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In the previous lecture, I give you a very quick introduction of notes inside a note, read and learned

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about attributes and a few other things on their own, notes are not very useful.

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They can't do anything in order for them to be useful.

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They need to be connected and configured inside flows.

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So in this lecture, I'm going to show you a few simple examples of notes configured to float to help

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us get started before we go into looking at individual nodes and how those connected and useful in our

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project and in the context of our project.

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To do that, I want to make use of the DHT 22 node that I installed in the previous lecture, and therefore

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I'm going to connect eighteen to twenty two cents to my Raspberry Pi.

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So first I will need to turn off my Raspberry Pi, install the sensor just on a little header, which

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is set up on a little piece of me that I've made and then come back to node read to make use of the

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sensor.

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So here's my note.

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Read Raspberry Pi.

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I'm just going to shut down.

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And hold, right now, I want to gracefully turn off the Raspberry Pi.

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I'm going to go remove power and set up the sensor.

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So I suppose now turned off, I can say there's no activity on the grenade and I'm going to unplug network

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and power and I'm going to take my DHT 22 sensor and just plug it in to head up high.

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And that's all there is to it and to reconnect the network.

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And power.

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And give my reply, a couple of minutes to begin.

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I see no dread it started again.

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Not yet.

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Still trying to reconnect.

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Let's try to refresh the page, it would tell me if the Roseberry prize ready.

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And we're back.

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OK, so let's have a quick look at some examples I'd like to begin with the inject and debug nodes,

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those two together are probably the two simplest nodes.

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So I'm going to connect them simply by wiring them together like this.

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I double click on the inject node.

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You'll see that the inject node allows me to inject a couple of a number of different things to whatever

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node follows it or whatever note it is connected to.

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For now, I'm just going to type in a string called Hellewell with a with their word halo in it and

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click on down.

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So the idea here is that when I click on this button, the word halo, which is in the message that

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will be stored inside in its G payload variable, will be sent over to the next node, can talk more

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about images, thought and physically other types of viable in a dedicated lecture later on in this

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section.

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So that's all there is for this.

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Now, let's go into the payload.

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I'm going to give it a name.

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Just going to say example, debug.

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Node, and you can see that here the output of this node is whatever is inside image or payload, which

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is where Halo is stored and this data payload right now.

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OK, so for this very simple flow to take effect, we need to deploy it so quickly.

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Deploy.

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Successfully deployed and click on the bug button so we can see the messages, you can see that will

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be showing or will be seeing messages from all nodes, you can be more selective if you want.

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You can see right now I clicked on selected nodes and only the single available debug node is showing

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and is, of course, selected.

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Or he can go for current flows.

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You have multiple Smurfs only have one right now.

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So to trigger this flow, I just click on the button here, the tech node, and you can see that I do

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get notification that the trigger was successful.

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And here is the message can change it to something else.

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Let's say I can change this to a timestamp and made a change to my flow.

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So I need to redeploy it, click and deploy button, click on the trigger button for the inject node.

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And this number is actually time.

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Right.

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Click on a link and see how the time.

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Format changes.

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All right.

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Let's go back to the original as a number.

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All right, now let's have a look at another Arsala.

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I'm going to click on this button here to add a new flu.

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Right.

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So this is going to be similar.

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Of course, you can give them names.

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Can you just double click and say this is going to be two example?

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All right, they weren't going to do this.

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I'm going to start with the twenty two, so I'm going to set that up first.

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Right there.

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Double click on it and I'm going to give it a name, DHT 22, I can select the type of sense that it

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is.

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I'm going to make reference to it.

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Terrapin using the PCM chibbaro notation.

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And I know that my senses connected to Chibbaro 17.

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All right, that's it.

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Now on its own.

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It can't do anything.

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I actually have to trigger it, so I have to basically start it manually.

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So there's a couple of ways to do that are probably the easiest way is to use a combination between

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a inject.

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Flu or note, she'd say, which you saw in the first example and then connected to my DHT, twenty two

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cents.

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And of course, I don't want to send a timestamp to my 20 cents.

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I just want to send that a very simple payload, which could be just a number.

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I'm just going to send it something to trigger the D to twenty two to take a reading.

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And that's all there is.

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That's all you need to do here.

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So I'm going to click on OK to get rid of that window.

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And the last thing that I want to do is to output the reading from the sensor to the debug window so

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you know how to do that.

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Right.

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Just use debug node connected through and give it a name, show temperature reading and that's going

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to come from the payload.

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Let's have a look inside here, just in case I think it's all good here, if you want to learn more

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about how to use this particular note, remember, there is documentation actually not here, but here

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there to the documentation for it.

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You can see that the DHT 22 note will store the values from the sensor in the NSG payload variable that

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contains the readings.

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All right.

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So deploy this flu is going to the debug window and then trigger the flu.

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And there you go, there is the the reading nineteen point ninety degrees Celsius.

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Another thing that I'd like to do here is that instead of me having to click on the button to trigger

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it.

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Like the flu itself, the trigger DHEA to reading every, say, 10 seconds, so let's see, there's

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another useful function here or note, I should say, called Trigger, which is right here.

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Have a look at the documentation for Trigger, and it says that when triggered, it can do something

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like send the message right.

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But what is interesting about it is that you can set a period for the trigger so that it can trigger

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whatever follows every few seconds or minutes or even hours.

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So have a look at these properties and you see give them more information about this.

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So the first part is about setting what happens when you activate the trigger for the first time.

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And here we can just set it to center number one.

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Right.

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But then what's interesting for this particular application is that.

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He said, you can respond to the same message every few seconds or milliseconds or minutes or hours.

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So what I'll do first, I will delete this wire and then rewire it via the trigger.

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Note like this.

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I can just rearrange.

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The way that the snow is configured and to then makes it a 10 second intervals.

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Like this, and I give it a name, get a reading.

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Every 10 seconds.

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All right, so let's go back to our debark Windu, redeploy this new flu or updated flu, clean up previous

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blog, previous messages and then click on the button to trigger.

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So here's a first reading and wait for about 10 seconds.

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And here is the second reading, and every 10 seconds after that will be getting a new reading from

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the censor.

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Perfect.

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So there's a very simple flow out while we are edit, you can see that if we're going to the information

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tab and scroll inside the DHT 20 to flow, it's the tab that we're working on right now.

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You can see the nodes that are part of this flow and you can click on each one of those to get the properties

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of each node.

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One of the really nice features of note read is that it really has built in support for documentation.

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I'll show you what I mean.

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Double click on any one of those notes, like this one, for example.

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And then in the edit pane, you'll see that there is a description tab.

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Click on that and you'll see that there is a box where you can type in a document that describes this

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particular note and what it does.

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So this uses markdown so you can format your documentation appropriately.

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It can say something like this.

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What is this note about?

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And you can formatted this a header and you can say this note triggers the 22 Senso.

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Every 10.

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Siggins.

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OK, that's it.

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And now, of course, this documentation appears here for anyone who wants to use it and learn more

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about it, but it's also accessible elsewhere.

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So, for example, here you see down the bottom, you're going to the information tab for the flow.

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You click on the appropriate node and you see down the bottom the documentation appears.

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So you can with a bit of care, you can document your project.

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It really will as you share them with other people.

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I'm going to show you one more very useful feature of node red, which has to do with the ability to

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import and export flows.

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So let's have a look at my node red installation that is running on my Raspberry Pi four.

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And they are I've got this flow.

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So this flow contains, again, an inject note.

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It's got a function node which contains a bit of JavaScript, and then it's got these three debug notes.

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I'd like to export this flow from my Raspberry Pi for and then import them into my Raspberry Pi to.

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So what to do that is to go into the menu up here top right.

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And then say export and that would take the current flow rate.

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And this is the code that describes the contents of this particular flow.

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Right.

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So it's just text.

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I can actually make it format.

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It's just adjacent document.

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And I want to copy this, the clipboard or you can download it in a text file.

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But since I'm working within the browsers now, I can just copy the clipboard.

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Done, then go into my note, read local Raspberry Pi and go for input and I can import from clipboard.

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Paced and I would like to create a new flow based on this slow document or flow definition, go for

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a new flow and import and have a look at this tab.

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It contains my newly imported flow.

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I can just diploid.

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And go to the Dipak window cleaner, previous messages out, actually going to only print out messages

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from the current flow rate and then trigger the flow.

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You go now.

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Well, at this, I just want to share what's happening inside a function notes a double click on that.

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And you'll see that in here we have simple JavaScript.

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I'm creating a little adjacent document, storing it into a local variable and eventually have three

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of those.

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And then I can send those out as an array to the right side of the function through three outputs.

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So because I've got an array with three items in it, I need to configure the output to have three outputs.

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And you can see that I've got one, two, three outputs where this works.

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Is that the first message that you're moving things to the right a little so you can have both the added

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pain and the graphical representation of the node visible?

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So the message one will be available through the first output of the node and message to the second

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and to message three from the third.

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Right.

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Then those messages are captured by the appropriate debug nodes and then print it out and see the first

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debug node is called MSJ one message one and it can see its print out here after a triggered the flow

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and so on.

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I'll be talking more about the functions because functions are of course, extremely powerful.

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Anything you can do with JavaScript, any kind of program you can imagine can go in here to the processing

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for various inputs and then to create appropriate outputs for further down into the flow.

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But this is very useful and I'm going to talk more about the various variables that are available inside

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a flow and inside the entire node rate environment so we can actually share data in between flows,

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not just inside of itself, but in between multiple flows of the same node rate installation.

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OK, so with all that said, let's move on to the next lecture where I'll talk about variables.

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And these are global flow and node variables.