Urgent Help Required

Hi Friends,
I am trying to get readings analog readings from the sound sensor. When I tried taking readings without playing any sound then I noticed that the reading was falling continuously. Can anyone tell me why is this happening? The readings are as follows:
793
790
793
790
795
787
791
778
789
784
781
778
784
780
775
776
774
779
771
775
766
774
767
768
765
768
762
766
762
754
759
762
755
756
753
754
754
753
754
750
748
748
750
747
740
744
741
742
739
744
743
739
734
746
730
731
731
733
733
732
727
727
727
732
725
729
725
729
725
727
722
723
718
718
720
716
719
711
715
709
720
711
713
713
709
712
711
711
704
707
707
703
709
699
706
704
697
705
696
699
698
698
699
695
703
694
696
695
692
695
689
692
694
691
692
686
692
689
686
690
681
681
688
681
684
683
685
679
680
681
676
680
676
679
683
674
678
671
676
664
674
679
668
674
671
675
668
669
668
667
671
673
667
663
664
675
662
668
666
665
661
661
664
655
662
658
662
659
658
656
655
659
655
660
653
664
655
652
654
652
655
652
653
651
652
653
649
652
647
651
644
647
651
649
648
646
647
643
648
643
645
645
642
644
640
645
638
642
640
642
639
637
642
638
639
635
635
635
637
634
634
636
636
635
632
633
632
634
631
634
628
632
642
631
627
631
636
632
645
629
628
627
626
626
626
627
624
621
621
623
622
623
625
624
621…
and so on . It continues so drop.
Why is this happening?
Thankyou

As subject

Hi Kavish

You might want to modify your post and cut down the readings or put them in code tags so they don't force people to scroll for ever to see the replies :)

Can you post a link to the sound sensor or a schematic?

Regards

Ray

The circuit for sound sensor is given in the link below:

Hi Kavish, I think you will get more replies if you edit the subject of this thread, to something like. "Help with sound level sensor readings." Members of the forum only look at the thread titles and usually only read those that interest them, or which they think they can be of help. A CAD or picture of a hand drawn circuit in jpg, png or pdf format will help, as well as your code. And the link or spec of the sound level sensor.

But first check here

http://forum.arduino.cc/index.php/topic,148850.0.html

to see how to post code and other information in your posts.

Hope to help. Tom....... :)

Kavish: The circuit for sound sensor is given in the link below: http://electronics.stackexchange.com/questions/57683/can-i-use-a-pnp-transistor-with-an-electret-microphone-to-get-an-non-inverting-o

What is the DC output impedance of C2 (0.1uF)? (Don't try to answer...) The Atmega A/D channels expect a impedance of 10K Ohm.

http://www.instructables.com/id/Arduino-Audio-Input/?ALLSTEPS Note how this circuit uses two 100K (50K DC impedance) to set the input DC reference to 1/2 the SAR reference voltage. This resistor network thus establishes the DC bias which the AC signal can "swing" against.

Here is the Sparkfun microphone breakout board schematic: https://www.sparkfun.com/datasheets/BreakoutBoards/Amplified-Mic-Electret-v14.pdf See the DC resistor bridge?

Ray

Hi Kavish

To add to the hardware examples posted by Ray, here is some Arduino code that will convert the analogRead results (which will fluctuate around (approx) 512) to a peak sound level reading, based on how far they fluctuate from the midpoint.

https://learn.adafruit.com/adafruit-microphone-amplifier-breakout/measuring-sound-levels

All the best

(another) Ray

That gradually decaying input can occur when the input is left floating, or pulled down through an extremely high impedance.

(another) Ray

OMG!

So, do we number, zero-based: Ray0 and Ray1? or, the traditional Ray1 and Ray2

Should we anticipate future collisions? If so, maybe Ray01 and Ray02... or Ray00 and Ray01?

I need another cup of coffee... 2 has not provided the required enthusiasm!

Ray