Electronics > Beginners
IoT Hardware
csheldon:
Dear all,
I am starting to explore some IoT concepts and architectures both regarding SW and HW. Since I am beginning with all of this, there is really large amount of information
that I would really like to put to its place. I would appreciate if someone with knowledge and experience can answer a couple of (maybe stupid) begginner questions.
First let's begin with HW:
I've noticed good ammount of RFM69 RF-to-mqtt gateways.
1) Can somebody please explain how these work and what is the purpose of having RF-to-MQTT gateway?
2) How does the ESP8266 fit into all of this? (for example there are ESP32's and ESP8266's packed with RFM69 on same board)
3) What is the purpose of ESP8266 in such gateway (transciever)
There are also some RFM2PI boards with rfm69 and atmega chips that attach to RaspberryPi, so:
1) What is the idea behind this?
2) What job RPi does in such cases? What is it used for?
3) Can it replace the above ESP8266 + RFM69C concept or both concepts have their own purpose?
Regarding the IoT SW arhitecture:
1) Can somebody please explain the idea behind MQTT, Node-Red and how all this SW arhitecture fits in to two of the above mentioned concepts.
2) What OS does Rpi need to have in order to be deployed as MQTT broker?
Naguissa:
--- Quote from: csheldon on September 18, 2018, 06:32:45 pm ---1) Can somebody please explain the idea behind MQTT, Node-Red and how all this SW arhitecture fits in to two of the above mentioned concepts.
--- End quote ---
MQTT: A simple message protocol. Using a server you can connect several clients and all are connected.
Node-Red: Tool that produces JavaScript code able to run using Node.js
SW: In the end, you can use watever you want. For experimenting, I've used PHP + MongoDB + MQTT (only for user identification on MQTT, using same users as PHP page) here: https://www.foroelectro.net/arduino/en/mqtt-doc (sorry, I just noted that english translation is not done)
--- Quote from: csheldon on September 18, 2018, 06:32:45 pm ---2) What OS does Rpi need to have in order to be deployed as MQTT broker?
--- End quote ---
The Linux flavor you are best comfortable with....
rjp:
--- Quote from: csheldon on September 18, 2018, 06:32:45 pm ---Dear all,
I am starting to explore some IoT concepts and architectures both regarding SW and HW. Since I am beginning with all of this, there is really large amount of information
that I would really like to put to its place. I would appreciate if someone with knowledge and experience can answer a couple of (maybe stupid) begginner questions.
First let's begin with HW:
I've noticed good ammount of RFM69 RF-to-mqtt gateways.
1) Can somebody please explain how these work and what is the purpose of having RF-to-MQTT gateway?
2) How does the ESP8266 fit into all of this? (for example there are ESP32's and ESP8266's packed with RFM69 on same board)
3) What is the purpose of ESP8266 in such gateway (transciever)
There are also some RFM2PI boards with rfm69 and atmega chips that attach to RaspberryPi, so:
1) What is the idea behind this?
2) What job RPi does in such cases? What is it used for?
3) Can it replace the above ESP8266 + RFM69C concept or both concepts have their own purpose?
Regarding the IoT SW arhitecture:
1) Can somebody please explain the idea behind MQTT, Node-Red and how all this SW arhitecture fits in to two of the above mentioned concepts.
2) What OS does Rpi need to have in order to be deployed as MQTT broker?
--- End quote ---
1.1) ultra low power LoRa radios need to get their data onto the network, the gateway does this
1.2/3) the esp8266 handles the mqtt over wifi bit and can communicate with sensors or LoRa radios via its GPIO's
2) same stuff but having an rpi with LoRa radio doing the gateway work instead of the ESP module
3) MQTT is a way of seperating producers from consumers - you have devices and sensors providing new data events on the network and then you can have multiple listeners recording/reacting to those events.
many will argue you can use http rpc or custom udp servers instead of MQTT but you then need to replicate the multiple listener feature and thats not as simple as it seems.
multiple listeners means you can have one stable daemon recording the data that never gets touched.
then you have other listeners doing screen displays or alarm events, all seperate to each other without over loading the one program with too many features that make it slow or unstable.
it allows you to isolate all the features of your IOT app from each other and things that are stable can stay stable.
you can also then have the MQTT brokers push events out across different networks (bridging) and build complicated public/private scenarios.
iainwhite:
Adafruit has a basic tutorial here.
csheldon:
--- Quote from: iainwhite on September 19, 2018, 03:31:42 pm ---Adafruit has a basic tutorial here.
--- End quote ---
Thanks everyone for all your answers, Let+s clarify them a bit more please..
Still haven't undestood whats the idea of RFM69 RF to MQTT gateway...
Let's put things this way:
In no specific order, I have a:
1) small sensor node with 8-bit atmel and RFM69 on board (for RF to MQTT function), lets say it's measuring temperature (https://harizanov.com/wiki/wiki-home/funky/)
2) RF69CW receiver board, something like RFM2PI? (https://wiki.openenergymonitor.org/index.php/RFM12Pi_V2)
3) Raspberry Pi
4) ESP32/ESP8266 with onboard RFM69 (https://harizanov.com/2015/11/rfm69-to-mqtt-gateway-using-esp8266/)
Can somebody describe the example use-case of all of these devices and what is their purpose in that particular hypotethical example.
Also questions:
1) Can ESP32/ESP8266 replace RPi+RFM2Pi , if not, can you please describe what are their respective functions
2) In a case where we have multiple small sensor nodes with RFM69. How can multiple RFM nodes communicate to single reciever? Do they use time division multiplex or some kind of an CSMA/CA..
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