Hi all, just a quick one, I have to produce some frequencies on my Uno to help develop another app on a Mega.
I'm looking around for a simple circuit to connect the Arduino to a headphone jack, but for now PWM will be suitable.
My initial problem is I'm sampling a little mic setup ( freetronics module ) but it has incredible noise on the line, so for testing purposes I want a clean signal.
Is it fine to simply connect the grounds together and wire the Uno PWM pin directly into the analog in pin?
Or is a resistor needed to prevent a short circuit?
Also anybody tried and had good results with any headphone jack circuits, everything I have looked at seems to be a variation of some sort of peak detector, whereas I want raw audio biased for Arduino voltages.