Computer Science Project

 

 

Data Recorded

 
Sec. Min. Hours
98888 1648,133 27,46889

The system recorded over 28 hours from Sunday 18.00 to Monday 21.00. In steps of 2 seconds were obtained 49444 records. I have used Excel to record data and make the necessary calculus.

Time Noise  
Seconds Volt  
    ABS
0 0,015 0,015
2 0,007 0,007
4 0,01 0,01
6 0 0
8 0 0
10 0,015 0,015
12 0,015 0,015
14 0,012 0,012
16 0,015 0,015
18 0 0
20 0,01 0,01
22 0,005 0,005
24 0,01 0,01
26 0,005 0,005

                                ...

98858 0,012 0,012
98860 -0,007 0,007
98862 0,005 0,005
98864 0,083 0,083
98866 0,007 0,007
98868 0,01 0,01
98870 -0,037 0,037
98872 -0,022 0,022
98874 0,01 0,01
98876 0,007 0,007
98878 -0,032 0,032
98880 0,029 0,029
98882 0,037 0,037
98884 0,002 0,002
98886 0,005 0,005
98888 0,015 0,015

 

  I have used an ABS function to convert some of the negative values of the list. This negative values result from a problem of the system related with the stability of the power supply. From this values I have made an average by hour and the result was:

Hours

Hours average

18(Sunday) 0,023753
19 0,024513
20 0,023182
21 0,022764
22 0,023053
23 0,02204
24(Monday) 0,018866
1 0,015791
2 0,015156
3 0,015227
4 0,01528
5 0,018223
6 0,020939
7 0,029987
8 0,035585
9 0,035222
10 0,03116
11 0,027196
12 0,02713
13 0,023922
14 0,031205
15 0,027856
16 0,0283
17 0,035649
18 0,035115
19 0,034918
20 0,030483
21 0,028713

In the values represented by a graph we can see the  evolution of noise over several hours.

                Fig.1 Noise evolution

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Searching & Reading

 After   recording  voltages with the ADC and make some the relations with noise itís important to know what noise in dB we have in the street and in special in the recording data that I have made last week. I found a site   where we can see the intensity of noise and the traffic in a street. In this video we can see the correspondence between 70dB to 80dB and the traffic in the street. ( Video)  

 In the graphic of Fig.1, the 0,035 Volt must correspond to 70 or 80dB, if we consider this relation we can found a table like the Fig.2. I hope to make some tests with a real decibel meter to confirm this results.

Hours Volts Noise  
18 0,024 54 dB
19 0,025 56 dB
20 0,023 53 dB
21 0,023 52 dB
22 0,023 52 dB
23 0,022 50 dB
24 0,019 43 dB
1 0,016 36 dB
2 0,015 34 dB
3 0,015 35 dB
4 0,015 35 dB
5 0,018 41 dB
6 0,021 48 dB
7 0,030 68 dB
8 0,036 81 dB
9 0,035 80 dB
10 0,031 71 dB
11 0,027 62 dB
12 0,027 62 dB
13 0,024 54 dB
14 0,031 71 dB
15 0,028 63 dB
16 0,028 64 dB
17 0,036 81 dB
18 0,035 80 dB
19 0,035 79 dB
20 0,030 69 dB
21 0,029 65 dB

Fig.2 Noise evolution(dB)

Video

References:   Univ.New South Wales , Noise meters

JM Freixo Nunes © 2009