Alexa™ Blind & Shade Motor Control: Part 6

Alexa™ + Node-RED + BroadLink™: A Dashboard for Controlling Lights

Adrian Biffen, Senior Partner

Please Note: This Alexa™ series assumes you have set up your BroadLink™ hub with the phone app (see home theater article series), and you are running Node-RED IoT visual design on the Raspberry Pi.

The previous Part 5 of this series discussed how the BroadLink™ RF-IR hub (and Alexa™) can be configured to work with the Node-RED system to control blinds and shades.

In this article (Part 6), we'll examine how to enable dashboard switches and buttons that will be the "front end" of the home automation system. This dashboard system will be visible on any wifi enabled device on your local router system (just as the design screens are).

Drag Dashboard Display Nodes Onto the Visual Design Workspace

The picture below is very similar to the setup in part 4 where we switched lights on and off. We have now added one other component: the dashboard user interface switch (2nd item, named "Spots UI") which allows for a "pass-through" configuration.

PLEASE NOTE: The node that follows the DASHBOARD SWITCH is a LOGIC SWITCH. This can lead to confusion as they both have the name - SWITCH - but note that the icons that identify the node type (left side of each node) are very different, as are the colors. We have also renamed the FLOW tabs as LIGHTS, BLINDS, and TEST.

The "Spots UI" dashboard switch instantly and automatically creates an operable switch on the UI (User Interface) DASHBOARD, as shown below. This can be seen in your browser at the same address as the design screen, except that you add a "/UI" designation to the link:

For example, the link to our local Node-RED visual design workspace is:   http://192.168.1.179:1880

So the link to our local Node-RED user interface is the same address + UI: http://192.168.1.179:1880/UI

Synchronizing User Interface Switches with Multiple Device Controls

We have 3 ways of turning on the lights:

• Voice control with Alexa™
• Program control buttons on visual design screen (see Spots ON, Spots OFF injection button nodes in first picture)
• The user interface switch (UI)

There is a potential system design problem, depending on how you "wire" these nodes together. At first we had the UI switch wired as a "dead end" flow, which caused a lack of synchronization between the Alexa™ node and the UI switch on the user interface. If we told Alexa™ to turn on the lights, the UI switch would have no knowledge of this action, and it would stay in the OFF position.

The solution to this problem is simple: USE THE PASS-THROUGH CAPABILIY OF THE UI SWITCH

This picture is captured from the "Spots UI" switch properties dialog that appears when the "Spots UI" node is double-clicked.

You can see the pass-through setting just after the node icon selector: If msg arrives on input, pass through to output

When this option is checked, the control signals flow through this node, regardless of how the lighting system is activated.

The node is "smart" enough to check the trigger signal and determine whether the switch position should be ON or OFF.

This is a very good example of how easy the Node-RED automation system is to set up.

In other systems, this particular problem can often be very difficult to resolve; using Node-RED provides a very easy solution.

There are also other switch settings for UI labels, sizes, icons, etc.

At this point we have created the first control for lights in the Node-RED dashboard interface, and if you have done a similar thing you should be able to click or tap the switch in the user interface (UI) to turn lights ON and OFF.

Conversely, if you use Alexa™, or the design screen inject buttons, you should see the switch turn on and off, tracking your other actions. In the next article we'll do the same with the blinds.

Message Identification Using MQTT Messaging Protocol

In the picture above, most of the other settings are self-explanatory and we won't cover them here. However, there is one that is of particular interest (second from the bottom): TOPIC

The TOPIC parameter refers to an MQTT identification "tag" that you can use to further delineate messages as they flow through a system. We aren't using it in this particular case, because the Alexa™ node has no setting for it, but we will briefly explain its use, as it is quite important.

The MQTT messaging protocol is built into Node-RED; here we will quote the description from the MQTT open source website, and you can study the website for more information:

"MQTT is a machine-to-machine (M2M) 'Internet of Things' connectivity protocol. It was designed as an extremely lightweight publish/subscribe messaging transport. It is useful for connections with remote locations where a small code footprint is required and/or network bandwidth is at a premium."

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Buy The BroadLink™ Hub and Accessory Modules In Our Online Store

In the meantime, we have the excellent BroadLink phone apps that are very capable, and they may very well be all you need (they work stand-alone, the RPi is not needed). This will give you direct control over our blind motors and window openers. Please note that you will need to set up the phone app if you want to implement the system described in this series.

If you are interested, you can purchase these products in our DIY online automation store.

Articles in this series:

Part 1: Alexa™ + RPi + BroadLink™ Hub + Node-RED: Blind Control Introduction

Part 2: Alexa™ + RPi + BroadLink™ Hub + Node-RED: Installing Node Components into Node-RED

Part 3: Alexa™ + RPi + BroadLink™ Hub + Node-RED: Configuring Nodes in Node-RED

Part 4: Alexa™ + RPi + BroadLink Hub + Node-RED: A Simple Flow Example: Light Control

Part 5: Alexa™ + RPi + BroadLink Hub + Node-RED: Control Blind & Shade Motors

Part 6: Creating the Node-RED User Interface Dashboard (you are here)

Part 7: Alexa™ + RPi + BroadLink Hub + Node-RED: Configuring the Dashboard Blackout Blinds