Hello,
I've a newbie question. Is there an already made tutorial or info's about how to connect a 3.5mm jack to Arduino?
I've found mostly how to detect audio from a microphone.
What I'd like to do is to use earphones and connect them to Arduino with a 3.5mm jack and reproduce a sound like a buzzer (or just a bip) when something happen.
I've thought about connecting a MOSFET to power of Arduino (5v or 3.3v) and earphone to not damage pins. Will this work like a buzzer?
On a "regular Arduino" (The Uno, etc., with the ATmega chip) the "absolute maximum" allowable current form an output pin is 40mA.
From Ohm's Law that works out to a minimum resistance of 125 Ohms. Headphone & earphone impedance varies, but 32-64 Ohms is typical. (A 4 or 8-Ohm speaker is even worse!)
A MOSFET or transistor will work with a "digital" output but you can just put a resistor of 125 Ohms in series with the headphone and it will be safe. The resistor will knock-down the loudness but it will probably still be too loud if you stick the thing in your ear! So you may need a higher-value resistor.
If you have an Arduino with a DAC (true analog output) you'll need a linear audio amplifier which is usually a chip or more than one transistor/MOSFET.
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