Cloud Communication - Publish

Cloud Communication

iot_cloud

Events Part 1: Publishing Events

  • Events are messages sent from a Photon 2 to the cloud as often as you choose
  • Events are private (viewable by only by you and devices in your account)
  • Events can be accessed in Particle console, app, or by other devices (subscribing)

Events in Particle Console

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Publish Syntax

Particle.publish(<<EVENT_NAME>>, <<EVENT_VALUE>>);

Example

Particle.publish("lightValue", "bright"); 
Particle.publish("tempFahr", String(85.9));
  • Names and values must always be strings
  • Should only publish 1 event / sec (or burst of 4 events in 1 sec)

Publishing on Device Startup

  • With threading enabled, 
    SYSTEM_THREAD(ENABLED);

    setup() will run before cloud connectivity is enabled, meaning Particle.publish() will fail

  • If you need to execute code only once when the device starts, create a boolean flag and check to make sure the Photon 2 has connected to the cloud (Particle.connected()) before running the code once.

  • For example

    bool runOnce = true;
  
void loop() {
  if (runOnce == true && Particle.connected() == true) {
    runOnce = false;
    // put Particle.publish(...) statement here
  }

  • In order to get the weather initially when the Photon 2 turns on, we need to set a boolean flag and do a check in loop()

Documentation

Updated: