Simple MQTT Client UI using this project

[sukesh-ak]

Lets discuss the requirements for a Simple MQTT Client UI for ESP32-XX Display devices

@mhaberler

[mhaberler]

my goal would be to have generic, small footprint UI support which can can be dropped in as a library or component, not another tasmota or espeasy

let's assume the whole config can be mapped onto a JSON file which is either onboard in nvs or fetched on startup, which includes broker, credentials etc

looking at the broker->UI path I'd see:

1. list of topics to subscribe
2. which LVGL objects/widgets that maps to
3. some way of transmogrifying the incoming message into something which fits with the UI object

1+2 are easy
3: so for example we get

Topic: home/OMG_heltec_ble/BTtoMQTT/DD79C68FBDA2QoS: 0

{"id":"DD:79:C6:8F:BD:A2","mac_type":1,"adv_type":0,"name":"Ruuvi BDA2","manufacturerdata":"9904050858809dfffffec8fc28001c81b681030add79c68fbda2","rssi":-82,"brand":"Ruuvi","model":"RuuviTag","model_id":"RuuviTag_RAWv2","type":"ACEL","track":true,"tempc":10.68,"tempf":51.224,"hum":82.3125,"pres":1155.35,"accx":-0.305967,"accy":-0.964974,"accz":0.027459,"volt":2.637,"tx":4,"mov":129,"seq":778,"mac":"DD:79:C6:8F:BD:A2"}

assume I want to associate "tempc" with a UI label
I can parse the message and extract a key in C++ but thats inflexible which suggests an interpretive step in between

something like JSONata expressions would be cool but that's from nodejs land and not c++

embedding berry would be an option

btw I'd try to keep those parts esp-unaware to the extent possible because they are generic

what do you think?

[mhaberler]

https://forum.squareline.io/t/q-plans-timeline-for-lvgl-9-observer-support/2782

eez-open/studio#311

[mhaberler]

the answers are in:
EEZ Studio: LVGL9 now, observers out of scope
Squareline: LVGL9 per April release, obervers supported later

to leave the choice open, this would suggest not to assume observer support in the UI design tool - matching @kisvegabor 's third option

I did a lvgl8 backport of observers because currently using Squareline (8 only as of now), and it was straightforward - should be safe to go to lvgl9 and play with EEZ Studio meanwhile as Sqareline gets ready for 9

[sukesh-ak]

Squareline studio UI is pretty bad in design specially performance. Not sure what UI framework they are using.
EEZ Studio has pretty good in performance. Though I still like to handcraft UI sometimes so lv_observer is easier for me to include.

[mhaberler]

I think it's Unity

[kisvegabor]

Yes, it's Unity.

[mhaberler]

@sukesh-ak I've been playing with integrating PicoMQTT into my playground

found it to work nicely as a broker fed both with OMG and esp32-ble2mqtt

I think broker + UI is an interesting combination as it can get rid of an external broker in many cases

PicoMQTT is right now MQTT-over-TCP only but should sport Websockets later this spring - can then serve web MQTT clients + publishers as well

ok, it's an Arduino component and as such probably not to your liking, but it might serve as a blueprint for an ESP-IDF component

[sukesh-ak]

Should be able to port it to ESP-IDF without much work. Need to check the license.

I also have a sample here on how to use Arduino library with ESP-IDF
https://github.com/sukesh-ak/Arduino-Library-with-IDF

[mhaberler]

I looked into that, and one part it not quite compatible with pure eventloop operation but I guess @mlesniew might have an opinion?

[mhaberler]

see mlesniew/PicoMQTT#32

[mhaberler]

@mlesniew just solved the issue: mlesniew/PicoMQTT#32 (comment)

[mhaberler]

meanwhile, on the embedded MQTT broker front:

PicoMQTT now also supports MQTT-over-Websockets, opening the path to a web client with say MQTT.js or paho-mqtt

working example

[sukesh-ak]

Several MQTT clients are mentioned in my write-up here including MQTT Web Client.
https://github.com/sukesh-ak/setup-mosquitto-with-docker

[mhaberler]

have a look at adrianromero/myhelloiot#6 (comment)

(can you drop me a private mail or IM contact?)

[sukesh-ak]

My Github profile has my linked-in.
You can reach me => sukesh at yawsoftware.com

[mhaberler]

I think myhelloiot looks like a good set of functionality for generic MQTT dash board:

• several stock widgets (LVGL has enough of those for a start)
• a way to assoicate a widget with a subscription
• a way to extract a value from a structured message
• a way to set the broker (or just use an internal one with PicoMQTT)

anything else? I think that would be pretty useful already