This example demonstrates how to establish a connection with a Voyant LiDAR sensor and capture incoming frames.

What You’ll Learn

  • How to create a VoyantClient instance
  • How to handle multicast connections
  • How to receive and process frame data
  • Basic signal handling for graceful application termination

Prerequisites

  • Voyant API installed (see Installation)
  • A Voyant LiDAR sensor (or sensor simulator running in loopback mode)

Example Code

View the complete example on GitHub: voyant_client_basic.cpp

Key Concepts

This example demonstrates the basic usage of the VoyantClient class.

Signal Handling

The VoyantClient::setupSignalHandling() method configures the application to gracefully handle interruption signals (like Ctrl+C), allowing for proper cleanup when the program terminates.

Client Configuration

The VoyantClient constructor takes three parameters:

  • Local binding address and port
  • Multicast group address
  • Interface address

The example provides both loopback configuration for testing and real-world sensor configuration. Refer to our Connections Guide for more information.

Frame Capture Loop

The main loop:

  1. Checks if the application has been terminated (via signals)
  2. Attempts to receive the next frame from the sensor
  3. Processes the frame data if available
  4. Sleeps briefly to avoid consuming excessive CPU resources

In this example we return a mutable reference to the latest received frame.

// Access latest frame as a mutable reference
VoyantFrameWrapper &frame = client.latestFrame();

You can also receive an immutable reference by decorating with the const keyword.

// Access latest frame as an immutable reference
const VoyantFrameWrapper &frame = client.latestFrame();

Or you can make a copy of the latest frame by removing the &, but be warned this will allocate a large chunk of memory every time.

// Make a copy of the latest frame
VoyantFrameWrapper frame = client.latestFrame();

Building and Running

You can build and run this example using CMake:

  • From /workspace/ if building in provided docker container.
  • From voyant-sdk/ if building on your native system.
# Build the examples
mkdir build && cd build
cmake ..
make

# Run the basic client example
./bin/voyant_client_basic

Expected Output

When running in loopback mode with a sensor simulator, you should see output similar to:

If properly configured, your basic client will display a stream of received full LiDAR frames:

###############
Received frame:
Header{message type:2, device id:MDL-000, frame idx:35, stamp:1691391379.087802875, proto version:0.1.0, api version:0.1.0, fw version:0.1.0, hdl version:0.0.34}
Config{ len: 0 }
Points[24384] {{idx:6238209,ts:163840,pos:[43.984,0.193966,11.0427],v:1.22985,snr:12.3234,refl:0,noise:34.0003,min_snr:-0.00802298,drop reason:1},...}

Next Steps

After understanding this basic example, you might want to explore:

  • How to process the point cloud data within frames

See our other examples or refer to the API Documentation for more advanced usage.

Copyright © Voyant Photonics, Inc.