My MAX9814 Electret Micropohone results fail so far

rq3

Senior Member
Hi,

Great little test program hippy, thanks ... here's the data I got back ... seems the louder the noise (my parrot Poncho Villa) the lower the minimum ??? the higher the maximum.

Min = 53 Max = 61
Min = 53 Max = 62
Min = 53 Max = 70
Min = 53 Max = 76
Min = 53 Max = 79
Min = 50 Max = 79
Min = 50 Max = 80
Min = 46 Max = 80
Min = 46 Max = 81
Min = 46 Max = 83
Min = 43 Max = 83
Min = 43 Max = 86
Min = 41 Max = 86
Min = 41 Max = 89
Min = 41 Max = 93
Min = 41 Max = 95
Min = 39 Max = 95
Min = 34 Max = 95
Min = 29 Max = 95
Min = 29 Max = 99
Min = 24 Max = 99
Min = 24 Max = 104
Min = 24 Max = 109
Min = 23 Max = 109
Min = 20 Max = 109
Min = 20 Max = 130
Min = 13 Max = 130
Min = 7 Max = 130
Min = 0 Max = 130

The higher max (Poncho) is still not as loud as the lobby area when there's a party going on, but he can get pretty loud.

I changed the range in the other DO LOOP to; loop Until w0 <= $1F or w0 >= $12C

But get this data ??? [1F] [1B] [1A] [1B] [1B] [18] [1D] [1F] [1F] [1F] [1E] [1B] [1D] [1F] [1F] [1E] [17] [12] [1E] [16] [18] [18] [18] [1E] [01] [1D] [1E] [1E] [19] [1D] [1F] [1E] [1C]

The red LED turns ON with no sounds and the program delivers the [hex codes] until there's a sound then I get the decimal number [18], [17] [12], [16] [18] [18] [18] hence if I create an action besides the red LED it will occur between sounds.

Looks to me like you're home free.

If Max>110 then
do something
endif

All you have to do now is make a Picaxe powered parrot pleaser, so that Poncho squalks when you press a button. I have no idea what it takes to please a parrot. Perhaps responding to an LED? That would be an interesting feedback loop!

I understand most parrots have pretty good color vision, at least in the red and ultraviolet.
 
Last edited:

hippy

Senior Member
Great little test program hippy, thanks ... here's the data I got back ... seems the louder the noise (my parrot Poncho Villa) the lower the minimum ??? the higher the maximum.

Min = 53 Max = 61
:
Min = 24 Max = 99
:
Min = 0 Max = 130
That seems about right. When you started it was probably silent (53,61) which is roughly the 1.25V 'silence' one would expect.

As sound increases the minimum decreases as the peak moves towards 0V one side and maximum increases as it moves towards 2.5V the other. The final reading (0,130) shows that, maximum volume reaching maximum values expected.

It's then just a matter of choosing a minimum below which sound is present, a maximum above which sound is present.

If you want to detect noise which is above any particular ambient you will need to track an average low ( and/or high ) and then look for changes which are significant below ( or above ) those values.
 

AllyCat

Senior Member
Hi,

The average output (bias) level now appears to be around 57 (but drifts upwards at higher sound levels, indicating some non-linearity even before the ultimate clipping at 0). However, the average for the data in post #26 was 69, possibly due to the supply voltage being different. Therefore, you may need to use a stabilised supply (ADC reference voltage), or some other form of calibration method, for reliable long-term performance.

Cheers, Alan.
 
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