Help Needed: RFID Reader Timeout When Adding Wi-Fi and MQTT Code on M5Stack with MicroPython

edraak

Hi everyone,

I'm working on a project using the M5 Dial with MicroPython and UIFlow 2.0, and I'm encountering an issue where adding Wi-Fi and MQTT code causes my RFID reader to timeout and throw exceptions. When I run the RFID code alone, it works perfectly, but when I include the Wi-Fi connection and MQTT functionalities, the RFID reader starts experiencing problems.

Problem Description:

RFID Reader Works Alone: The RFID reader functions correctly when running only the RFID-related code.
Issue When Adding Wi-Fi and MQTT: Including Wi-Fi connection code and MQTT client causes the RFID reader to throw timeout errors and sometimes leads to the device restarting.

Error Messages:

Exception during RFID operation: [Errno 116] ETIMEDOUT
Traceback (most recent call last):
  File "<stdin>", line XX, in main_loop
  File "unit/rfid.py", line X, in is_new_card_present
  File "driver/mfrc522/__init__.py", line XXX, in picc_request_a
  ... (additional traceback lines)
OSError: [Errno 116] ETIMEDOUT

What I'm Doing:

RFID Reader: Reading RFID tags using the built-in RFID unit connected via the M5Stack PORT.B (I2C).
Wi-Fi Connection: Connecting to a Wi-Fi network using the built-in Wi-Fi module.
MQTT Client: Publishing and subscribing to topics using the umqtt.simple library.
Asynchronous Tasks: Using uasyncio to handle asynchronous operations, including reading RFID tags and maintaining MQTT connections.

Code Snippets:

Here are the relevant parts of my code:

RFID Reading Loop:

async def main_loop():
    global rfid
    while True:
        try:
            if rfid:
                # Attempt to detect a card
                card_present = rfid.is_new_card_present()
                if card_present:
                    # Read card UID
                    card_uid = rfid.read_card_uid()
                    # Process the card UID
            else:
                print("RFID object is None, attempting to reinitialize")
                try:
                    rfid = RFID()
                    print("RFID reinitialized")
                except Exception as e:
                    print(f"Error reinitializing RFID: {e}")
        except Exception as e:
            print(f"Exception in main_loop: {e}")
        await asyncio.sleep(0.1)

Wi-Fi Connection Function:

async def connect_wifi():
    global wlan
    wlan = network.WLAN(network.STA_IF)
    wlan.active(True)
    await asyncio.sleep(1)
    wlan.connect('Your_SSID', 'Your_Password')
    while not wlan.isconnected():
        print('Waiting for Wi-Fi connection...')
        await asyncio.sleep(1)
    print('Wi-Fi Connected')

MQTT Connection Function:

async def connect_mqtt():
    global mqtt_client
    mqtt_client = MQTTClient('client_id', MQTT_BROKER, port=MQTT_PORT, user=MQTT_USER, password=MQTT_PASSWORD)
    mqtt_client.connect()
    print('MQTT Connected')

Initialization Function:

async def setup():
    global rfid
    M5.begin()
    # Initialize RFID
    try:
        rfid = RFID()
        print("RFID initialized")
    except Exception as e:
        print(f"Error initializing RFID: {e}")
        rfid = None
    # Connect to Wi-Fi
    await connect_wifi()
    # Connect to MQTT
    await connect_mqtt()

Observations:

Possible Resource Conflict: I suspect there might be a resource conflict between the RFID reader and the Wi-Fi module when both are active.
Task Scheduling Issues: The asynchronous tasks for Wi-Fi, MQTT, and RFID might be interfering with each other, causing timeouts in RFID operations.
RFID Timeout Only When Wi-Fi and MQTT Are Active: If I remove the Wi-Fi and MQTT code, the RFID reader works without any issues.

What I've Tried:

Using Asyncio Locks: Implemented asyncio.Lock() around hardware access code to prevent resource conflicts.

# Initialize a lock
lock = asyncio.Lock()

# In RFID operation
async with lock:
    # RFID read code

# In Wi-Fi and MQTT operations
async with lock:
    # Wi-Fi and MQTT code

Adjusting Task Frequencies: Increased sleep durations in non-critical tasks to reduce CPU load and potential interference.
Ensuring Proper Initialization: Made sure all variables and hardware components are properly initialized and declared as global where necessary.
Simplifying the Code: Tested the code by removing the Wi-Fi signal strength monitoring task, but the issue still persists when MQTT is active.

Questions:

Resource Contention: Could the RFID reader and Wi-Fi module be conflicting due to shared hardware resources? If so, how can I effectively manage this conflict?
Task Synchronization: Is there a recommended way to synchronize tasks involving RFID, Wi-Fi, and MQTT to prevent interference?
Hardware Limitations: Are there known limitations with the M5Stack Core2 when using RFID and Wi-Fi/MQTT simultaneously?
Alternative Approaches: Suggest some other methods to handle such scnarios

Additional Information:

Device: M5Stack Core2
Programming Language: MicroPython
RFID Reader Connection: Built-in RFID unit connected via I2C (PORT.B)
Wi-Fi Module: Built-in Wi-Fi module
MQTT Library: Using umqtt.simple
Asyncio Version: Using uasyncio for asynchronous operations

Any insights or suggestions would be greatly appreciated! I'm looking for guidance on how to resolve this issue so that I can use RFID, Wi-Fi, and MQTT together without conflicts.

Thank you!

felmue

Hello @edraak

I am confused about whether you are using an M5Core2 or an M5Dial. Could you please clarify?

Also it would help if you could share your complete program in the UIFlow2 Project Zone.

Thanks
Felix

edraak

@felmue
Hi, Apologies for confusion I am using m5 dial
and below is the link of my code

https://uiflow2.m5stack.com/?pkey=7b06b0d459f14c8ab16e70d5b073bf76

felmue

Hi @edraak

I am running your code with test.mosquitto.org as MQTT broker; but so far I was not able to break it, e.g. no ETIMEDOUT error so far.

Thanks
Felix

felmue

Hello @edraak

one thing I would change. After card_uid = rfid.read_card_uid() check for read being successful: e.g. if card_uid != None:

Thanks
Felix

edraak

@felmue

This error occurs inconsistently—sometimes very frequently, and other times, it only happens after 4,000 or 5,000 scans. In some cases, I encounter the issue after just 20 scans.