3.5 Jack Input to Arduino

Hi Guys,

I have managed to put together a voice modulator with an Arduino Uno and Arduino Wav Shield. I saw this done via a online tutorial for cosplay. I have an Adafruit 1063 Electret Microphone Amplifier with Adjustable Gain connected and it work perfectly. The trouble I' m having is now I would like to connect a Throat Microphone which I have bought to it. The Throat Microphone works off a standard 3.5 Jack as input but I can't figure out how to wire this into what I already have as the modulator. I foolishly thought it would simply be a case of removing the adafruit microphone and wiring the VCC, Gnd and Out to the correct three parts of the jack but no sound comes through the devise now.

Anyone able to point me in the correct direction, tell me how to do it to how to make this work or what adaptive board I might need if there is one. Thank you very much in advance.

Microphones need a preamplifier (usually with a gain of around 100). Your Adafruit microphone board has one. How about the throat mic?

In addition, if it's an electret mic (or any kind of condenser mic) it has to be powered.

Finally, since the Arduino can't read the negative-half of an AC signal (it can actually be damaged by negative voltages) the output must be biased. (The Adafruit board's output is biased.)

FYI - Laptops and soundcards have a built-in preamp and they supply 5V to power an electret mic.

Thanks very much for your reply, the Thrat Microphone I have bought is this one http://www.ixradio.com/shop/throat-microphone-with-smartphone-adapter-xvtm821s-spa-single-transponder-xvtm821s-spa.html

I don't think it has a preamplifier, as you said it does work when plugged in to my laptop so I guess I need to put a preamplifier between the Arduino and the 3.5 jack. Is that correct? if so where would you advise I get one that is compact?

If not I apologies for my lack of knowledge.

Thanks again

The other question I had is as the Adafruit preamplifier with the microphone only has two connectors to the microphone how would you be able to connect the three inputs from the 3.5 jack to the preamplifier, as there are three connectors the Tip, Ring and Shield.

if so where would you advise I get one that is compact?

Maybe you can un-solder the mic from the Adafruit board and use it?

how would you be able to connect the three inputs from the 3.5 jack to the preamplifier, as there are three connectors the Tip, Ring and Shield.

You only need two connections (for a mono computer mic). You can leave the ring unconnected, or connect the ring & sleeve together. (Most of the schematics I found show the ring & sleeve connected together.)

Great thanks - I will give that a try - I already took the Mic off the adafruit mic and tried to connect two to it but haven't tried the second part of what you said - will give that a go tonight and see how I get on - thanks again

Unfortunately that didn't work - I wired the adafruit mic to the arduino and sound went through fine - then I took off the microphone part and connected one wire of that to the ring/sleeve and the other wire to the tip. I connected the ring and sleeve together and then tried without them being connected. There isn't even any static going through the speakers - as if nothing is connected at all.

Anyone have any ideas as to what I need to do now?

Thanks in advance

Electret mics need a voltage across the two connections to work.

Your throat microphone is very likely a dynamic microphone. The voltage across the 2 connections will prevent the dynamic microphone from giving an output.

Try and measure the resistance between all of the 3.5 jack connections. If you find a resistance, then these two connections are the ends of the coil of the dynamic microphone.

If you do not find a resistance or a very high resistance in the range of Mega-Ohms, then it is an electret mic. It could be that the adafruit board then doesn't provide enough voltage for the mic.

Also the output of a dynamic microphone is generally lower than from an electret microphone.

  1. If your throat mic is a dynamic mic, you can try and cut the right track on the PCB in order to remove the mic voltage.

  2. Or get a microphone amplifier which is suitable for dynamic mics.

I'm having exactly the same problem I just posted a thread before discovering yours. Did you ever find a suitable throat microphone to replace the electret one that came with your voice modulator or a workaround with a compatible amplifier?

Don't hold your breath! The OP hasn't been seen here for over three years! :cold_sweat: