Topic outline

  • General

  • PRESENTATION




  • ACTIVITY DESCRIPTION

    The idea is to make the students aware of the insalubrity the noise produces and also the amount of it they emit everyday at school.


    In order to do that, the mBot robot will be programmed as a “mobile soundmeter”, which will evaluate the sound level emitted by the students in every classroom, to find the noisiest one.


    Also, the second part of the activity consisted in solving the problem the sound level meter and the sound sensor had. We have achieved the mBot will calculate the decibels that are being emitted at the moment the measurement is taken.


    Absolute maximum concept.The student will be able to calculate the sound decibels or the decibels of an environmental noise. From these calculations they will be able to know in what range of the scale of decibels is the sound emitted.


    The mBot robot has to be programmed to take measurements of noise in different classrooms. Later the robot will inform about the noise levels reached and about how unhealthy noise is.


    The sound sensor of the mBot measures the environment, no the decibels of sound. We need to create a program that can measure the decibels.


  • FIRST VERSION

    The activity consists on programming a mBot assisted by a laptop, whose function will be to move in between the different classrooms informing about how unhealthy noise is and taking acoustic measurements. Its reaction to silence will be positive; on the contrary, it will react in a negatively from a certain noise level on.


    Once it has taken some measurements, the mBot will inform the students about the maximum sound quantity emitted. In this way a small competition between classrooms may be done, in order to check the most sound-efficient one.



  • SECOND VERSION

    The decibel (dB) is the measure with which we quantify the intensity of the sound.


    It is the relative unit used in acoustics, electricity, telecommunications and other specialties to express the relationship between two magnitudes: the magnitude being studied and a reference quantity.


    Thanks to this measure, we can know which auditory thresholds can damage our hearing. On the other hand, we must bear in mind that it is not only the intensity that determines whether a noise is dangerous: it is necessary to control the time that we expose ourselves to it.


    In this image, we can see the decibels scale and how we can be affected by the decibel level:




    A person can hear up to a maximum of 150 decibels: If the sound goes beyond this limit, it could cause irreversible auditive loss in the person.


    There are several decibel scales, but we will use the dbA, which is the one that measures the ambient sound.


    For the activity, we want that the mBot calculates the decibels of the site where we are. The Sound Sensor calculates an environmental value, so we need to convert that value to decibels.


    Once the sound level meter was calibrated, we had to find the formula for our mBot to calculate the decibels. After many tests/errors, we determined that if we divided the value obtained (by the Sound Sensor) by 3.3, we obtained the same result as in the sound level meter, so we managed to solve the problem of decibel detection.



  • ACTIVITY RESOURCES

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