• Recent
  • Tags
  • Unsolved
  • Solved
  • MagicMirror² Repository
  • Documentation
  • 3rd-Party-Modules
  • Donate
  • Discord
  • Register
  • Login
MagicMirror Forum
  • Recent
  • Tags
  • Unsolved
  • Solved
  • MagicMirror² Repository
  • Documentation
  • 3rd-Party-Modules
  • Donate
  • Discord
  • Register
  • Login
A New Chapter for MagicMirror: The Community Takes the Lead
Read the statement by Michael Teeuw here.

Button

Scheduled Pinned Locked Moved Troubleshooting
23 Posts 9 Posters 21.1k Views 5 Watching
Loading More Posts
  • Oldest to Newest
  • Newest to Oldest
  • Most Votes
Reply
  • Reply as topic
Log in to reply
This topic has been deleted. Only users with topic management privileges can see it.
  • D Offline
    dicker182
    last edited by dicker182 Jul 24, 2016, 6:23 PM Jul 24, 2016, 6:22 PM

    Hello,

    Im running MMM-Button Modul und GPIO PIN 9. Everything is working fine. But sometimes my Tagesschauvideo starts without my hand. I did nothing and “pm2 logs mm” sad to me: button pressed. Any idea why this happens?

    1 Reply Last reply Reply Quote 0
    • D Offline
      dicker182
      last edited by Jul 25, 2016, 3:33 PM

      Here a picture of my pm2 logs over the night:

      0_1469460451271_Bildschirmfoto 2016-07-25 um 17.27.13.png

      I never pressed the button :(

      C 1 Reply Last reply Jul 26, 2016, 9:26 AM Reply Quote 0
      • K Offline
        KirAsh4 Moderator
        last edited by Jul 26, 2016, 4:35 AM

        What’s listening for the button? How is it configured? How is the GPIO pin configured?

        Two possibilities:
        a) the button is faulty
        b) the button is left FLOATING

        A bit of lesson here:
        In order for a button to get registered, the controller needs to be able to detect a voltage differential. Whether that’s 0V to 3.3V, or -5V to 0V. This means that the button needs to be at a known level compared to what the controller is set to register a trigger. If the controller is meant to detect a HIGH, or 1, then the button must be referenced to ground, or 0V. If the controller is set to detect a LOW, or 0, then the button must be referenced to the pin’s high voltage, 3.3V or 5V. This is called pulling the button UP or DOWN. When the button is pushed, it will then register the voltage difference that the controller will recognize.

        A button that has no reference to either a LOW or HIGH is called a FLOATING button. This is bad! A floating button will randomly trigger and the controller will “see” random triggers from it.

        So, how is the button set up, how is the GPIO set up, what’s the code that’s attempting to read the button?

        A Life? Cool! Where can I download one of those from?

        1 Reply Last reply Reply Quote 0
        • C Offline
          CGabo @dicker182
          last edited by Jul 26, 2016, 9:26 AM

          @dicker182

          And to complement @KirAsh4 comment: probably the cause is some voltage / EMI feedback, likely due to the wires and switches.

          From what I see, the Pi does not have protective diodes on the inputs like the AVR chips (and Arduino) do. As a result, feedback to the Pi can probably cause the behaviour which you experienced. Try to switch on/off some lights and electrical devices and see the result.

          To correct this condition, use a combination of current limiting, filtering and shielding.

          You could use for current limiting, a 1K resistor in line with the switch, installed on a PCB inches from the Pi. Also use a low-pass filter made up of another pull-up / pull-down resistor and a capacitor alternatively to the build in PULL-UP and PULL-DOWN resistors of the PI.

          Here are some additional links:

          https://www.raspberrypi.org/forums/viewtopic.php?t=53548

          http://www.digikey.com/en/articles/techzone/2012/apr/protecting-inputs-in-digital-electronics

          1 Reply Last reply Reply Quote 0
          • D Offline
            dicker182
            last edited by Jul 26, 2016, 8:13 PM

            Both, thank you for your answer. I will try to give you more informations. The following button from Ebay are used:

            http://www.ebay.de/itm/272129888717?_trksid=p2060353.m2749.l2649&var=570940259633&ssPageName=STRK%3AMEBIDX%3AIT

            Art-Nr. 041

            At first, I tryed the configuration from PtrBld´s howto:

            0_1469563372766_upload-9e2a744a-191c-4bc0-a573-f60bb97298ea

            0_1469563330027_upload-82d3e24f-3dc3-445c-b383-2bfbd97945fd
            https://developer.microsoft.com/de-de/windows/iot/win10/samples/PushButton.htm


            After the false positiv pressed buttons, I tryed the actually config:

            0_1469563460478_upload-01973e92-35f2-4c6e-a8f0-54d28cd740ee https://dracarysdiy.files.wordpress.com/2016/03/button.jpg?w=474

            But the problem is always the same.

            @CGabo, I will have a look to your links tomorrow. But I am not an electrican, so I hope to understand.

            Thank you in advance!

            1 Reply Last reply Reply Quote 0
            • K Offline
              KirAsh4 Moderator
              last edited by Jul 26, 2016, 8:51 PM

              Yeah, that’s a floating button. You need a pull-down on it, a known state, so the rpi can detect a change. You can either do that in software with RPi.GPIO and configuring it as such:

              GPIO.setup(PIN, GPIO.IN, pull_up_down=GPIO.PUD_DOWN)
              

              Or through hardware:
              https://www.cl.cam.ac.uk/projects/raspberrypi/tutorials/robot/buttons_and_switches/

              A Life? Cool! Where can I download one of those from?

              1 Reply Last reply Reply Quote 0
              • D Offline
                dicker182
                last edited by dicker182 Jul 27, 2016, 12:09 PM Jul 27, 2016, 11:58 AM

                Okay, now I have a script button.py which starts with rc.local after boot.

                import RPi.GPIO as GPIO
                import time
                
                GPIO.setmode(GPIO.BCM)
                GPIO.setup(9, GPIO.IN, pull_up_down=GPIO.PUD_DOWN)
                GPIO.cleanup()           # clean up GPIO on normal exit
                

                But it´s also not working. Did I miss something?

                1 Reply Last reply Reply Quote 0
                • K Offline
                  KirAsh4 Moderator
                  last edited by Jul 27, 2016, 7:36 PM

                  Different permissions. Your rc.local runs with system privileges, however the MM² task runs as the pi user. You need to have those GPIO setting in the script that the pi user runs.

                  A Life? Cool! Where can I download one of those from?

                  1 Reply Last reply Reply Quote 0
                  • D Offline
                    dicker182
                    last edited by dicker182 Jul 27, 2016, 8:35 PM Jul 27, 2016, 8:25 PM

                    Okay thanks, the script now starting as user pi.
                    Other question, has my button.py script to run in a loop?

                    EDIT: Okay the message “button pressed” are coming when I turn the floor lights on 0o?

                    1 Reply Last reply Reply Quote 0
                    • K Offline
                      KirAsh4 Moderator
                      last edited by Jul 27, 2016, 8:47 PM

                      1. Take out that 'GPIO.cleanup()' call that you have. That resets everything you just did above it.
                      2. Button getting triggered because you turning on the floor (?) lights is because that button is still floating, see #1 above.
                      3. I’m assuming the rpi isn’t on the same circuit as the floor (??) lights, a voltage difference could also falsely trigger the button.

                      A Life? Cool! Where can I download one of those from?

                      1 Reply Last reply Reply Quote 0
                      • 1
                      • 2
                      • 3
                      • 1 / 3
                      1 / 3
                      • First post
                        8/23
                        Last post
                      Enjoying MagicMirror? Please consider a donation!
                      MagicMirror created by Michael Teeuw.
                      Forum managed by Sam, technical setup by Karsten.
                      This forum is using NodeBB as its core | Contributors
                      Contact | Privacy Policy