I'd like to feed a module with audio output from a phone's jack instead of the mic the board cames with.
As I said the board is designed to operate with an electret mic with the following specs:
- Sensitivity -38dB
- Load Impedance 2.2K
- Operating Voltage 3V
The mic produces a signal that is 20mV peak-to-peak, centered around 1.5V, but anything in the [0.5V,2.5V] range should do according to the manufacturer.
I want to take out the mic and instead connect a phone's audio jack to the module.
I have two questions:
- Are audio jack signals standard? What would be a normal signal coming out from an standard smartphone?
- Assuming an average phone, what would be the minimum required circuit able to convert (most likely attenuate?) the audio jack output to the above mentioned levels?