I want to find a simple, easy, small, solid circuiti to detect environment sound pressure level
can anyone post a good schematic?
no luck with my schema
it works fine, but is very prone to motor noise
i have tryed to decouple all inserting caps and inductors but it seemms that motor produce frequancy near to audible band so it's tricky !
sparkfun is interesting piece of hardware... wandering if it's immune to noise
going to test
reporting back soon
done some test
puting cap on feedback resistor is effective !
but... damn, i need at leat a 1nF cap to suppress motor noise decently
with this capacitance there is a drawback: mic frequencies are suppressed too :(
I can only suggest that you put a 2.2uF bi-polar (non polarised) electrolytic capacitor across your motor as well as a 0.1uF monolythic. Monolythic ceramic capacitors have a low ESR which makes them ideal for noise0 suppression.
Try using shielded cable for the mic as well as the motors.