Dash Button
=============

| Application name : ``dash_button``

Overview
**********

The Dash Button sample application is a simple application which is sending data 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.

.. list-table:: Hardware Connections
   :widths: 25 25 25
   :header-rows: 1
   :align: center

   * - Hardware
     - Pin
     - Logic
   * - Button
     - D2
     - Active LOW
   * - LED
     - D3
     - Active HIGH

| For more information about the hardware connection, refer the :ref:`wiring_led_btn`.

..
    TODO: Add the wiring diagram
    I couldn't find it. We should mention the file name here

The working principles of this application are the following: it sends data to the cloud at every button presses.
To achieve this task, it is using an event. This is the way to send data from the device to the cloud. To get
more information about the Embever IoT Messaging, take a look at the :ref:`ebv-iot-msg` topic.

Flashing
***********

Uploading this application to an Arduino compatible board is easy:
navigate to the examples and  select the ``dash_button`` 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:

.. code-block:: none

    DashButton demo starting...

To send the event to the cloud press the external button.
The external LED will light up for 15 seconds.

To verify the event which is just sent, go to the cloud system and check the events.
Should look like the following:

.. code-block:: JSON

    {
        "type": "buttonPressed",
        "payload": {
            "name": "1"
        }
    }

To continue experimenting with the sample application, press the external button several times.
A possible upgrade for this application is to add and implement more external triggers (like buttons) and change the
``name`` value according to the trigger source.