Go Back   Home > Forums > General Interest > Everything Else

Everything Else Anything related to audio / video / electronics etc) BUT remember- we have many new forums where your thread may now fit! .... Parts, Equipment & Tools, Construction Tips, Software Tools......

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 21st June 2011, 01:16 PM   #1
Ramrod is offline Ramrod  United States
diyAudio Member
 
Join Date: May 2011
Default 2-way radio headset microphone....?

Im trying to make my own headset for a motorcycle helmet so that it will work with a motorola 2-way radio among other things.

Im a little confused about the microphone wiring. The motorola radio has a 2.5mm stereo jack with the speaker signal on the tip, microphone input on the ring, and ground on the sleeve. I bought a cheap hands free set for the radio that had a mono earbud and a mic with push to talk button, made by motorola. I took it apart and there is a board with a capacitor and resistor in a circuit with what appears to be an electret mic capsule.

How does this work with only a ground and one other connection to the radio? is it actually a dynamic mic if so what is the cap and resistor for? How can i tell?

The mic signal ring on the radio connector is outputting like 3.5VDC. I did hook up a dynamic mic element to the mic ring from the radio in series with a NO pushbotton to ground as a PTT, and when the PB was depressed it worked fine. I would like to use an electret mic since noise cancelling ones are cheap and readily available.

THANKS
  Reply With Quote
Old 21st June 2011, 03:36 PM   #2
Ramrod is offline Ramrod  United States
diyAudio Member
 
Join Date: May 2011
So this circuit must have the audio signal from the mic and the power supply for the electret combined into one line (phantom power?) not too familiar with mic circuits. The RC circuit on the board must be a filter....?
  Reply With Quote
Old 21st June 2011, 04:17 PM   #3
diyAudio Member
 
Frank Berry's Avatar
 
Join Date: Sep 2003
Location: Midland, Michigan
The cap and resistor are designed to keep the 3.5 volts away from the dynamic mic element. The resistor is probably there to bleed off the 3.5 volts across the capacitor when the mic is disconnected from the radio.
__________________
Frank
  Reply With Quote
Old 21st June 2011, 07:32 PM   #4
Ramrod is offline Ramrod  United States
diyAudio Member
 
Join Date: May 2011
If it were a dynamic mic why the radio output 3.5VDC on the signal input? Or do you actually think it is an electret element?

Sorry if im an idiot.
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
FRS radio headset/microphone questions Ramrod Everything Else 0 15th June 2011 04:09 PM
Blue tooth headset used for wireless nige838 Analog Line Level 0 10th February 2011 03:28 AM
Magnetic contact microphone from Radio Shack audio transformer Dogue Instruments and Amps 0 11th April 2009 10:39 PM
multi media headset gizmo1160 Everything Else 0 4th October 2007 03:32 PM
Nokia N-gage HDD-2 Headset >jacko< Everything Else 0 21st April 2005 10:23 AM


New To Site? Need Help?

All times are GMT. The time now is 04:38 AM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright 1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2