Trouble with using LMV358 to bridge headset and teensy

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rbwilcoxon11
Posts: 1
Joined: Wed Sep 26, 2018 11:24 am

Trouble with using LMV358 to bridge headset and teensy

Post by rbwilcoxon11 » 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: 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?

Markmilleru2
Posts: 2
Joined: Mon Oct 15, 2018 6:52 am

Re: Trouble with using LMV358 to bridge headset and teensy

Post by Markmilleru2 » Mon Oct 15, 2018 6:53 am

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


UhClem
Posts: 418
Joined: Sun Aug 03, 2008 6:11 pm

Re: Trouble with using LMV358 to bridge headset and teensy

Post by UhClem » Wed Oct 17, 2018 7:45 am

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.

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