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How to make baby cry alarm


#1

hi,
bought sound detection sensor is bellow. connected analog an0 port and read sensor data but its not return sound level correctly. is that possible a faulty?

http://www.aliexpress.com/item/Sound-detection-sensor-module-sound-sensor-smart-car-For-Arduino-dedicated/721642156.html

what is sensor i needed to the best way to detect sound level like a 0,20,100 data? thanks


#2

What do you mean by levels are not correct?


#3

First, make sure you are not putting more than 3.3V into the analog input. Since you are putting 5V into the sensor, it is likely the peaks exceed the 3.3V limit. A voltage divider will fix this.

To convert the voltage into DB, you are going to have to calibrate the sensor. You will need a sound source of known output, and then develop a table of sound level to input voltage. You can then do some math magic to get a voltage to DB formula for the sensor. The formula will be logarithmic.

You might be able to find the conversion formulas on the datasheet for the sensor chip.

Viola


#4

Hi mike, i do not understand you complately. wired 5v to sensor and read data but data is not sensitive. its return always a same value(28) not in a range like a 0-100. and it only return value when clap sound. tried some calibration values but it’s seems my new sensor is faulty. i guess i am wrong. which code sample am i use used code sample link is bellow.

https://www.ghielectronics.com/community/codeshare/entry/104

thanks


#5

It’s not an analog output.

Another page for this board show that is uses an LM393 which is a comparator. The POT on the board allows you to set the level at which the comparator will trip when the sound reaches this level.

This means the output will go from 5V with no sound detected, to 0V when detected.


#6

Him, that meant to only one signal can i detect. So i can not read range of sounds reached level. Thats not good for me because lowest pot level is not enough for me. Ok, thanks