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.Can anyone help me finding a circuit diagram for this room noise detector, my professor happen to assign this to our group, he told us to provide our circuit and having this output, the led array display, please help, or even a simple buzzer. THANKYOU!
Think about using a microphone (or other pickup device) to monitor room noise. Amplify the signal and drive something like a LM3914. I suggest you Google the LM3914 and read the data sheet. That would be one approach anyway.
Additionally these forums have a section for homework and schoolwork.
An LM3914 is a linear voltmeter not suitable for measuring sound levels which are measured in decibels. An LM3915 should be used instead and has the measured levels 3dB apart.
An LM3914 is a linear voltmeter not suitable for measuring sound levels which are measured in decibels. An LM3915 should be used instead and has the measured levels 3dB apart.
The OP made no mention of wanting perfection, just a display. Yeah, nice 3 dB steps and how would they calibrate it? Hell, I say use the LM3914 and be done with it. Besides the OP never came back... Oh well.
An LM3914 will have loud noises crammed into the top few LEDs less than only 1dB apart and low level sounds will not be displayed.
Medium sound levels will have their spacing different from one LED to another.
From LED1 to LED 2 the spacing will be double the level (+6dB).
An LM3915 has exactly 3dB between any 2 LEDs which is a small amount but is heard. The total of 10 LEDs is 30dB which is a good range of levels.
Borrow a real sound level meter to calibrate this one.
OK, then I concede. Use the LM3915, on the off chance you return. The LM3914 would give a linear representation where the LM3915 will give a true logarithmic representation of the audio level in the room. I just see the difference between the first and last LED driven by a LM3915 as really loud.
One LM3914 shows a range of only 20dB which is not much from soft to louder.
ONE LM3915 shows a range of 30dB which is more but not much more.
TWO LM3915 ICs in series show a range of 60dB which is soft to loud. The Sound Level Indicator project in my living room has a range of 50dB and shows almost all sounds there.
THREE LM3915 ICs in series show a range of 90dB which is soft to very loud.
Many people can hear a loudness range of 120dB.
I don't like guns and I like to keep my hearing so I have never heard a loudness more than 120dB (which I measured in a disco).
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