How could I evaluate the signals from the audio input so that it acts as a switch to turn on my Bluetooth Speaker?

  • \$\begingroup\$ What kind of signals? \$\endgroup\$
    – Eugene Sh.
    Feb 14, 2017 at 20:56
  • \$\begingroup\$ Audio Signals which is coming into the Audio In of Bluetooth Speaker \$\endgroup\$
    – karadayi
    Feb 14, 2017 at 21:23
  • \$\begingroup\$ If it's a normal stereo socket, these usually have additional pin which gets shorted or opened when the jack is inserted. That might be the easiest choice. \$\endgroup\$
    – anrieff
    Feb 14, 2017 at 23:07

1 Answer 1


LM311 comparator. Or any modern similar chip. LM311 has open collector and emitter on its output transistor so is easy to use with any power supply. http://www.ti.com/product/LM311


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