Hi all,
I have built an alarm system that plays different siren patterns triggered by a PIR sensor input using the Tone library. It works as expected with the PWM output amplified through an LM386 amp module, however i would like to significantly increase the volume and am wondering if i can easily connect the PWM output to the amp input in the link below or will i require some protection circuitry for the Arduino pin. Any advise or guidance is very much appreciated.
Schematics or documentation? I sorta doubt you'd have to protect the Arduino pin from the amp. More the other way around. The amp board probably expects a line-level input of around +/-1V. I don't know what you've got hanging off the Arduino pin right now, but if you're not reducing the voltage significantly, you're likely to over-drive the amp.
Overdriving will just make a more distorted output usually.
Run the PWM thru a pot to reduce the level, then thru a 10uF cap to get the output to be +/-1V or so into the amp.
Should end up sounding like this:
This a 13-channel organ I made using blink-without-delay style programming. Tuning matches my wife's piano very nicely. The channels go thru 10uF cap and 1K resistor, combined at a single pot which then feeds the speaker/amp.
Full details in this topic
http://forum.arduino.cc/index.php?topic=179761.0
Thank's guys for your advise, just to clarify CrossRoads suggestion PWM pin to one end of the pot and wiper of the pot to amp through the cap, other end of pot to GND is that correct.
Yes. PWM to the cap to leg of pot, wiper amp, other leg of pot to Gnd will also work. Need the cap in series to remove DC component of the signal so the signal will look like AC swinging above/below Gnd.
Cheers CrossRoads thank you for your help. BTW very nice organ project.