• LED Indicators & Buttons: Power status LEDs, alert LED, CDI reset button

Use the Assembly-Configuration Options table to verify that you have all of the necessary components on hand before proceeding with assembly. Double-check that all components are correctly labeled and match the specified values to avoid errors during assembly.

Preparing the Workspace and Assembling the Board

With all components ready, setting up a clean workspace helps ensure a smooth assembly process:

1. Cleaning and Preparing the PCB

• Wipe the PCB with isopropyl alcohol to remove any manufacturing residue.
• Verify alignment marks to ensure proper orientation.

2. Applying Solder Paste and Stenciling

• Ordering a stencil with the PCB is required for this board, as it allows for quick and accurate paste application across the many SMD components.
• If using a solder paste stencil:
  • Align the stencil using the two small tooling holes.
  • Apply a thin, even layer of solder paste using a squeegee.
  • Remove excess paste before carefully lifting the stencil.

3. Placing Components

• Start with small surface-mount components such as resistors and capacitors.
• Place ICs and voltage regulators next, ensuring correct orientation.
• Through-hole components like connectors, headers, and large capacitors are added last.
• Use the provided tables in the assembly documentation to correctly orient all components.
• Note that additional optional components and parts can be added later using a soldering gun and/or heat blower. Because of possible damage to components and parts, it is not recommended to perform a 2nd reflow after PTH components have been added.

4. Reflow Soldering or Hand Soldering

• If using reflow soldering, preheat your oven and follow recommended temperature profiles.
• For hand soldering, use a fine-tip soldering iron at 350–375°C with flux for clean joints.

5. Inspecting Solder Joints

• Use a magnifying glass or microscope to check for cold joints, bridges, or missing connections.
• Reflow any problematic areas with a heat gun or soldering iron.

Configuration and Testing

1. Verifying Electrical Continuity

Before applying power:

• Use a multimeter in continuity mode to check for shorts between VCC and GND.
• Verify that critical power paths are intact.

2. Powering Up the Board

• If using a bench power supply, start with current limiting enabled to prevent damage.
• If using a 12V or 5V adapter, confirm correct polarity before connecting.

3. Checking Node Bus and CAN Communications

To verify CAN and I2C communication:

• Connect the Node Card to another LCC device using an RJ45 cable.
• Open a serial monitor on your computer and check for successful CAN bus initialization.
• Run an I2C scan to detect connected I/O devices.

4. Flashing the ESP32 Firmware

Once power and communication are verified:

• Use the provided firmware flashing tool to install the Node Card firmware.
• Open a serial monitor (e.g., YAT or Arduino Serial Monitor) to check startup messages.
• If necessary, use the CDI reset button to restore factory settings.

Parts List

To assist you in sourcing the necessary components for building the node card, we’ve compiled a comprehensive parts list from AliExpress.com. This table details each component, the supplier, pricing, and quantities required, providing a clear overview to streamline your assembly process.

Final Thoughts

The LCC Fusion Node Card is a versatile addition to any model railroad automation project, providing interoperability with other LCC Nodes in your network and communicating with LCC Fusion cards for automation. By following the documented process, assembling the board becomes an **accessible and repeatable task.

Key Takeaways:

✅ Ordering a stencil with the PCB ensures quick and accurate paste application. ✅ Printing the color-coded assembly diagram simplifies component placement. ✅ Using the provided tables ensures correct component orientation. ✅ Verifying continuity before power-up helps prevent damage. ✅ Testing CAN/I2C communication ensures seamless integration with other LCC nodes.

For those planning their own build, the documentation provides everything needed to get started.

• 2025 8