UOD Breakout Board Assembly Guide

Table of contents

1. UOD Breakout Board Assembly Guide
   1. Introduction
   2. Assembly and Component Placement
   3. Tools Required
   4. Safety Precautions
   5. Testing and Verification
      1. Visual Inspection
      2. Functional Testing
   6. Troubleshooting
   7. Appendences
      1. Specifications
      2. How It Works
      3. Connections
      4. References

Introduction

The Ultrasonic Occupancy Detection (UOD) Breakout Board, used in combination with the UOD Card and the Node Card, simplifies wiring for monitoring object proximity using ultrasonic sensors. The breakout board connects to up to five ultrasonic sensors, allowing for the detection of objects within a configurable range.

The UOD Card receives echo signals from each sensor and provides status updates to the LCC Fusion Node Card via its GPIO pins. The Node Card firmware interprets these signals and generates corresponding LCC events, enabling layout automation—for example, triggering lighting effects when a person approaches the train layout.

flowchart LR; 
can["CAN Network"];
subgraph layout ["Train Layout"];
  direction LR;
  uod[["UOD Card (16x)"]]
  nodecard[[Node Card]]; 
  object(("Object (person)"))
  device("UOD Sensor");
  bb[UOD Breakout Board];

  object -.->|"Sound Waves"|device 
  device --> |"Analog signal"|bb;
  bb -->|"Analog signal"| uod;
  uod -->|"GPIO Output <br/> High/Low"| nodecard;
  nodecard -->|"LCC Event <br/> (occupied/unoccupied)"| can;
end;
classDef lSalmonStyle fill:#FFA07A,stroke:#333,stroke-width:2px,font-size:20px;
class bb lSalmonStyle;
classDef lightGrayStyle fill:#d3d3d3,stroke:#333,stroke-width:2px,font-size:24px;
class layout lightGrayStyle; 

## Terminology

• Cleaning PCB

• Component

• LCC Fusion Breakout Boards

• LCC Fusion Cards

• lcc_fusion_node_card - not defined

• LCC Fusion Project

• Network Cable

• Track Bus

For other terms, please refer to the full Terminology Guide.

Assembly and Component Placement

This section combines both the component specifications and the assembly instructions to ensure a smooth assembly process. Below is a comprehensive list of components, their placement on the PCB, and orientation details to assist you during assembly.

High-Level Steps for Assembly:

• PCB for the card can be ordered from any PCB fabricator using these Gerber Files.
• Clean PCB with alcohol to remove residue. See Cleaning_PCB for details.
• See also: Soldering Tips
• PCB Components - listing of components used for PCB assembly
• PCB Parts - listing of parts used for PCB assembly

Below is a list of the PCB components used for this card (see diagram before reference):

Component Identifier	Count	Type	Value	Package	Purpose	Orientation
Connectors
J1-J5	5	JST XH Socket or 4-Position Spring Terminal Connector	4P, 2.54mm	PTH, vertical or horizontal	Connectors sensors	Position connection outward
J6	1	RJ45 Socket	8P8C	PTH	Network cable (CAT5/6) connection from UOD Card.	Fits only one way

Tools Required

List of recommended tools.

Safety Precautions

• See Safety Precautions.

Testing and Verification

Visual Inspection

1. Initial Check: Examine the board for any obvious issues like missing components, solder bridges, or components that are misaligned or not fully seated.
2. Solder Joint Inspection: Use a magnifying glass or a microscope to inspect solder joints. Look for cold solder joints, insufficient or excessive solder, or any shorts between pads.
3. Use an Digital Multimeter (DMM) to test for continuity between:
   • RJ45 socket pins (2, 4, 6, 8) and the 4 block connectors (J1, J2).
   • RJ45 socket pins (1, 3, 5, 7) and the Track Bus B connector (J3)

Functional Testing

Refer to UOD Card for details on testing the UOD Breakout Board with the UOD Card.

Troubleshooting

• See I2C Trouble Shooting.

Appendences

Specifications

Specifications for the UOD Breakout Board include:

Characteristic	Value
Sensors	5

How It Works

The UOD Breakout Board connects up to five ultrasonic distance sensors (such as the HC-SR04) to the UOD Card using a single RJ45 cable. The breakout board distributes shared power and trigger signals to all connected sensors while routing each sensor’s echo signal back individually to the UOD Card.

1. The UOD Card sends a brief HIGH pulse (~10 µs) on the shared TRIG line.
2. All connected sensors receive this pulse simultaneously.
3. Each sensor sends a HIGH pulse on its ECHO pin; the duration of this pulse corresponds to the distance to the nearest object.
4. The UOD Card measures this pulse width on one ECHO line at a time to determine distance.

To avoid signal collisions, the UOD Card firmware must trigger and measure only one sensor at a time, even though the TRIG line is shared.

The board uses a 4-pin connector per sensor:

• GND – Shared power ground
• 5V – Shared 5V supply from the UOD Card
• TRIG – Shared trigger line; the UOD Card sends a pulse to initiate distance measurement
• ECHO – Individual signal line returning the measured pulse width to the UOD Card

RJ45 Line Assignments

RJ45 Line	Signal Name	Function
L1	GND	Shared ground for all 5 sensors
L2	5V	Shared 5V power to all sensors
L3	TRIG	Shared trigger signal from UOD Card
L4	S1 (Echo 1)	Pulse-width signal from Sensor 1
L5	S2 (Echo 2)	Pulse-width signal from Sensor 2
L6	S3 (Echo 3)	Pulse-width signal from Sensor 3
L7	S4 (Echo 4)	Pulse-width signal from Sensor 4
L8	S5 (Echo 5)	Pulse-width signal from Sensor 5

Connections

The purpose of the UOD Breakout Board and its connectors is to facilitate quick and easy connections between the UOD Card and the track rails. For setups with multiple distant blocks, breakout boards can be daisy-chained together, or a network cable with a splitter can be used to provide multiple connections efficiently.

Component Designator	Connector Label	Connector Type	Connection Number	Description
J1-J5	TO SR04 x	JST XH, Spring Terminal	GND, 5 V, TRIG, ECHO	Connection so SR04 Sensor
J6	UOD CARD	RJ45 Socket	GND, 5 V, S1, S2, S3, S4, S5	Power and 5x sensor lines (pulse width from sensor)

References

• Preparing a PCB for Soldering
• Solder Tips

• Breakout Board Signal Mapping (UOD Breakout Board)

  This breakout board connects up to 5 ultrasonic distance sensors (e.g., HC-SR04) using a 5-wire interface per sensor. All sensors share power (GND, 5V) and the trigger line (TRIG). Each sensor has a dedicated Echo line (S1–S5), which returns the measured pulse width to the UOD Card.

  RJ45 Line	Signal Name	Direction	Purpose	Notes
  L1	GND	Output	Ground for sensors	Shared among all 5 sensors
  L2	5V	Output	Power for sensors	Shared among all 5 sensors
  L3	TRIG	Output	Trigger signal to all	Simultaneously pings all sensors
  L4	S1 (Echo 1)	Input	Echo return from Sensor 1	Pulse width corresponds to distance
  L5	S2 (Echo 2)	Input	Echo return from Sensor 2	Pulse width corresponds to distance
  L6	S3 (Echo 3)	Input	Echo return from Sensor 3	Pulse width corresponds to distance
  L7	S4 (Echo 4)	Input	Echo return from Sensor 4	Pulse width corresponds to distance
  L8	S5 (Echo 5)	Input	Echo return from Sensor 5	Pulse width corresponds to distance