#18 Raspberry Pi: Install and Test Mosquitto MQTT Broker on Raspberry Pi 3 (Raspbian Stretch OS) | APDaga Tech

IoT Tutorial #18 [ Raspberry Pi Tutorials #6 ]

In previous post,
we have used https://www.pubnub.com as a Broker for Publish -Subscribe IoT Architecture.

Now we will be use Raspberry Pi 3 as a broker.

For Publish-Subscribe IoT Architecture, we need :

• Client (Publisher and Subscriber)
• Broker (Server)

Recommended Internet of Things (IOT) Courses:

1. Udemy: Complete Guide to Build IOT Things from Scratch to Market
2. LinkedIn: IoT Foundations: Fundamentals
3. edX: Introduction to the Internet of Things (IoT)
4. edureka: IoT Certification Training on Azure
5. Coursera: An Introduction to Programming the Internet of Things (IOT) Specialization
6. Eduonix: Internet Of Things (IOT) Bundle

MQTT (MQ Telemetry Transport) is one of the widely used protocol for Publish-Subscribe IoT Architecture.

In order to use Raspberry Pi 3 as Broker (Server), we need to install (MQTT) moquitto server
and To use Raspberry Pi 3 as client (Publisher or Subscriber), we need to istall (MQTT) mosquitto client on RPi3.

Follow these steps sequentially, to Install (MQTT) moquitto server and client on RPi3 (Raspbian Stretch OS):

STEPS:

1.      Installing MQTT Broker on Raspberry Pi:       

Open terminal on RPi3 and Run following commands sequentially:

#1.  To change directory to home directory

cd ~

#2.  To Download/Fetch the the mosquitto repository key (file)

sudo wget http://repo.mosquitto.org/debian/mosquitto-repo.gpg.key

#3.  Set this key

sudo apt-key add mosquitto-repo.gpg.key

#4.  Change directory to below path

cd /etc/apt/sources.list.d/

#5.  To Download/Fetch mosquitto strech list

sudo wget http://repo.mosquitto.org/debian/mosquitto-stretch.list
sudo wget http://repo.mosquitto.org/debian/mosquitto-wheezy.list

#6.  To update all

sudo apt-get update

#7.  To change directory to home directory

cd ~

#8.  To Dwonload/Fetch openssl

sudo wget http://security.debian.org/debian-security/pool/updates/main/o/openssl/libssl1.0.0_1.0.1t-1+deb8u7_armhf.deb

Note: If you get any "404 not found" error in wget command, then put the link given in the command in the browser and check for the updated/latest version for the same package and use that (update) link in wget command.

#9.  To install downloaded bebian package

sudo dpkg -i libssl1.0.0_1.0.1t-1+deb8u7_armhf.deb

#10.  To Download/Fetch web socket library

sudo wget http://ftp.nz.debian.org/debian/pool/main/libw/libwebsockets/libwebsockets3_1.2.2-1_armhf.deb

Note: If you get any "404 not found" error in wget command, then put the link given in the command in the browser and check for the updated/latest version for the same package and use that (update) link in wget command.

#11.  To install downloaded debian package

sudo dpkg -i libwebsockets3_1.2.2-1_armhf.deb

#12.  To install mosquito

sudo apt-get install mosquitto

#13.  To install mosquitto clients

sudo apt-get install mosquitto mosquitto-clients

For better understanding, watch the video below:

Demonstration:

     

         2.      Test installed mosquitto (MQTT broker):

#1.  Start mosquitto (MQTT broker) as a service

sudo /etc/init.d/mosquitto start

#Expected Response:

[ ok ] Starting mosquitto (via systemctl): mosquitto.service.

#2.  Start Subscriber for topic_name "iot"

mosquitto_sub -d -t "iot"

Note: -d : debug mode, -t : topic_name

#Expected Response:

Client mosqsub|2917-raspberryp sending CONNECT
Client mosqsub|2917-raspberryp received CONNACK
Client mosqsub|2917-raspberryp sending SUBSCRIBE (Mid: 1, Topic: iot, QoS: 0)
Client mosqsub|2917-raspberryp received SUBACK
Subscribed (mid: 1): 0

#3.  Start Publisher for topic_name "iot" and send message:
#Open new terminal window (keep previous terminal window open):

mosquitto_pub -d -t "iot" -m "Hi, This is my msg..."

Note: -d : debug mode, -t : topic_name

#Expected Response: (On Publisher Window)

Client mosqpub|2933-raspberryp sending CONNECT
Client mosqpub|2933-raspberryp received CONNACK
Client mosqpub|2933-raspberryp sending PUBLISH (d0, q0, r0, m1, 'iot', ... (21 bytes))
Client mosqpub|2933-raspberryp sending DISCONNECT

#Expected Response: (On Subscriber Window)

Client mosqsub|2917-raspberryp received PUBLISH (d0, q0, r0, m0, 'iot', ... (21 bytes))
Hi, This is my msg...

Here, Message we published using PUBLISHER is received by SUBSCRIBER.

That means, Testing of the mosquitto MQTT broker completed Successfully.

3.      Installing mosquitto MQTT Client on Computer: 

#1.  To install mosquitto MQTT client on laptop (Windows / Mac / Linux etc): 

For MacBook:Open terminal on macOS and paste these commands sequentially:

/usr/bin/ruby -e "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install)"

brew install wget

For Others: To install mosquitto MQTT client on laptop (Windows / Linux , etc)Visit here: https://mosquitto.org/download/

#2.  Start Subscriber for topic_name "iot" and to connect to MQTT Broker (RPi3):

For Macbook:

mosquitto_sub -h 192.168.0.35 -t "iot"

Note:
-h : host = <ip_address_of_RPi3>
 -t : topic name

Now whatever message is sent to the RPi3 (MQTT Broker) with topic name "iot" by any publisher will be received by your computer (MQTT Subscriber)

4.      Stop the MQTT Broker on Raspberry Pi:      

Open terminal on RPi3 and Run following commands sequentially:

#1.  Stop mosquitto (MQTT broker) service

sudo /etc/init.d/mosquitto stop

#Expected Response:

[ ok ] Stopping mosquitto (via systemctl): mosquitto.service.

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Click here to see more codes for Raspberry Pi 3 and similar Family.

&
Click here to see more codes for NodeMCU ESP8266 and similar Family.
&
Click here to see more codes for Arduino Mega (ATMega 2560) and similar Family.

Feel free to ask doubts in the comment section. I will try my best to solve it.

If you find this helpful by any mean like, comment and share the post.

This is the simplest way to encourage me to keep doing such work.

Thanks and Regards,

-Akshay P. Daga