sound detection

[antoni1]

hi
has anyone built a robot which can detect sounds using PIC??
Is it supposed that the output from the sound detection circuit should be 5V? for the PIC (i.e 16F877) to recognise it as an input?
(I m not using A/D i just trying to make the robot to move when hears a sound and stop when not.)

 

[DJ_ReL@X!]

You need a transducer, a little speaker will be ok. Then amplify the signal to get a maximum of 5 volts with an opamp. A gain of 200 would work. Use one of the two analog comparators in 16F877A. You set the reference and it gives you a bit when the sound is present.

 

[DirtyLude]

Anyone suggest a sutable opamp for this? I have a 3.3v ADC I'd like to feed, and I have no experience with opamps.