I'm working with a MP3 player module: https://wiki.dfrobot.com/DFPlayer_Mini_SKU_DFR0299

The pin named "IO2" will do the following: at short button press it will start to play the mp3 file inside the sd card. a long button press will increase the volume.

What I would like to do is to eliminate the ability for long press - meaning even a long press will be counted as a short press so the user will not have the option to change the volume of the audio file. I know I can do it with an arduino but I would like to know if there is any analog circuit (transistors resistors?) for doing it ?


  • \$\begingroup\$ 555 timer configured as a monostable with a RC differentiator on the trigger input. In its basic form this will give a 'high' going pulse out. \$\endgroup\$
    – user173271
    Nov 13, 2022 at 6:37
  • \$\begingroup\$ Or it could be done with a couple of inverting schmitt trigger not gates with a RC differentiator and a diode to discharge the capacitor quickly. \$\endgroup\$
    – user173271
    Nov 13, 2022 at 6:45
  • \$\begingroup\$ It may be better to remove the distinction between long button press and short button press and make everything a short button press to avoid confusion. \$\endgroup\$
    – Amit M
    Nov 13, 2022 at 8:15

2 Answers 2


Use a 555 timer to trigger off the rising edge or to flip flops with a delay in between them that trigger off the rising edge of the button press

  • 1
    \$\begingroup\$ is there a schematic for that type of circuit? \$\endgroup\$
    – Omer
    Nov 13, 2022 at 8:07

A push button switch, with 1 NO + 1 NC contacts, and a capacitor would do to generate the pulse.

The internal pull-up resistor is to be enabled.

enter image description here

  • \$\begingroup\$ the problem is button must be connected to GND \$\endgroup\$
    – zhekaus
    Sep 27, 2023 at 23:30
  • \$\begingroup\$ @zhekaus - Hi, Thanks for the feedback. My answer has been edited. \$\endgroup\$
    – vu2nan
    Sep 28, 2023 at 4:05

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