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I've a Bluetooth + Aux speaker which needs to be turned On manually after giving power. I wanted it to start functioning as soon as I switch the power On.

I opened it, there was a tactile push button which needed to be pressed for around 1.5 seconds to turn the speakers On. I solded both wires (on one side) of push button with each other. It worked and speakers start working after giving power.

Now the problem is; since the switch is treated as constantly pressed, inputs of other switches (volume, mode, lights) are ignored by the controller.

I'm not a professional, just an amateur hobbyist. How it will be possible to pass current between two pins of push button for only a few seconds when power is switched On?

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2 Answers 2

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You can try circuit below, it needs a Gnd also. It holds the output on for about 4sec after input signal come. Then falls to zero.

enter image description here

Edit:

If you don't know how the button is connected, you can use a relay circuit below. Connect Vcc and Gnd to power supply of your device, this circuit doesn't draw much so no worry. The only think is necessry is to choose a relay (its coil voltage) according voltage of power supply you connect to it. (5v or 12v).

enter image description here

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  • \$\begingroup\$ Input & output have two wires in your diagram in my layman understanding, don't we need to connect only one wire with another? Two legs of each side of a tactile push buttons are symmetric I think. I can't modify existing circuit but can add any resistance or capacitance between legs of the switch. Any guidance will be appreciated. \$\endgroup\$
    – Simptive
    Commented Sep 29, 2021 at 20:24
  • \$\begingroup\$ There are many options how your switch can be connected. I would start with multimeter, set it to measure resistance (lowest range) and find if one of these two pins have a ground connection (resistance < 1ohm to Gnd). Finding ground is easy, its ussually large place of copper on PCB or minus of filtrating electrolytic capacitors. \$\endgroup\$
    – user208862
    Commented Sep 29, 2021 at 20:53
  • \$\begingroup\$ Regarding your question about "just connecting two wires together" - yes, its possible with relay (relay doesnt care about exact connection), but that needs a power supply 5v/10mA at least to be able to switch. If you have a power supply available in your device there is no problem to do it. \$\endgroup\$
    – user208862
    Commented Sep 29, 2021 at 20:59
  • \$\begingroup\$ Yes, there will be 5v 2a power available at the time of switching. I can connect relay with it. I will check what relay options I have in market. Do I need to add resistor or capacitor to keep it connected a few seconds? \$\endgroup\$
    – Simptive
    Commented Sep 29, 2021 at 21:27
  • \$\begingroup\$ Please check aliexpress.com/item/1005001495955903.html is it something ready made I can use with minimum custom work? \$\endgroup\$
    – Simptive
    Commented Sep 30, 2021 at 6:34
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Yes, but to do it efficiently will require some reverse engineering. You need to figure out how the switch is wired, is it a high side switch? a low side switch? part of a switching matrix?

If it's a high side switch then a circuit like in Michal answer is appropriate, if it's a low side switch then a mirror image of that circuit with a NPN insead of a PNP would be appropriate, if it's a matrix things get rather harder.

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