Cellphone boom handsfree for laptop headset

[d4d4ng]

Hi All,
Just wants to experiment. I had a spare cellphone boom handsfree laying around. Tried to connect the earphone part to earphone socket of laptop with wires, it worked. But did't work for microphone part . I just heard noise if I used sndrec32.exe to try it.
May be it was just an impedance mismatched between handsfree mike with laptop mike socket. Appreciate if some nice person in this forum shows me how to make it work. Do I need a circuit to bridge the mike and the socket. What kind of circuit it is if it needs.
Thanks in advance.

Amri

 

[Agent 009]

I dunno much abt such things, but could u try the mic on another stuff, like a stereo for example? You could then check if the mic itself isn't working. If it's, maybe you should measure current flow, then use a normal mic on ur laptop and check if there's any difference...

 

[audioguru]

Maybe the microphone is wired with 3 wires but the laptop's mic jack uses only two wires or the other way around.

 

[zachtheterrible]

Tried to connect the earphone part to earphone socket of laptop with wires, it worked.

How do you expect to get sound out of the earphone socket??? :lol:

May be it was just an impedance mismatched between handsfree mike with laptop mike socket

Now you're saying it was the mike socket . . . im confused! How did the earphones work when it was plugged into the mike socket?

I think that you might have it plugged into the earphone socket of the computer. The computer won't be able to "hear" the headphone socket.[/quote]

 

[d4d4ng]

Sorry for not so detail to described.
FYI, the laptop has one socket for earphone/external speaker and one other for microphone
The boom cellphone handsfree consisted of an earphone and a mike at the end of the boom and has 4 connectors at the jack ( 2 for earphone and 2 others for mike). I tried to connect the earphone/external speaker socket of laptop to earphone connectors of the handsfree and I can hear the music from Media Player. But I could not hear my voice using sndrec32.exe when I spoke thru the mike that I connected to microphone socket of laptop.

Attached. please find the picture of handsfree.

TIA

 

[Roboticinfo]

reply

Usually the cell phone input has a smaller jack

it will not work you will have to buy a cpu mike or make one.

 

[d4d4ng]

Thanks GTAman.
You are right, the jack of cellphone is small (2.5mm) but I connected the jack to 2 larger jacks (3.5mm) for earphone and mike connectors.
Hope you can catch what I meant.

 

[Roboticinfo]

reply

Ya I did but still have dought's, best to buy new or make your own.

 

[audioguru]

The mic is probably an electret type that needs power.
Maybe you had its two wires reversed so that it had the wrong polarity.
Maybe the laptop circuit is designed for a coil and magnet dynamic type of mic and therefore doesn't provide power for an electret type.
Maybe the mic is wired with 3 wires and one wire is shared with the earphone for power or for ground.

 

[d4d4ng]

Agent 009, audioguru,zachtheterrible and GTAman,
Thanks for all of your information
May be at the end, I should get a separate headphones and a microphone :wink:
Just to satify my curiosity, how can I tell it's an electret or dynamic type of microphone ?

Thank in advance.

Amri

 

[Roboticinfo]

reply

They both have a similer look, it is best just to get the technical spec's.

 

[Agent 009]

By the way,

How did the earphones work when it was plugged into the mike socket

I know that mic's and speakers r "symmetric", u still can use one in place of the other, to some certain xtent (impedance, powerrating...). But I think for small headset like this one, the earphone could work very close to a microphone, and vice versa...

 

[Roboticinfo]

reply

All it is, is the connection and they were specificly made for phone's only and nothing else.

 

[indecided]

Sounds like a wiring problem.

Looks like a Nokia handsfree you have..

Which should be (from tip to ring) Ear,Mic, Ground ear, Ground mic.

As I have tried in the past, the microphone is an electric condenser mic, gardern variety minature. However, I think your notebook simply does not provide plug-in-power, as it is referred to.

Try plugging it into a PC and see how it goes.. Sound Blaster cards do provide plug-in power in the middle ring.

https://www.epanorama.net/circuits/microphone_powering.html

might be a useful reference.

 

[Roboticinfo]

reply

It is not because of that

the input is way smaller then the laptop or pc input.

it was maid just for cellphone's, you could modify it but it would look funny.

 

[indecided]

Re: reply

He already said he rewired the jack..

It is not because of that

the input is way smaller then the laptop or pc input.

it was maid just for cellphone's, you could modify it but it would look funny.

Thanks GTAman.
You are right, the jack of cellphone is small (2.5mm) but I connected the jack to 2 larger jacks (3.5mm) for earphone and mike connectors.
Hope you can catch what I meant.

 

[d4d4ng]

Thanks for your input.

indecided is right, it's a Nokia handsfree.
I have rewired the 2.5mm jack with 2 of 3.5mm jacks and also the order of the rings is like indecided wrote.
I will try to provide the power to the electret mike just like the link by indecided. Rig them on a breadboard and using a 9v battery.

Will back with report, success or failure

 

[d4d4ng]

Hi All, back with you again :?
I googled and came up with this link https://www.epanorama.net/circuits/micamp.html.
I did the breadboarding with a 9v battery as power source and tried to connect the circuit to my laptop. When I recorded my voice using sndrec32.exe, I could hear my voice but with background of high pitch noise due to interference.
How can I avoid or minimize the interference? Should I use a screened cable or put the whole circuit in a metal box ?

Please for your advice. Thanks.

Amri

 

[audioguru]

Your headset microphone probably has a screened cable to avoid interference. You added a resistor to power it. Didn't you use screened cable to feed it to your laptop? Unscreened cable makes a nice antenna for the very sensitive mic input on the laptop. :lol:

 

[d4d4ng]

Thanks audioguru for your quick reply.
Right, the electret mike got power via a resistor, just like the article in the link I provided. I intended to put the circuit on a PCB, so the output of coupling cap soldered to 3.5mm jack that will be put into laptop mike input socket ( should be no extension wire actually )
The previous story I told you is what I experienced using a breadboard, so I had to use extension unscreened cable
Do you think I need an audio bandpass filter to get rid of interference. If you do, can you provide the link to the audio bandpass filter schematic or article ?
Thanks in advanced.

Amri.