Don't know what to use

  • Hello,

    Thank you for your feedback.

    As I'm quite new on this kind of stuff (using pins to interact with an external component); I need some tips :)

    When I do this on UIFlow:


    I understand it activates the pin n°2 (LOW), when the "switch0" is activated. Am I right ?

    How can I identify the pin n°2 on my M5 Core basic with a base core bottom ?

    I think I need some documentation/tutorial to understand the correspondance between the pins used into UIFlow and the the pinmap on M5 Core Basic. Can I find this somewhere ?

    Thank you for your help

    Best regards

  • Hi,

    I finally got the relay working with M5 Core Basic !
    I think my mistake was to power the relay with 5v rather than 3.3v

    Here is my wiring:


    And here is the example UIFlow that works for me:


    Now I need to find a way to power the M5 Core Basic by using a DC 12V --> USB 5V connector and connect it to the DC 12V power supply I already use.

    Next step will be the hardest: understanding how PaHub works to interconnect the M5 Core Basic with:

    • RFID reader
    • M5 Scales kit
    • M5 Ultrasonic Distance Unit

    I will report progress here

    Thank you again for your help

    Best regards

  • Hi all,

    Another report here.

    Almost everything is ready.
    I'm quite sure the RFID2 reader won't do the job because of its short reading range; let's try and improve if required.
    I will certainly have to give this reader a try. (already ordered)

    1 question I had while testing: TOF and RFID2 seems to need Ports A or E. But Port E never worked (the unit is seen as "not connected" by the Core); forcing me to use a PaHub which is a pity because I have plenty of available ports with the ExtPort extension.
    Someone able to help me understanding why ? (If I could use port E; I could completely remove the PaHub)

    Here is the current setup:


    Last thing to do to complete the prototype: get a 12v --> 5V USB connector in order to power the M5 Core + 12v DC motor with a single source.

    Here is a simple UIFlow to check every component works correctly:

    Best regards

  • Hello all,

    Last part done (single power supply for M5 core + DC motor)
    I was also able to remove the PaHub by using the ExtPort (Port D). I had to change the dip switch value to:

    • Port D-1[2] = ON (to use GPIO22)
    • Port D-2[2] = ON (to use GPIO21)

    I then had to change the TOF module's port config in UIFlow to use the Port D:

    Final diagram:

    NB: DC(12v) to USB(5v) converter link

    Now let's get physcal parts printed and test it !

    Best regards

  • Cool and thanks for sharing your progress.
    When you get everything up and running, please create a build log on

  • Hi guys,

    New problem here: I'm unable to use this RFID reader from Seeed studio

    The reader is able to communicate by serial (9600 baudrate, 8 data bits, 1 stop bit, and no verify bit)

    I connected it with my Ext port Blue port PortC (stacked with my M5 Core Basic)

    • Reader Yellow wire (TX) --> Ext port (Port C) / PIN13
    • Reader White wire (RX) --> Ext port (Port C) / PIN14

    On UI Flow I tried this:


    When I put an RFID tag on the reader; a red led seems to indicate it detects the tag; but I get nothing printed on my M5 Core Basic screen.

    What did I wong ?

    Thank you for your help

    Best regards

  • Hello,
    Anybody here to help me on this blocking point?
    Thank you
    Best regards

  • @ajb2k3 hello,
    I would be really happy to share my project; but for this I will need some help on my last question on this topic 😉
    Any suggestion to unblock me ?
    Best regards

  • Have you got a micropython library installed for the reader?
    It looks like you set up the connection but you have yet to initialise the reader and tell it to start talking.

  • Hello,

    Thank you for your feedback.

    The code generated by the UIflow example from my last screenshot is the following:

    from m5stack import *
    from m5ui import *
    from uiflow import *


    uart1 = machine.UART(1, tx=14, rx=13)
    uart1.init(9600, bits=8, parity=None, stop=1)
    while True:
    if uart1.any():
    lcd.print((, 0, 0, 0xff0000)

    Do I need to add something else to this code to receive any signal from the reader ?

    Do tyou mean UIFlow requires additional libraries to be able to communicate over serial (UART) ?

    Thank you for your help
    Best regards

  • Hello @ajb2k3

    I took a look on your UIFlow handbook for some examples on serial communication.

    I found this:

    It seems the code is almost the same than the one generated for me by UIFlow.

    The imported libraries are the same than the ones I have in my code:
    from m5stack import
    from m5ui import
    from uiflow import

    On the example provided by my reader's provider; they import this library: " #include <SoftwareSerial.h>"

    But I think this is the implémentation for Arduino and I guess the equivalent UIFlow libraries are loaded through this:
    from m5stack import
    from m5ui import
    from uiflow import

    Do I miss something ?

    On my side I think the reader works because when I bring a RFID tag close to it; the status led of the reader lights up.
    But I still receive nothing on the M5 core RX PIN

    Thank you for your help
    Best regards