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  • In my last video, I started to use MQTT and a Raspberry Pi as a Broker This week, I got

  • my new Pi zero with Wi-Fi.

  • With this board, there is no excuse to not use MQTT for my projects.

  • So, today, I build a cheapo MQTT broker for under 20 dollars.

  • Look at the length of this video and you see, how easy it is to build one.

  • And you will be astonished, what this little bugger is able to do in addition to broker

  • MQTT messages!

  • So, let’s start: The secret behind the whole thing is Peter

  • Scargill.

  • He is a wizard in small devices and I recommend to check out his blog.

  • Pete produced a Christmas gift for the community: A script, which automatically installs a lot

  • of things on Linux systems, including the Raspberry Pi.

  • You chose, which packets you want and wait for a few minutes or hours.

  • After that, you get your system more or less completely configured.

  • Really great stuff!

  • I wanted to use this script for my new Pi zero, when I read, that Peter was not happy

  • with Raspian on the Pi Zero.

  • It was way too slow for him.

  • Fortunately, he found a better solution: Diet Pi, which can also be used for our project.

  • So, I started with installing dietPi on an SD card, enabled it for my Wi-Fi, and copied

  • Peter’s script to my device.

  • After that, I created two new users, Pi and admin, and started the script.

  • Then, I had to wait for a few hours.

  • Eventually, the script finished, and I had to reboot my Zero.

  • You find the link in the description, if you want to use Peters script for your purposes.

  • To check my newly created system out, I started the Mosquitto broker.

  • It worked.

  • Next, I started Node-Red using the admin user.

  • And it worked, too.

  • Maybe not as fast as I runs on my pi 3, but usable without any problems.

  • When I looked at the available nodes, I discovered, that Peter did completed staff work.

  • He already added many nodes like his famous big-timer, johnny5, pushbullet, some google

  • stuff, raspberry stuff and so on, and so on.

  • This alone is worth many hours of work!

  • And he added also the Node-Red dashboard.

  • So, you get a more-or less complete Node-Red installation.

  • In addition, he added the SQlite database system and phpadmin light for its administration.

  • Absolutely great!

  • There is only one thing I can add here: I made a copy of my SD card and make it available

  • to you for download.

  • This saves you all the hassles of downloading and installing dietpi, and wait for the completion

  • of Peters Script.

  • If you want, you can download and copy this file to a SD card using Win32 Disk Imager,

  • insert the card into your Raspby Pi Zero, connect your Zero to a display and a keyboard

  • and enter your Wi-Fi credentials into the file /etc/network/interfaces.

  • That’s all.

  • And the whole thing did take for sure less than half an hour.

  • If you kept the assigned fixed IP address, you can Putty into a fully configured MQTT

  • broker by connecting to 192.168.0.202.

  • Just for your information, you find these three users on your system:

  • Username Password pi password

  • admin admin For Node-Red root dietpi

  • Of course, you can change the passwords, or add new users, if you wish.

  • Because we saved so many hours, we still have some time left.

  • So, I will build a small data logger for my Sonoff switch using MQTT, Node-Red, and the

  • SQlite data base.

  • From now on, I assume, that you used my SD card image for your Pi Zero.

  • This image contains all material needed.

  • So, first, we test the Mosquitto broker.

  • We could do this by using the built-in functions like mosquitto_sub and mosquitto_pub in the

  • terminal window.

  • But, because we already have Node-Red available, we use this tool to do that.

  • So, we can also check the connection between the two packages.

  • We use theMQTT test flowin Node-Red to do that.

  • First we have to adjust the IP address of the MQTT broker to the address of your Pi

  • zero, if you changed it.

  • This has to be done in these two nodes.

  • In Node-Red, you have todeployafter every change to activate the changes.

  • Now, Node-Red should connect to Mosquitto and you should see the green points here.

  • If we now press this button, a text is published to Mosquitto.

  • And because we subscribed to the all topics, the message comes back from Mosquitto to Node-Red

  • and into our debug window.

  • So, ourHello worldscenario is live.

  • Node-Red and Mosquitto are working together.

  • Cool.

  • Next, we go to theMQTT data Logger Flow”.

  • This scenario needs three main nodes to perform the task.

  • I added two debug nodes to show you, what happens.

  • Let’s start with the MQTT node.

  • This node is subscribed to theRelay topic of our Sonoff device from last video.

  • The next node inserts the topic, the payload, and a timestamp to SQlite.

  • The last node creates the connection to the database.

  • So, Let’s first look at the setup of the database.

  • To do that, we have to connect to phpadminlite.

  • Here, we can manage our database.

  • If you used my image file, you will already find a database called IOT with a few tables.

  • We will only use table Sonoff for this logger.

  • This table has three fields: The topic, a timestamp, and the relay state.

  • If we browse this database, we see, that it is empty.

  • Now, we go back to Node-Red and to the function which creates the SQL statement which inserts

  • a record into the database.

  • I have to confess, I have no idea of Java script and I just used an example and adapted

  • it till it did, what I wanted.

  • So, for sure, there are better ways of doing it.

  • But still, it might be useful for you.

  • The first part creates this line in Node-Red.

  • It shows us, when the last update took place.

  • The next part creates a string called SQL which is filled with an SQL statement.

  • At the end, this string is pushed to the database.

  • If we look at the creation of this string, we seeInsert into Sonoff, which is the

  • table we want to fill.

  • Then, we find all three fields we want to populate.

  • Next, we find the Values, also separated by commas.

  • The string values have to be framed by quotes.

  • If we have a closer look, we see, that we created an ordinary SQL statement.

  • If we go back to our SWL administration, we can execute this statement.

  • And we see the result in the database.

  • The last node does exactly that: It transfers the SQL statement to the database.

  • That’s all.

  • If we now switch the Sonoff of- and on again, we see two additional SQL statements in Node-Red

  • and the two entries in the database.

  • So, our MQTT logger works!

  • Summarized: - We can use our Pi Zero W as a MQTT broker.

  • - If we use dietpi and Peter Scargill’s script, we easily can create such a device.

  • - If you use my pre-fabricated SD card image, you are even faster and you get your broker

  • in less than half an hour.

  • - This broker does not only work as a MQTT broker.

  • It includes also many other pre-installed packets

  • - Because viewers asked me, how to log MQTT data, I used this newly created device to

  • build a simple MQTT messages broker with SQlite - All-in all, it is astonishing what we can

  • get for less than 20 dollars and half an hour of work.

  • It does what we wanted and we even can extend its usage .

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

  • If true, then like.

  • Bye

In my last video, I started to use MQTT and a Raspberry Pi as a Broker This week, I got

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#第126回 Raspberry Zero W / DietPi / MQTTメッセージロガーSQlite / PHPliteAdminの格安MQTTブローカー (#126 Cheap MQTT Broker on Raspberry Zero W / DietPi / MQTT Message Logger SQlite / PHPliteAdmin)

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    Ed に公開 2021 年 01 月 14 日
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