PWM Card Planning Guide 

Table of contents
  1. PWM Card Planning Guide
    1. Introduction
    2. Planning Context
    3. Physical Planning Considerations
    4. Uses
    5. References

Introduction

Lighting on a model railroad layout provides visual feedback, realism, and atmosphere, helping convey layout state, time of day, and operational intent.

In the LCC Fusion Project, LED lighting is implemented using the PWM Card, which generates variable-duty PWM outputs in response to LCC events. These outputs are used to control brightness, fading, flashing, and sequencing of LEDs and other low-power loads.

Lighting defines what is shown on the layout; logic, signaling, and automation define when and why it changes. The PWM Card controls output intensity only and never encodes behavior.

Planning Context

PWM planning begins when you decide which visual elements on the layout need dynamic control and why. Each lighting output should exist for a clear purpose, such as conveying status, enhancing realism, or responding to operator or sensor input.

Planning involves determining:

  • Which scene elements require controllable lighting
  • Whether lighting is static, animated, or event-driven
  • How many independent lighting channels are needed
  • How lighting integrates with signals, sensors, buttons, and automation

The PWM Card supports multiple independently controlled outputs, so planning focuses on grouping related lighting elements that can share a card.

Physical Planning Considerations

A PWM Card is installed in a Node Bus Hub and connects via cable to one or more Digital I/O Breakout Boards or Signal Breakout Boards. Breakout boards are typically placed close to the LEDs they serve to minimize wiring complexity and voltage drop.

When planning PWM-controlled lighting:

  • Group nearby LEDs so they can be served by the same PWM Card
  • Separate logic-level wiring from higher-current lighting circuits
  • Consider brightness and duty-cycle requirements rather than raw voltage
  • Plan spare outputs for future scene expansion

Uses

Each use case below represents a reason to introduce PWM-controlled lighting into a layout design. You do not need to implement every item; each entry reflects a potential planning motivation rather than a required feature.

Light Use Description
Train Headlights and Taillights Install LEDs as realistic headlights and taillights on locomotives and cabooses.
Interior Car Lighting Illuminate passenger cars, freight cars, or other rolling stock interiors with small LEDs.
Street Lights Use LEDs to create street lamps that add life and realism to your towns and cities.
Building Lighting Light up windows in houses, office buildings, and other structures to create a lived-in look.
Signal Lights Implement LEDs in railway signals to control train movements, just like in real-world railroading.
Level Crossing Lights Equip level crossings with flashing red LEDs to indicate when trains are passing.
Platform and Station Lighting Illuminate station platforms and buildings for a realistic night-time scene.
Scenery Accent Lighting Use LEDs to highlight landscape features like rivers, cliffs, or trees.
Emergency Vehicle Lights Create realistic emergency scenes with flashing LEDs on police cars, fire trucks, or ambulances.
Vehicle Headlights and Taillights Add headlights and taillights to cars and trucks on roads and highways.
Airport Runway Lights If your layout includes an airport, use LEDs for runway and taxiway lighting.
Dock and Ship Lighting Illuminate docks and ships in maritime-themed areas.
Amusement Park Lighting Create a vibrant and colorful amusement park with LEDs on rides and attractions.
Industrial Area Lighting Light up factories, warehouses, and other industrial structures for a working environment look.
Fire and Explosion Effects Simulate fires or explosions in dynamic scenes using flickering red and orange LEDs.

References

Last updated on: January 12, 2026 © 2026 Pat Fleming