Name: #128 Node-Red Tricks for Home Automation (JS, Audio, SQlite, Alexa, Mosquitto MQTT etc.)
Uploaded: 2017-05-19T04:06:50.000Z
Duration: 17 min 37 s
Description: Thousands of YouTube videos with English-Chinese subtitles! Now you can learn to understand native speakers, expand your vocabulary, and improve your pronunciation...

Last week we started with our home automation system based on PIR sensors and Sonoff Switches.

Basic passive voice

Both devices were operated by a Firmware based on Tinkerman’s Espurna framework.

The “brains” of the system is a Raspberry Pi zero and a script provided by Peter Scargill.

And all communication is done via the MQTT protocol.

Today, we will bring these things together and dig a little into node-red and SQLite.

I will also show you, how you can monitor your Pi Zero from a web interface.

So, let’s start: You remember, I have 2 PIR sensors, one Alexa,

This is just a small setup, but we can learn a lot which can be used if we extend this

Last week, we were able to send messages to a public MQTT broker.

Because we do not want to leave our secure Wi-Fi network, we first setup our own MQTT

broker on a Raspberry Pi behind our Firewall.

If you want to use another Raspberry, you have to install Raspbian and run the script

With the utility “DietPi-setup”, we can give it a fixed IP address.

You can also work with the name of your device, but, I decided for a fixed address.

I also decided to use my old Pi zero without Wi-Fi, because I will place the device close

to my switch and I am able to connect it to a Ethernet cable.

For that, I purchased a 3$ USB hub with Ethernet connection.

I even can insert the Keyboard in one of the three USB plugs if I want.

So, The IP address is 192.168.0.203 and its name is hub.local.

Next, we have to change the MQTT broker addresses in our PIR sensors and our Sonoff switches.

This can be done by the webinterface introduced in Video #127.

Here, we are also able to set the first part of the topics string.

The device will automatically insert its board name and add things like “relay” or “alexa”.

For the moment, I do not use username/password for MQTT.

Now, we can start MQTT with the command mosquito -v. When we power our devices, we should now

This is, because the devices publish many different topics to the MQTT broker.

We can now “subscribe” to particular topics using “mosquito-sub” plus the desired

Now, we only see the messages of this topic.

If you use my SD card image, you have to issue two additional commands now.

Otherwise, later-on, you will see an empty page.

Now, we know, that the broker runs and we can go on to the next step.

As soon as it runs, we can connect to it from a browser by calling the address of our raspberry.

Just type the IP address in a browser window and you get this nice menu.

For the next step, we go to node-red control panel.

If there is already something there, you can delete it.

For this video, we start with a fresh Flow.

You go to my Github and open the file “flow.txt” with any editor.

Then, you select the whole text and copy it with crtl-c.

Next, you go to node-red and import from clipboard.

Paste the content of your clipboard and decide, if you want a new flow.

You have exactly my flow on your computer.

You can do this with all sorts of objects you find in the internet.

You see this if you compare the color and the symbol with the “palette” on the left.

You see also, that it is an “input node”.

Next, we have to connect this input node with our MQTT broker.

Easy: Because we run on the same computer, we just type-in localhost and the Mosquitto

Fortunately, we only have to enter this once and can refer later to it.

Because this node should connect to the main PIR sensor, we have to select the right topic.

The client id and the other tabs are not important for the moment.

If you are interested in these, you can watch my video #125.

If you do not remember the topics, just enter # as topic, “done” and deploy.

Connected to this node is a so-called “debug node”.

This node sends messages to the debug window.

We can define, how much info we want and we can switch it on or off.

“0” payload means “off” and “1” means on.

This is defined by the firmware of our PIR sensor.

So, the connection to our PIR sensor works.

Next, I want, that the lamps keep on for 5 minutes after my last movement.

This is to prevent, that the light goes on-and off if I am thinking…

To achieve that, we can choose a so-called “function” node.

This has the desired function: It sends an “on” message to its output as soon as

After 5 minutes, it automatically sends an “off” message.

As we have seen before, the PIR sensor sends on and off messages.

If we want, that only on messages reach our “Pulse” node, we can filter them with

Here, I define, that I only want the “on” messages forwarded.

I could add a second output for the off messages…

The pulse node has a nice feature: it shows us its status with a blue dot.

Later on, we will build such a feature for our own nodes.

Another nice feature is the sound node: It helps for example during debugging, when you

work with your sensor and you cannot monitor node red at the same time.

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#128 Node-Red Tricks for Home Automation (JS, Audio, SQlite, Alexa, Mosquitto MQTT etc.)

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