Lights Out; Physical Considerations - sparkfun SEN-12642 Hook-Up Manual

It's most likely that you'll find the detector to be too sensitive. In testing the board for this writeup, noisy air
conditioning and music in the next office were enough to set it off. To make the board less sensitive, you can lower
the preamplifier gain by populating R17 in parallel with R3.
R3 Value
Raising The Gain
If you want to make the sound detector more sensitive, so that it will be activated by quieter sounds, you can
remove R3, and populate R17.

Lights Out

In some applications, the onboard LED may be distracting or undesirable. To disable it, simply use a solder sucker
or wick to remove the solder blob from the jumper near the LED.

Physical Considerations

The electret capsule on the Sound Detector is also sensitive to mechanical vibration and wind noise.
The Sound Detector will pick up handling noise. Mounting it with a resilient material can help absorb vibration –
placing it on a piece of open-cell foam helped reject vibration conducted through the testing workbench. Other
resilient mounting strategies would include suspending it using rubber bands, or building shock absorbers using #4
machine screws and heat-shrink tubing.
Wind noise is caused when blasts of air enter the capsule. Examples would be a windy day, or the sharp
exhalation that often accompanies syllables such "p," "b" and "t." The capsule come with a thin fabric covering, but
it may not be enough to prevent stronger blasts. You can craft a more robust windscreen with open-cell foam or
R17 Value
100K -
100K 100K
100K 47K
100K 22K
100K 10K
100K 4.7K
100K 2.2K
R17 Value
100K
220K
470K
1Meg
Arithmetic Gain
100
50
32
18
9
4
2
Arithmetic Gain
100
220
470
1000
Gain (dB)
40
33
30
25
19
13
6
Gain (dB)
40
46
53
60