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Trouble with using LMV358 to bridge headset and teensy

Posted: Wed Sep 26, 2018 11:41 am
by rbwilcoxon11
I have a project where I am trying to get audio from an Android headset accessory into a teensy audio board line in using the LMV358 op Amp breakout board.

I am not able to get any signal from the LMV358, only a floating voltage at around 2.5v.

I am using this information for the arduino spec to wire it: https://source.android.com/devices/acce ... adset-spec

Essentially, I am wiring the mic out to the input of the LMV358, and plugging the output of the LMV358 straight to the line in of the teensy audio board.

My question is: do I need additional circuit components? Are my assumptions correct that this setup should work?

Re: Trouble with using LMV358 to bridge headset and teensy

Posted: Mon Oct 15, 2018 6:53 am
by Markmilleru2
rbwilcoxon11 wrote: Wed Sep 26, 2018 11:41 am I have a project where I am trying to get audio from an Android headset accessory into a teensy audio board line in using the LMV358 op Amp breakout board.

I am not able to get any signal from the LMV358, only a floating voltage at around 2.5v.

I am using this information for the arduino spec to wire it:best cordless drill best miter saw best gaming laptop under 500 best reel mowerEssentially, I am wiring the mic out to the input of the LMV358, and plugging the output of the LMV358 straight to the line in of the teensy audio board.

My question is: do I need additional circuit components? Are my assumptions correct that this setup should work?
I am also facing same problem

Re: Trouble with using LMV358 to bridge headset and teensy

Posted: Wed Oct 17, 2018 1:00 am
by Markmilleru2

Re: Trouble with using LMV358 to bridge headset and teensy

Posted: Wed Oct 17, 2018 7:45 am
by UhClem
It is difficult to tell from what I have found but it is possible that the mic requires a DC bias voltage to operate. The documents mention a resistor (2.2K) in series with a small voltage (2.2V) but it isn't clear if that is needed by the mic or just to detect switch closures.