beagleplay: add nodered guide

Add guide on how to use nodered with BeaglePlay

Signed-off-by: Dhruva Gole <d-gole@ti.com>

boards/beagleplay/05-demos.rst

@@ -64,7 +64,19 @@ Demos and tutorials
     Learn to expand your BeaglePlay capabilities via Qwiic I2C boards.
     +++
     .. admonition:: Complexity level
-        
+
+        beginner
+
+.. card::
+    :link: beagleplay-nodered
+    :link-type: ref
+
+    **Using NodeRed**
+    ^^^
+    Learn how to use NodeRed with BeaglePlay for rapid and easy prototyping.
+    +++
+    .. admonition:: Complexity level
+
         beginner
 
 .. card:: 

boards/beagleplay/demos-and-tutorials/using-nodered.rst

+.. _beagleplay-nodered:
+
+Using Node-RED
+##############
+
+Node-RED provides a browser-based editor that makes it easy to wire together
+flows using the wide range of nodes in the palette that can be deployed to
+its runtime in a single-click.
+
+.. youtube:: 2llY2ZnTmnw
+
+Pre-requisites
+##############
+
+1. Install Node-RED using the `official guide here <https://nodered.org/docs/getting-started/beaglebone>`_
+2. MikroE `Accel click <https://www.mikroe.com/accel-click>`_ or any mikroBUS add-on
+
+Let's get started!
+##################
+
+First, we want to make sure the mikroBUS™ add-on board is connected and functioning as expected.
+To do this, we make use of the `iio_info command <https://man.archlinux.org/man/iio_info.1.en>`_.
+
+Connecting mikroBUS™ add-on board
+*********************************
+
+``iio_info`` is a utility for displaying information about local or remote IIO devices, in this case it's the accel click board.
+
+.. figure:: ./iio_info_out.png
+   :scale: 100
+   :align: center
+
+Accessing Node-RED
+******************
+
+Once your BeaglePlay is booted up and connected to your computer, access it from your browser by typing
+``192.168.7.2:1880`` in your address bar.
+
+Creating a basic flow
+*********************
+
+In this flow we'll take a look at how we can get the accelerometer readings output on the node
+red console.
+
+First, let's insert the exec function block. This will help us capture a linux command from
+an entry like `/sys/bus/iio/...`.
+
+Double click on the function block and in the command paste:
+
+.. code-block:: bash
+   cat /sys/bus/iio/devices/iio\:device0.../in_accel_x_raw
+
+Give it some name and press Done.
+
+Next, we add the "Debug" node and connect it to the previous function block we made
+to get the output.
+
+Optionally, as shown in the video we can also "Inject" a timestamp into the
+function block which will then go into the debug console to give us the logs
+with timestamps.
+
+.. figure:: ./nodered-debug-logs.png
+   :scale: 100
+   :align: center
+
+
+Adding a Gauge
+**************
+
+.. figure:: ./nodered-base-flow.png
+   :scale: 100
+   :align: center
+
+.. figure:: ./nodered-base-flow-output.png
+   :scale: 100
+   :align: center
+
+
+Adding a Graph and 3 Axis
+**************************
+
+.. todo::
+        * Add flow diagram
+        * Show the output
+
+.. figure:: ./nodered-complete-gauges-flow.png
+   :scale: 100
+   :align: center
+