MQTT Basics 

Thanks Daniel. I appreciate the feedback.

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

Thanks for watching!

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

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.

Haha. Nailed it. Thanks for watching.

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

I really appreciate that. Thanks for watching.

Thanks for watching Blake

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.

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.

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

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.

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

@@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.

Thanks for watching Patrick.

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

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.

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.

Thanks for reply. It is helpful

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.

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?

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

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.

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.

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.

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.

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

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

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.

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.

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

Actually the explanation was superb

Thanks Udara.

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