Sending the Messages

The AVR-IoT webpage displays a section called What's Next, two sections below the Light and Temperature graphs. In this section, users can go through the steps of building their own custom application. To quickly preview the capability to send messages from the Cloud to the board, click the Implement a Cloud-Controlled Actuator () icon, and then click the Learn More button to expand the section.

Figure 1. What's Next

Scroll down to the Control Your Device section. Here, control mechanisms can be seen:

The Toggle button is used to send the switch value to the AVR-IoT WA board.

The values are only published over the ‘$aws/things/thingName/shadow/update’ topic upon pressing the Send to device button. Since the board subscribes to ‘$aws/things/thingName/shadow/update/delta’ by default, the shadow service will send updates on this topic when there is a difference in attribute values. The payload received here is limited by the MQTT Receive Buffer (bytes) configurable in MQTT library MCC window (see Figure 3-12 for more details).

Figure 2. Sending Messages on the Subscribed Topic