HA: MQTT + Node Red

Message Queue Telemetry Transport is a lightweight publish / subscribe message transport.  For example Sensor hardware publishes values which the MQTT Broker passes on to all subscribers.
Alternatively a client can publish an instruction (topic) which wll be passed on by the MQTT Broker to all subscribers for action.
There are lots of MQTT resources/tutorials, for example at mqtt.org

Home Assistant has an integration for an MQTT Broker which can be utilised with a wide variety of devices. Typically, for me, the client will be an ESP8266 or ESP32.  For testing I use a NodeMCU ESP8266 and the Arduino IDE.

HA has an integration for the Mosquitto MQTT Broker which is widely used and very easy to install on HA. I used a good video by EverythingSmartHome. Once the install has completed the broker provides you with a screen where you can experiment, sending packets and listening to Topics.  This will be very useful going forward to watch messages flowing through the system.

I followed a good tutorial from emqx.com to setup a NodeMCU ESP8266 as an MQTT client.  It uses the ESP8266WiFi library and PubSubClient which is allows messages to be published / received.

Our inital sketch simply sets up wifi, sets up MQTT client and publishes a "hello" message which is promptly displayed on the Broker Topic Monitor.
The sketch is very straightforward so I have included it below.  

We dont have sensors attached on functions to carry out yet but you can see how easy they will be to add.

Node Red is a HA add-on / integration which allows you to configure how devices interact using flow diagrams.  I set up a simple test using my ESP8266 keypad and MQTT.  With the help of the Hook Up Guy I was quickly able to use Node Red to instruct HA to say a phrase when button 7 or 8 are pressed.  This isn't a trivial exercise and it is impressive that Node Red plus the wizardry linking it to HA makes it so easy.

HA : Practical Music Solution

 I can probably spend months tinkering with Home Assistant and Google Assistant without having something practical.  I need to remember that the solution needs to help me in practice rather than include clever esoteric features which I wont use.

Home Assistant

I settled on two HA dashboard screens, the first is for MPD playlists and the second for radio/music  streams.

My existing, excellent, solution for music is an RPI running MPD with an extensive music database.  In most cases I will use a webpage to choose music so I include this webpage on my dashboard.

Any specific selections I want to have under voice control are set up with an input select card.  Initially I set this up for three albums and a charts playlist but I can easily add more options if they prove useful.  Only these four music selections are available using voice control, but that is ok.  I do have voice control for general purpose changes such as volume up/down, next track, play, pause, shuffle on/off. 

My second screen is for Pure Jongo Job control.  Typically I use this for playing radio stations so I set it up for common stations I listen to together with a few music streams which I may expand later.  Jongos dont have so many control options but pause / resume will be important.

Both the MPD and Jongo options run through my Sony amplifier so I have options to switch between the two music sources and amplifier volume up/down.

Google Assistant

The Home Assistant configuration has given us various capabilities to control music using Linux Music Player and Pure Jongos.  However we had this capability previously and our main objective is to have voice control of sounds.  Home Assistant provides us with an automated IR (infrared) remote control to "press buttons" so the final piece is to add voice control.

Google Assistant controls some devices with voice and Google Home lets us setup routines for "Hey Google" commands which carry out a wider variety of activities.  Activities provided within Google Home are very limited for my devices; I can only turn lights on/off and tell the Nest Mini to say things.  However I can import all scripts from HA to GH and invoke any of them with a voice command.

This provides exactly what we need; as long as we have a HA script for a function we can invoke it using a voice command.  To start off with my Broadlink HA integration allows me to change the volume and switch between MPD and Jongo output and HA can pause / resume devices.
Google Home doesn't allow me to specify parameters / variables so I need to set up a script in HA for each playlist / album / radio station I want to control with voice.  Once these have been imported into Google Assistant I can easily add voice commands.

It is easy to get carried away add functions, which I wont use.  For voice control it is even easier to add commands which I don't remember so I cant use.  The sensible way forward is to limit voice control to frequently used functions such as playing radio stations and changing the volume.  I set them up in a spreadsheet so that I can keep track of what is available to me.

I should also mention that Google Assistant provides an alternative to many web browser functions.  I can easily ask it for the weather forecast, information and news, although it is more difficult to phrase requests so that I get something meaningful.
Perhaps the most useful function is "hey google, where is my phone" which causes my phone to ring.

HA: Light Bulb Colour Patterns

 IoT devices can usually be controlled from their own app, from Google Home (GH) and Home Assistant (HA), each method has its own features.  I expect the app to have the best level of control, and a subset of that to be available when linked to GH.  HA features are implemented by the community and are typically much better than GH.  For my FCMILA cheapo coloured lightbulb the Tuya / Smart Life app doesn't allow you to do very much.  There is one "scene" called "gorgeous" which displays an pleasing range of colours but it isn't available on GH or HA.  This lead me to investigate the ability to set up HA to display a sequence of colours.

Looking at HA Developer tools/state you can see the current configured parameters for the bulb.  Within Developer Tools/ services you can can configure and test a service to turn the light on with a colour of your choice.

It is now simple to create a script calling this service so that the bulb colour can be changed.  At this stage we want to set up a sequence of colour changes.  It is easier to do this in text mode rather than the user interface.  We simply edit a script which causes a single colour to be displayed and copy/repeat the text for each colour we want.  We change the RGB colour values to  the ones we want and then add a delay action between each section.  We now have a script which displays a sequence of colours, each for 1 second.  Finally we need to add a loop to the script.  Looking at the scripting documentation I setup a "for loop" script in which I can specify how many times the sequence will be displayed.

The completed script can be run from the dashboard or exported to Google Home via Home Assistant cloud so that it can be run with a voice command.