Blueprint – Beginner – Hello World Publish

Difficulty: Beginner
Estimated Time: 15–30 minutes
Hardware Needed: None
Particle Features: Particle.publish(), Particle.function(), Console, Logs

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Overview

This blueprint demonstrates how to publish a simple “Hello World” event to the Particle Cloud whenever a cloud function is called.
It’s the ideal first step for understanding how Particle devices communicate with the cloud and respond to Console or API actions.

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Tools & Materials

• Any Particle device (Photon 2, Boron, Argon, etc.)
• USB cable
• Particle Workbench or Particle CLI
• A Particle account with a claimed device

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Steps

1. Clone this repository:

   git clone https://github.com/particle-iot/blueprint-beginner-hello-world-publish.git
   cd blueprint-beginner-hello-world-publish

2. Open the project in Particle Workbench or your preferred editor.
3. Flash the firmware to your device.

   particle flash <device-name>

4. Call the function from the Particle Console:
   • Go to the Functions section.
   • Select the function named sayHello.
   • Click Call (no arguments required).
5. View the result under Logs. You should see an event named hello_world with data:

   Hello from Particle!
   

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How It Works

• In setup(), the firmware registers a cloud function named sayHello.
• When called from the Console or API, this function executes sayHelloHandler().
• The handler uses Particle.publish() to send a private event called hello_world to the cloud.
• All events are visible in the Console’s Logs tab and can also be received by webhooks, integrations, or other devices.

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Source Code

The main firmware is located in /src/hello-world-publish.cpp.
It’s fully commented to explain how the cloud function and publish mechanism work.

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Example Firmware

(firmware\blueprint-begineer-hello-world-publish\src\hello-world-publish.cpp)

/*
 * Project: Hello World Publish
 * Author: Your Name
 * Date: YYYY-MM-DD
 *
 * Description:
 *  This example demonstrates how to register a cloud function that,
 *  when called, publishes a "Hello World" event to the Particle Cloud.
 *  The event will appear in the Particle Console → Logs section.
 *
 * For comprehensive documentation and best practices, visit:
 * https://docs.particle.io/firmware/best-practices/firmware-template/
 */

#include "Particle.h"

SYSTEM_MODE(AUTOMATIC);
SYSTEM_THREAD(ENABLED);
SerialLogHandler logHandler(LOG_LEVEL_INFO);

int sayHelloHandler(String command);

void setup() {
    Particle.function("sayHello", sayHelloHandler);
    Log.info("Setup complete. Cloud function 'sayHello' is ready.");
}

void loop() {
    delay(100);
}

int sayHelloHandler(String command) {
    Log.info("Cloud function called with command: %s", command.c_str());
    Particle.publish("hello_world", "Hello from Particle!", PRIVATE);
    Log.info("Published 'hello_world' event to the cloud.");
    return 1;
}

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Expected Output

Console logs:

Event: hello_world
Data: Hello from Particle!

Serial logs (from particle serial monitor --follow):

0000012345 [app] INFO: Cloud function called with command:
0000012346 [app] INFO: Published 'hello_world' event to the cloud.

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Extensions

• Modify the handler to publish a message containing your device name.
• Schedule automatic publishes using a software timer.
• Add a button that triggers the same event locally.