IoT Blinky

Application name : iot_blinky

Overview

The IoT Blinky sample application is a simple application which is receiving and sending data from/to the cloud. This example requires additional hardware setup to work properly: a push button and an LED need to be connected to the arduino board. The following table shows the necessary connections.

Hardware Connections

Hardware	Pin	Logic
Button	D2	Active LOW
LED	D3	Active HIGH

For more information about the hardware connection, refer the Wiring Diagram With Additional Component.

The working principles of this application are the following: It is fetching data from the cloud from time to time and then reading the response if any. To do this, it is using an action. This is the way to get data from the cloud to the device. To get more information about the Embever IoT Messaging, take a look at the Embever IoT Messaging topic.

After the action is received, the application checks its type and parses the message payload accordingly. Based on that information the external LED will light up or be switched off. Moreover a response for each action will be submitted. In this way, the cloud system can verify the result of an action.

Flashing

Uploading this application to an Arduino compatible board is easy: navigate to the examples and select the iot_blinky from the Embever IoT library in Arduino IDE. Upload the sketch to the board, and see the result in the serial terminal.

Testing the Application

To test the application, the necessary hardware connections should be done (as mentioned before). After powering up the device, the following information should appear in the serial terminal:

IoT Blinky starting...

Pushing the external button will start the fetching process. The following message should appear in the serial terminal:

Fetching...

This means that the application started to look for actions. You should now create the following action in the cloud:

{
    "device": {
        "id": "<<ID>>"
    },
    "type": "setLED",
    "payload": {
        "state": "on"
    }
}

Note replace the <<ID>> placeholder to the the device ID

With the "state":"on" payload, the state of the external LED can be set. With the action creation, the device should change the state of the external LED according to the action. To verify the response from the device, navigate to the corresponding action in the cloud system and see the result. The device should submit the following result and result payload:

"result": {
        "LED": "on"
    },
"result_code": "Success",

Note: The result payload is set by the state of the external LED.

To continue experimenting with the sample application, submit more actions in the cloud system and see the result on the device.

An optional upgrade for this application is to add more LED’s and implement a logic to support them. A possible solution is extending the action payload by adding a led_id key. According to this value, change the corresponding LED state. The new action can be the following:

{
    "device": {
        "id": "<<ID>>"
    },
    "type": "setLED",
    "payload": {
        "led_id": 1
        "state": "on"
    }
}

The new response:

"result": {
        "LED": "on"
        "id":   1
    },
"result_code": "Success",