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Can't get homemade headset to be recognized by Android

Hyerman

New Member
Hi,

This is my first post on this forum. My apologies if it is the wrong section or I get anything wrong.

I am trying, and failing, to create a simple headset for an android phone out of basic components. My design only has one speaker rather than the two that a headset normally has. It also doesn't have any of the fancy control buttons. It just has a single speaker and a microphone.

The android spec for audio pugs can be found here. https://source.android.com/devices/accessories/headset/plug-headset-spec#electrical
The jack side of the android spec can be found here.

The datasheet for the microphone I have been using can be found here.
The datasheet for the speaker I have been using can be found here. NOTE: this is a link to a pdf download rather than a web page.

The CTIA wiring for 3.5mm plugs is described rather well in this post.

I wired my headphone up the same way as the CTIA diagram in the prior link with a few exceptions:
1) I only used one speaker rather than two. I wired up the right speaker and not the left speaker.
2) I added a 110 ohm resistor in front of the speaker so that the combined resistance on that line would be 117 ohms. The android plug spec indicates that the resistance should be between 32 and 300 ohms.
3) I added a 520 ohm resistor upstream of the microphone so that the combined resistance on that line would be 1120 ohms. The android plug spec indicates that the resistance should be greater than 1000 ohms.

When I plug in my headset I get nothing. Nothing comes thru the microphone or out thru the speakers. My phone will continue to use its built in speakers and microphone. I also use an app that detects and indicates headphone insertion. An app that works pretty well to determine if a headset with-or-without a microphone is attached is called “Headset Notifier” on Google Play. I turn off all the options for it so that it only comes on when I want it to.

For comparison, I have a cheapo Skull Candy headset with a microphone. It works great in my android phone.

I checked the resistance of the various plug contacts on both my headset and the Skull Candy headset. I see what I expect on my headset. The Skull Candy headset has infinite resistance on the sleeve connections, which I don't understand.

Here is my naming conventions for the plug.
Tip-Spkr-L
Ring-Spkr-R
Ring-Ground
Sleeve-Mic


Contact 1Contact 2Skull CandyMy headset
Ring-Spkr-RTip-Spkr-L40 ohmsInf
Ring-GroundTip-Spkr-L20 ohmsInf
Ring-GroundRing-Spkr-R20 ohms117 ohms
Sleeve-MicTip-Spkr-LInfInf
Sleeve-MicRing-Spkr-RInf1120 ohms
Sleeve-MicRing-GroundInf1120 ohms


I appreciate any guidance that can be provided. I am a software person, but 30 years ago I had an aerospace engineering degree and took basic 200-level circuit courses. My understanding of your comments won't go much beyond that.

Thanks,

Hyer
 

rjenkinsgb

Well-Known Member
Most Helpful Member
The audio output to the speaker will be divided down by the ratio of the total resistance to speaker resistance; if it worked, you would be getting about 1/15th the volume you should.

Try a 22 Ohm resistor, one in series and one connected directly from left to ground, so the other channel has a DC load.
Or 10 series and 22 for the other channel.
The left output (tip) may be the one used for connection sensing.

If you don't have any other resistors, use a 110R from left to ground, so it sees a load, just to confirm that causes it to switch over.

You should not need any resistor in series with that mic.
 

Hyerman

New Member
rjenkinsgb ,
I am sorry to say, but your suggestions didn't work. I am still unable to get my homebuilt headset to work. The android phone won't recognize my headset. Any other suggestions?
 

rjenkinsgb

Well-Known Member
Most Helpful Member
Strange!

Try just two resistors, from the plug tip & first ring to the second (ground) ring?That should be seen as headphones connected?
 

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