@lbuque Thanks a million to You, I finally got the code working! Looks like the thing I was missing was to use "MQTT apply for messaging" block in the loop. And changing the default 0 keepalive value (after some searching I found it caused problems with my Mosquitto broker).

MQTT topic subscribe still seems to be not working in Alpha 16 - no error but no activity on message receiving either. Anyone else has the same issue?

Somehow I managed to link S3 devices to my account by flashing Alpha-9 version of UIFlow firmware, instead of the newest one.

@ajb2k3 Thank You for the video, however when showing how to get the API key about getting the API key I noticed only "On the bottom here is where you would normally select but as you can see it's already connected" and "I'll explain how to get that on a later video". Do You have the link to that "later video" as well?

@felmue Thank You, after I changed the code via Thonny and moved mqtt_client.subscribe after initialization the error disappeared. However the device still does not react to MQTT topics it has subscribed. So the bug is not only in UIFlow2 (incorrectly placed subscribe call) but also in MQTT library or firmware?

@ajb2k3In that case, is there an option to use UIFlow with S3 while UIFlow2 is "for testing only"? I did not see any warnings saying "things will not work" while buying it. Is there any timeframe when the already enabled functionality might work? I'm currently not asking about new features or support for more hardware, just for the things that already are available in UI.

Hardware used is Atom S3, software - UiFlow2.
My UiFlow2 code:

Without "MQTT subscribe" block all else works.
Error when running on device:

Python code generated by UiFlow:

import os, sys, io
import M5
from M5 import *
from umqtt import *

circle0 = None
mqtt_client = None

def mqtt_mqttDebugIncoming_event(data):
global circle0, mqtt_client
circle0.setColor(color=0x009900, fill_c=0x009900)

def setup():
global circle0, mqtt_client
mqtt_client.subscribe('mqttDebugIncoming', mqtt_mqttDebugIncoming_event, qos=0)

M5.begin()
circle0 = Widgets.Circle(62, 62, 50, 0xffffff, 0xffffff)

mqtt_client = MQTTClient('mqttDebug', 'homeassistant.local', port=1883, user='mqttdebug', password='mqttdebug', keepalive=300)
mqtt_client.connect(clean_session=True)
mqtt_client.publish('mqttDebugOutgoing', 'This works, broker receives message!', qos=0)
circle0.setColor(color=0x3333ff, fill_c=0x3333ff)

def loop():
global circle0, mqtt_client
M5.update()

if name == 'main': # Forum message formatter messes this up
try:
setup()
while True:
loop()
except (Exception, KeyboardInterrupt) as e:
try:
from utility import print_error_msg
print_error_msg(e)
except ImportError:
print("please update to latest firmware")

Can anyone demonstrate the example for subscribing to certain MQTT topic? All I'm getting is an error: "'NoneType' object has no attribute 'subscribe'". Meanwhile publishing to MQTT works as it should.

Nice thing is that MQTT is now available in UiFlow 2 Alpha 11, however I can not manage to get it working. When trying to subscribe to a topic, I receive an error "AtributeError: 'NoneType' object has no attribute 'subscribe'".

Then probably the fact that Atom S3 currently supports only tiny subset of UIFlow features should be made clearer in the product description. I bought an Atom Matrix for a DIY watering project, was fairly impressed with the device (and the whole M5Stack concept) and decided that small local display for current humidity etc would be even better. So I bought the new AtomS3 (described as supporting UIFlow development platform) and currently can't connect it neither to my Watering sensors nor the MQTT data collection server. I will switch my development back to the Matrix and will be looking forward to switch it again when the features I need will be supported in UIFlow 2