MQTT Basics

QOTD
Do you prefer hot or cold weather?
In this episode I cover the very basics of the MQTT protocol. If you want the straight truth in long form I definitely recommend the following resources from HiveMQ.
www.hivemq.com/...
www.hivemq.com/...
I left out Last Will and Testament but recorded a segment on it that I will put into the next episode because it's pretty much my favorite feature of the protocol and I can't believe I left it out.
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I respond to every single person and love hearing from you.

[@niephasus]

Really useful summary with a simple yet effective example to learn from.

[@KevinSidwar]

Thanks Daniel. I appreciate the feedback.

[@gg-gn3re]

Didn't know the MQTT retain data and send out when another client requests it, that's an interesting thing. Currently just pulling data from a db (using CoAP) and using MQTT for frequent messengers. Cold day for sure, but around 60F is good. you can work outside with a t shirt or no shirt and workup a sweat, but you won't die... and at the same time don't need a bunch of clothes to be warm.

[@KevinSidwar]

I've wanted to spend more time getting familiar with CoAP. Thanks for watching g g.

[@utmostcreator]

how can I set up local broker on my machine and get the url to connect to? using emqx and erlang along with windows 10. and how I can control it, start, stop, restart. Any idea would be appreciated, thank you in advance!

[@KevinSidwar]

Have you looked at this? github.com/emqx/emqx. It shows commands for starting and stopping the service locally and what the requirements are. It looks like the local default url is localhost:18083. To make that available to other devices in your network you'd have to expose that port from your Windows machine using firewall settings. Then other devices should be able to connect to it by IP address or hostname and referencing the 18083 port. Hope that helps.

[@Elpoyoloco1]

What can i do if i want to use this in many homes,and use one broker? As it is now the two guys from the homes can subscribe to eachother topic if they know the name.. help would be much appreciated

[@KevinSidwar]

There are hosted broker options where, yes, both homes would speak to the same broker and could therefore be aware and react to things happening in both locations.

[@Elpoyoloco1]

@@KevinSidwar the thing is i have set up my own broker in aws free tier :) but i cant install any auth-plugin for authentication...

[@KevinSidwar]

@@Elpoyoloco1 Oh bummer. Sorry, I haven't ever gone through the process of hosting my own broker in AWS so I'm not sure what all of the pieces are to get that working.

[@Electromaniaworld]

first time understood what is mqtt. thanks.

[@KevinSidwar]

Thanks for watching!

[@akbarnandyalampeta839]

I have configured MQTT in my current Project, by using MQ Explorer, when I m connected MQTT Client Utility - then only the messages coming to the TOPIC is getting subscribed, once the MQTT Client Utility gets disconnected, no messages coming to the topic, and they are not getting subscribedPlease help me on this question

[@KevinSidwar]

Hey Akbar, thanks for watching. I don't have any experience with IBM's MQTT stuff like Explorer and the Client Utility. Can you describe your setup more? From what I've been able to read the client utility is used to test a setup and can publish to topics and subscribe to other topics. If the client gets connected then it makes sense that you wouldn't see messages anymore. Can you explain the problem a bit more?

[@volkangundogdu1008]

very natural way of explaining, your quick solutions i.e : white board so cool :)

[@KevinSidwar]

Thanks Volkan. I really appreciate you watching and big shout out to Denmark.

[@volkangundogdu1008]

I really liked the way you explained the concept though I am a bit new to subject I got good insight. And I felt that more after I watched other videos where mqtt and coap is explained.

[@freeelectron8261]

Exercise for nerds - go to the back shed and pull out a bigger whiteboard :) Thanks for the lecture on MQTT

[@KevinSidwar]

Haha. Nailed it. Thanks for watching.

[@fouzaialaa7962]

can mqtt work with lora modules ??? i need long range and wifi doesn't cut it

[@KevinSidwar]

Yes and no. So MQTT is built on TCP so out of the box it's not well suited for LoRa and I'm not aware of any LoRa modules that will work with it out of the box. However, a common approach is to have a LoRa gateway have an MQTT connection. Something like a Raspberry Pi that has a LoRa radio attached and can received messages from LoRa devices. The Pi can then publish the messages over MQTT or receive subscribed topics and forward them to the individual devices over the LoRa connection. Hopefully that helps.

[@lbs4you]

I prefer summertime and heat.

[@KevinSidwar]

Thanks for watching Tommy and for answering the question of the day. Have an awesome week.

[@harshaltetambe9793]

hi Kevin. I have seen the video it is nice . i have one question - Had you implemented MQTT protocol with GSM module?

[@KevinSidwar]

I have not implemented MQTT via GSM. I wonder if something like this would be helpful for you. www.raviyp.com/embedded/226-mqtt-protocol-tutorial-using-sim900-sim800-modules-mqtt-over-tcp

[@MaxGoddur]

This might be slightly off topic but have to ask the question and it is: Is ESP8266 and NodeMCU one and the same? Hear them tossed about on lots of videos but following their instructions and some of these are great videos, I don't get the same results.

[@KevinSidwar]

Great question. As far as I understand it the ESP8266 is an all in one WiFi chip that can also run custom firmware. The NodeMCU is based on the ESP8266 but so are lots of other things. I'm not sure how the various offerings differ.

[@bryanwarman]

ESP8266 is essentially the wifi chip that is a part of the NodeMCU micro-controller board. It enables that board to work wirelessly. It's comparable to a Wemos D1 Mini. It's analogous to the various different Android phones. They're all running the same OS (in the case of the NodeMCU it's the wifi chip and not the OS) but they're made by different companies and have different features.

[@owensoft]

Cloud providers don't want to ensure any high QOS unless you pay for a higher tier service

[@KevinSidwar]

Yeah, it's definitely higher cost to them and some, like Microsoft and Amazon, just don't offer it in their IoT offerings at all which surprised me. Even if it's some ridiculous cost I thought they'd offer it.

[@msmadaram]

have you ever work on android broker such as moquette or something like that ?

[@kevinmalott]

Very helpful. Thanks.

[@KevinSidwar]

Thanks Kevin and thanks a bunch for watching. Have a great week.

[@urtra]

You do great work !!!! Thanks

[@KevinSidwar]

I really appreciate that. Thanks for watching.

[@suyashjain9972]

Hi , Super explaination !! one question How client will identify the exact topic name to which he want to subsribe to ? Is there any way for client to query broker to get list of topics

[@KevinSidwar]

Hey Suyash, thanks for watching. I'm not aware of a way to query the broker for all topics. The broker is really just a pass through for all nodes to subscribe and publish through. Normally in MQTT you know exactly which topics you want to subscribe to. It's not really meant to be a discoverable system as far as I know. Sorry that's not more helpful.

[@suyashjain9972]

Thanks for reply. It is helpful

[@BlakeEdwards333]

Thanks for the vid!

[@KevinSidwar]

Thanks for watching Blake

[@freeelectron8261]

Good Intro to MQTT - thanks! I like cooler weather - hot days knock me around.

[@rahulswami7754]

It's really great video ..... My query is.. 1- Do we get any response or ACK from server to publisher side? 2- can we use any broker (mosquitto, Paho) to communicate with cloud/server.

[@kalineb.fmesquita6346]

2. Yes, it's possible to use brokers to communicate with cloud/server. Mosquitto can be used in raspberry Pi and it's easy to implement.

[@bayomiller3415]

Hello, i am totally new to MqTT, my question is; is QOS 1 the best ?

[@KevinSidwar]

Hey Bayo, thanks for watching. Great question. There isn't really a "best" QoS as a blanket statement. It really depends on what the application is and even what types of nodes are involved. It sounds good to say I want to guarantee at least one delivery of the message but there is overhead involved on the client end in having to ACK (acknowledge) receipt. In an extremely low power sensor application you may not want that extra response being sent by the client as it will eat into your battery life. You may be fine missing a message here and there so QoS 0 may be best in that scenario. For example, maybe a small e-paper display is subscribing to sensor topics and displaying those values. It runs on battery and displays the latest readings for temp and humidity in your shed. It would be ok to miss an update here and there to extend the battery life. It likely would run entirely on retained messages as it wakes up every so often to get readings. QoS 0 would be fine here. However, you may decide that a similar display showing your BBQ meat temperature can't afford to miss a reading so QoS 1 would be best. Going to the extreme you may have a piece of medical equipment that administers a dosage of some drug (terrible idea with MQTT but just for fun let's go with it). It administers said dosage upon receipt of a message. Here QoS 2 would be required to ensure the dosage is delivered once and exactly once. Hopefully that makes sense and helps paint a better picture. Thanks again for watching.

[@bayomiller3415]

please is this all about Mqtt? if there is more can you help me with a table of content i can use to proceed? thanks for your assistance.

[@KevinSidwar]

An excellent resource for all things MQTT is www.hivemq.com/mqtt-essentials/

[@bayomiller3415]

Hello again! i appreciate your regular response. please can you help me with a list of equipment on how to set up MQTT, if you can give me a mail we could use to communicate i will be glad. i will really like you to mentor me on this topic. Thanks once again

[@KevinSidwar]

Hey Bayo, there is not specific equipment list for MQTT. Any device that can do TCP communication can likely handle MQTT so really almost any IoT platform could be used. Here are a couple of Hackster.io projects you could use to follow along. www.hackster.io/anasdalintakam/mqtt-publish-subscribe-using-rpi-esp-and-photon-864fe9 www.hackster.io/techiesms/mqtt-esp8266-12e-nodemcu-157e8b You're welcome to reach out via email kevin at sidwar dot com.

[@volkangundogdu1008]

in denmark hot weather is always appreciated..

[@cangrejojeringa]

cold for me please...

[@patrickrobinson317]

Thanks !!!

[@KevinSidwar]

Thanks for watching Patrick.

[@MaxGoddur]

Hot or Cold? For me, it is a no brainer the cold. I was in east Texas for an extended stay and could not understand how the people got things done. I don't get cold that easily but the down side is my wife is the exact opposite. She can get into the car on a hot day and delay rolling down the windows for 5 or 10 minutes. It really is a struggle for climate control in our house. When will the code for the trinket be available? Oh, and my RFM69's are on their way funny, thought I ordered them and received them but can't find them.

[@KevinSidwar]

Trinket code should be up by this weekend. I'll make sure you get a link.

[@hassanlaghbi7047]

Nice

[@mkd12345678]

Thanks for the vid. No shoutouts to GaryVee? 😂

[@rafaelmarroquin4429]

excelente explicacion :) Le falta una Rpi para hacer un ejercicio practico y quisas un ESP8266 :D

[@KevinSidwar]

Hola Rafael. Gracias por la observacion y gracias por ver. Si tuviera tiempo haria un ejemplo pero estoy gastando todo el tiempo con el proyecto disco de hockey. Espero que todo este bien con usted y gracias otra vez.

[@MrBobWareham]

Just too complicated for me

[@KevinSidwar]

Sorry the explanation wasn't more clear Bob. Happy to try to answer any questions you might have.

[@wlondoner]

Actually the explanation was superb

[@Electromaniaworld]

may be my channel might be interesting for you

[@udarakasun]

very usful

[@KevinSidwar]

Thanks Udara.

[@platoboy]

depends how big my ass is at the time

[@platoboy]

Hot vs Cold...