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

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

  • Thebrainsof 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,

  • and two Sonoff switches.

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

  • setup.

  • 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.

  • I did this in video #126.

  • I even posted an image for a Pi Zero.

  • You find a link in the description.

  • So, you have an easy start.

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

  • of Peter.

  • You find a link in the description.

  • So, we have now a working MQTT broker.

  • With the utilityDietPi-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.

  • It runs without any problems.

  • 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 likerelayoralexa”.

  • 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

  • see a lot of messages coming.

  • Each message has a topic and a payload.

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

  • We can nowsubscribeto particular topics usingmosquito-subplus the desired

  • topic.

  • 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.

  • We start node-red on our Pi.

  • 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.

  • But how do you get this flow?

  • This is really easy.

  • You go to my Github and open the fileflow.txtwith 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.

  • Hit import and the miracle happens.

  • You have exactly my flow on your computer.

  • Cool.

  • BTW.

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

  • Now we start from left to right.

  • The first node is a so called MQTT node.

  • You see this if you compare the color and the symbol with thepaletteon the left.

  • You see also, that it is aninput 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

  • port is 1883.

  • 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, “doneand deploy.

  • Connected to this node is a so-calleddebug 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.

  • Now, we see the topic and the payload.

  • “0” payload meansoffand “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-calledfunctionnode.

  • I use the trigger node for our purpose.

  • This has the desired function: It sends anonmessage to its output as soon as

  • it gets any message at its input.

  • After 5 minutes, it automatically sends anoffmessage.

  • We also select re-trigger.

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

  • If we want, that only on messages reach ourPulsenode, we can filter them with

  • a switch node.

  • Here, I define, that I only want theonmessages forwarded.

  • The off messages are suppressed.

  • 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.

  • So, I added an audio output.

  • In several languages, of course!

  • Now, I can concentrate on my work and get acoustic feedback.

  • How cool is that?

  • BTW, you can look at these nodes if you are interested on how you can achieve this function.

  • We could connect the output of the pulse node directly to our LIGHT_Main node.

  • LIGHT_Main, by the way, is also an MQTT node, this time an output node.

  • And its topic is the topic of the Sonoff to switch the light on.

  • But, we want more: We want, that we are able to override the PIR sensors with either a

  • dashboard or with Alexa.

  • So, we introduce a new input node: A dashboard button node.

  • Its function is simple: It creates orinjects” a 1 for on, a 0 for off, and a “A” for

  • automatic.

  • But is not operated from this page.

  • If we go back to our main page and selectNode Red UI Desktop”, we get a new window.

  • Here, we see for each of the nodes a button with a label.

  • I also grouped the different buttons according their purpose.

  • So, I have now a smallcommand center”.

  • But now, we have two different chains of command for our Sonoff switches: The PIR signals and

  • the signals from our Dashboard.

  • It is quite obvious, how this should work: If we press the on or off button on the dashboard,

  • we want, that the lamp is on or off, even if a conflicting signal comes from the PIR

  • sensor.

  • Only if it is onAutomatic”, we want, that the signal is transferred directly from

  • ourPulsenode to the Lamp.

  • But how can we achieve this?

  • Here, we need a few things: We have to use a fully programmable node, and we have also

  • to have variables which can store a particular status.

  • The first is easy: We just take the emptyfunctionnode.

  • This node is programmable in java script.

  • So, let’s have a closer look.

  • If we look at a new node, we just see, that it returns the message it gets.

  • So, we learn two things: 1.

  • The full message on the input is called msg and

  • 2.

  • We can transfer a message to the output byreturningit.

  • Simple.

  • Now, let’s look at such a message.

  • To do that, we use our PIR sensor and the debug node.

  • The only thing we do is, to select the complete message.

  • Then, we see anobject”, and its content, which we easily refer to.

  • You will later see, how.

  • To play with that setup, I place the function node between the PIR sensor and the debug

  • node.

  • So, if we want to refer to the topic, we use msg.topic.

  • So, if we want to transfer the topic also to the payload, we just write this small code.

  • And if we test now, we see in the debug tab, that the magic works.

  • But very often, the debug tab is clouded by many different messages.

  • We have to find a better way.

  • What, if we could see important info in proximity to the node, like with the pulse sensor?

  • Easy, if you know, how.

  • We just add this line of code, and we now see the payload directly in our flow.

  • Nice.

  • But how do we get thisoverridebehavior?

  • Here, we can add a few lines of code: If theoverridevariable isONwe want,

  • that the payload always is “1”, and ifOFF”, it has to be “0”.

  • If the variable isauto”, we transfer the payload without change from the input

  • to the output.

  • So, we have to find a way to set and store the override flag.

  • So far, we only had messages to work with.

  • If the next message arrives, we lose the content of the former.

  • If we look at our override node, we get sometimes a message from thealways onbutton,

  • or from the PIR sensor and so on.

  • To achieve our goal, we have to store the override flag every time a message from the

  • dashboard arrives.

  • And the override flag should not be affected by the messages from the PIR sensor.

  • These lines of code do exactly that.

  • Our dashboard buttons all include the wordOVERRIDEin their topic.

  • So, we filter these messages and set the override flag accordingly.

  • If we now test our setup, it behaves exactly as desired.

  • We can use Alexa to switch the lamp on or off, even if the PIR sensor is still on.

  • We could now go on to the next topic.

  • But I do not want to omit telling you, that Peter Scargill wrote a small article about

  • variables in node-red.

  • You can, for example, store global variables in one place and use them in another.

  • If we store the result of the override flag in a global variable, we can use it in our

  • second node.

  • We will use this function in our data logger.

  • From our previous videos, we know, that Peter’s script also installed the SQLite database.

  • Here, we want to store all events from the two PIR sensors, together with the override

  • flags.

  • For that, we go to the main page and from there, to SQLite administrator.

  • Here, we create a database called Sonoff and add four fields: Topic, payload, timestamp,

  • overrideMain, and overrideTable.

  • That is all here.

  • We go back to our node red tab and start with connecting the two PIR sensors to a function

  • node.

  • This function node is connected to a SQLite node.

  • Now, our function node gets all messages from the two PIR sensors.

  • Now, we just have to bring all into a form in which the SQLite node will store it properly

  • away.

  • In my last video, I showed you one version to do that.

  • Some of my viewers made a point, that this method is not very secure.

  • So, this time, I use a different method and hope, it is better.

  • The SQLite node needs a “SQL statement as a topic and the field content as a payload.

  • So, the SQL statement isINSERT INTO Sonoffand all fields of the database.

  • At the end, we add a “VALUEStemplate with the same number of question marks.

  • And the payload contains the content of the variables in the right order.

  • The rest of the code is easily understandable.

  • It only formats the time stamp in a “human readable format”.

  • And, of course, displays the last update time as a reference below the node.

  • Now, everything is done and we can deploy the flow a last time.

  • If you want to create a backup, you can export the whole content or only selected nodes into

  • your clipboard.

  • Then, you paste it in a text file and you are done.

  • Very simple, too.

  • And, if you want to know how much resources node red uses, you go back to the main page,

  • and toWeb Administrator”.

  • Here, you can do all the small stuff an administrator has to do.

  • So, summarized, we are able to control our two lamps by two

  • PIR sensors can override their signal by either pressing

  • a button on a dashboard or by calling Alexa Were able to use voice as an output

  • were able to store a nice log in a structured database.

  • And we even learned a few lines of java script.

  • For me, I see now in the morning, if my PIR sensors were triggered during night.

  • Then, the usual suspect would be our cat called Dishka.

  • fortunately, we did not name herAlexa”.

  • I hope, this video was useful or at least interesting.

  • If true, then Like.

  • Bye

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

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#ホームオートメーションのための128のノードレッドトリック(JS、オーディオ、SQlite、Alexa、Mosquitto MQTTなど)を紹介します。 (#128 Node-Red Tricks for Home Automation (JS, Audio, SQlite, Alexa, Mosquitto MQTT etc.))

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    Ed に公開 2021 年 01 月 14 日
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