Noise Pollution App | Sound Meter App MIT App Inventor | Sound Level | Noise Sensor MIT App Inventor

Summary

In this tutorial, the instructor guides viewers on creating a 'Noise Pollution' app using MIT App Inventor. The app leverages the phone's microphone as a sound sensor to measure decibel levels and assess noise pollution risks. It features a slider to represent sound intensity and a label to display decibel measurements. The tutorial covers downloading the necessary extension, setting up the app's interface, and coding the logic to update the UI based on sound levels, using color-coded indicators to signify different noise risk levels.

Takeaways

• 🎓 The video is a tutorial on creating a sound sensor app to measure noise levels in decibels and assess the health risks associated with different noise levels.
• 🔍 The app will utilize the sound sensor, essentially the phone's microphone, to measure sound intensity, which is not possible with the standard sound recorder component in MIT App Inventor.
• 📲 An extension is required for the sound sensor functionality, which is downloaded from a provided link and imported into a new MIT App Inventor project named 'noise pollution'.
• ⏱ The sound sensor extension is set to listen for sound every half second, as configured by the interval property.
• 📊 The app's user interface includes a slider, named 'sound level bar', to visually represent the sound level, with a disabled thumb to prevent user editing.
• 📝 A label, 'decibels label', displays the actual decibel measurement, and another label, 'sound description', provides information about the health risk associated with the sound level.
• 🛠️ The app requests audio recording permission upon initialization, which is necessary for microphone access.
• 📈 The app uses A-weighted decibels, a standard for assessing hearing damage and noise pollution, measured by the sound pressure level extension.
• 🌈 The app categorizes sound levels into different risk levels using color coding and descriptions, based on a simplified interpretation of a chart from Electronics Hub.
• 🔧 A custom procedure, 'update screen', is used to dynamically update the slider's position, color, and the sound description label based on the measured decibel level.
• ⚠️ The tutorial advises to disable screen timeout when testing the app to ensure continuous operation of the sound pressure level component.

Q & A

What is the main purpose of the app being discussed in the script?

The main purpose of the app is to measure noise pollution using a sound sensor and display the sound level in decibels along with health risk information.

Why does the instructor prefer not to use extensions in MIT App Inventor?

The instructor prefers not to use extensions because they believe that they can take away from the learning experience, as the goal is not just to make apps but to learn to code and prepare for other languages.

What is the sound sensor on a mobile phone?

The sound sensor on a mobile phone is the microphone, which is used to measure sound intensity with the help of an extension since the sound recorder component alone cannot do this.

What is the interval set for the sound sensor in the app?

The interval for the sound sensor is set to 500 milliseconds, meaning it will listen for sound every half second.

What is the significance of the slider component in the app?

The slider component is used to visually represent the level of sound or noise in terms of health risk, with the thumb position indicating the current sound intensity.

What are the three types of sound measurements provided by the sound pressure extension?

The sound pressure extension provides measurements in decibels, A-weighted decibels, and C-weighted decibels, with A-weighted decibels being used for determining hearing damage and noise pollution.

Why is it necessary to get permission for recording audio when using the app?

Permission for recording audio is necessary because the sound pressure level extension uses the microphone to measure sound intensity.

How does the app handle the display of the decibel measurement?

The app rounds off the A-weighted decibel value and displays it along with the unit 'dB(A)' in the decibels label for clarity.

What is the procedure used to update the app's screen based on the sound intensity?

The procedure called 'update screen' is used to set the slider's thumb position, update the sound description label, and change the color of the slider based on the A-weighted decibel value.

How does the app categorize different sound intensities in terms of health risk?

The app uses a simplified version of a chart from Electronics Hub, categorizing sound intensities into different risk levels such as no risk, normal sounds, busy traffic, loud radio, airplane or concert, and hearing damage.

What is the maximum value of the slider in the app and why is it set to this value?

The maximum value of the slider is set to 150, which corresponds to the highest sound intensity level considered safe before reaching the risk of hearing damage.

Why is it important to disable the thumb on the slider?

The thumb is disabled to prevent users from editing the slider's value, as the app is meant to automatically display the sound intensity level based on the microphone's input.

What is a potential issue to be aware of when testing the app on a device?

When testing the app, it is important to turn off the screen timeout because the sound pressure level component may stop working when the screen times out.

Outlines

00:00

🎙️ Building a Noise Pollution App

This paragraph introduces a tutorial on creating a sound sensor app to measure noise pollution in decibels using MIT App Inventor. The app will utilize a sound sensor extension to gather data from the phone's microphone, a slider to represent sound levels, and a label to display decibel measurements. The focus is on learning to code and preparing for other programming languages. The tutorial begins with downloading and importing a necessary extension, setting up the app's interface, and configuring initial properties.

05:02

🛠️ Setting Up the App Interface

The second paragraph details the process of setting up the app's user interface. It involves adding a slider and labels to the screen, configuring their properties such as color, size, and alignment, and disabling user interaction with the slider. The goal is to create a simple yet efficient screen design that will visually represent the sound levels and their potential health risks.

10:02

🔊 Implementing Sound Measurement Logic

In this paragraph, the script explains how to implement the logic for measuring sound levels. It involves obtaining microphone permissions, using the sound pressure extension to measure sound intensity in A-weighted decibels, and updating the app's interface based on the sound levels. A procedure called 'update screen' is created to handle the display of sound intensity, color coding, and risk descriptions based on predefined decibel ranges.

15:06

📊 Configuring Sound Level Risk Assessment

The final paragraph discusses configuring the app to assess the risk associated with different sound levels. It uses a simplified version of a sound intensity chart to categorize sounds into risk levels and update the app's interface accordingly. The tutorial also includes handling extreme sound levels beyond the slider's maximum value and provides a tip for testing the app to ensure the sound sensor remains active.

Keywords

💡Sound Sensor App

A 'Sound Sensor App' is a mobile application that utilizes the device's microphone to measure ambient sound levels in decibels. In the context of the video, the app is designed to not only measure sound intensity but also to inform users about the health risks associated with different noise levels. The script describes the process of creating such an app using MIT App Inventor, including the need for an extension to access the microphone for sound intensity measurement.

💡Decibels

Decibels (dB) are a unit of measurement used to express the intensity of sound. The video script discusses using the sound sensor to measure sound in decibels, which is essential for assessing noise pollution levels. The app being developed will display these measurements to users, allowing them to understand the potential health risks associated with the sound levels they are exposed to.

💡Slider Component

In the script, the 'Slider Component' refers to a user interface element that will be used in the app to visually represent the level of sound or noise. The slider will be updated based on the measured decibel levels, providing a clear and interactive way for users to see the current noise level relative to health risk categories.

💡Health Risk

'Health Risk' in the video pertains to the potential dangers that different noise levels pose to human hearing and overall health. The app will categorize noise levels into risk levels, using color coding and descriptions to inform users about the potential harm of the noise they are exposed to, as illustrated by the script's reference to sound levels similar to an 'airplane or concert' indicating a risk.

💡Noise Pollution

Noise pollution is the unwanted or harmful outdoor sound created by human activities, which can have adverse effects on the quality of life and health of people. The video's main theme revolves around creating an app to measure and display noise pollution levels, helping users to be aware of and mitigate the risks associated with high noise environments.

💡Microphone

The 'Microphone' is the hardware component of a mobile device that captures sound. In the context of the video, it is used by the sound sensor extension in the app to measure the intensity of sound. The script mentions that while the sound recorder component in MIT App Inventor is connected to the microphone, it cannot measure sound intensity, necessitating the use of an extension.

💡Extension

In the video script, an 'Extension' refers to additional software that expands the functionality of the MIT App Inventor platform. Since the base platform does not support direct measurement of sound intensity, the creator mentions downloading and importing a specific extension to enable this feature in the app being developed.

💡A-Weighted Decibels

A-Weighted Decibels (dBA) is a measurement of sound intensity that takes into account the human ear's sensitivity to different frequencies. The script emphasizes using dBA for the app because it is a standard for determining hearing damage and noise pollution levels, which is crucial for assessing the health risks of the measured sound.

💡Procedure

In the context of the video, a 'Procedure' refers to a set of blocks of code within the MIT App Inventor that performs a specific task. The script describes creating a procedure called 'update screen' that takes inputs such as color, sound intensity, and description, and updates the app's interface accordingly to reflect the current noise level and its associated risk.

💡Permission

The term 'Permission' in the script refers to the user's consent required by the app to access certain device features, such as the microphone for recording audio. The video explains that when the app initializes, it needs to request and obtain permission to use the microphone, which is essential for the sound sensor functionality.

💡Screen Timeout

In the video, 'Screen Timeout' refers to the setting on a mobile device that causes the screen to go dark after a period of inactivity. The script advises users to disable or extend the screen timeout when testing the app to ensure that the sound pressure level component continues to function without interruption, as the screen going dark could stop the app from measuring sound levels.

Highlights

Introduction to creating a sound sensor app to measure decibels and assess noise pollution.

Utilization of the sound sensor to measure sound intensity and the slider component for health risk visualization.

Explanation of the necessity for an extension when native features are unavailable in MIT App Inventor.

The sound sensor on a mobile phone is essentially the microphone, which is used for sound intensity measurement.

Instructions on downloading and importing the sound sensor extension for the project.

Setting up the project 'noise pollution' and configuring the screen properties for the app.

Adding and configuring the sound sensor component from the extension to the project.

Incorporating a slider to represent sound level and its configuration for the app's user interface.

Creating labels to display decibel measurements and sound descriptions for user understanding.

The importance of obtaining microphone permissions for the app to function correctly.

Using A-weighted decibels as a standard for assessing hearing damage and noise pollution.

Implementation of the sound pressure level updated event to dynamically measure and display sound intensity.

Developing a procedure to update the UI based on the sound intensity measured.

Using conditional logic to categorize sound intensity levels and update the app's UI accordingly.

Guidance on testing the app effectively by managing screen timeout settings.

Encouragement for viewers to like, share, and subscribe for more educational content.

Transcripts

foreign

[Applause]

[Music]

soft I will show you how to make a sound

Sensor app in today's class we will use

the sound sensor to measure the sound in

decibels and we will also use the slider

component to show the level of sound or

noise in terms of health risk so in a

way we will be measuring noise pollution

and showing our results using a nice

looking front end

let's begin by downloading an extension

I don't like using extensions that much

as I believe that they take away a large

chunk of The Learning Experience the

goal of my channel is not just to help

you make MIT App Inventor apps but to

make you learn to code and prepare you

for other languages like Java or python

however sometimes extensions become

necessary when a feature isn't available

in MIT App Inventor at all so what is a

sound sensor on a mobile phone yes you

guessed it right it is the microphone we

have the sound recorder component in MIT

App Inventor that is connected to the

microphone still unfortunately we can't

measure sound intensity with it so this

is why we need the extension so let's

download the extension first I will give

this link in the video description

just click here

and it will be downloaded to your

computer now open up MIT App Inventor

and start a new project let's call it

noise pollution

first of all go down until you reach

this part extension and import the

extension and choose the extension file

the AIX file that you downloaded

click on import

once it has been imported we need to add

a component of this extension so just

drag and drop it on to the viewer

so it has been added

and I am going to change this interval

to

500. okay

so this means it will listen every half

a second because this is in milliseconds

for screen One Properties

make a line horizontal Center and align

vertical Center

okay and the background color I'm going

to make it

dark gray

make screen orientation portrait

and change the title

to noise pollution

okay

now drag a slider

from user interface

onto the viewer

rename

sound level bar

change the default

color left to this blue color color

right should stay the same make the

width

95 percent

the max value is

150 the minimum value is 1 this is very

important we have to disable the this

thumb so uncheck thumb enabled because

we don't want the thumb to be shown and

we don't want it to be edited by the

user Changed by the user and the thumb

position is at one okay add a label from

user interface below this slider

rename to

decibels label this will show the actual

measurement of the decibels

make font Bowl font size 22

height is

15 percent

and just remove all the text from it and

the text alignment is Center and the

text color is white

okay now

select it and duplicate this component

this label by pressing Ctrl C Ctrl V for

Windows or command C command V for

MacBook

rename the second one

to

sound description

lbl this means this will show what

this sound means that is is it a risk

for humans or not and we're just going

to change the font size to 18 a bit

smaller okay

a simple but efficient screen design is

done so let's go to the block section

here what I'm going to do is that when

the screen is initialized

we want to get the permission for

recording audio because the sound

pressure level extension uses microphone

and we need permission for microphone

okay

so click on screen one and get its

initialize event and inside it

again go to screen one and get the ask

for permission

procedure and choose audio from here

okay now our sound pressure extension

this one measures sound intensity using

three types of measurements

decibels a weighted decibels and C

weighted decibels so we we will use the

a weighted decibels as a weighting is a

standard for determining hearing damage

and noise pollution okay

whenever the noise surrounding the

mobile phone changes we need to check

for the sound pressure level updated

event okay so just click on this sound

pressure extension

and get this event

inside it we are first going to show the

value of our a weighted decibels inside

our decibel labels but we will also

round It Off

so get the set block

set text block and inside here

I'm going to do actually a join

because I also want to show the unit

first one is the actual number but round

it off

so from mats

get the round block

and here

this is the

getter for

a weighted decibels

okay

and

here we are going to show in a text

block the unit

Okay so tap here and press the space bar

to give a space

and then write d

capital B and then in Brackets because

it's a weighted

so so this is the unit of a weighted

decibels okay

and next we are going to look at the

actual value of the a weighted decibels

and do a comparison and update our

slider accordingly okay this one

and I'm using a chart from Electronics

hub

this one

to decide what is the intensity of sound

which is dangerous okay so you can see

the color codes and we will be not using

the entire chart and we will be

simplifying it a bit okay

so first of all I am going to make a

procedure okay so go to procedures and

get this first one and I'm going to add

three inputs to it so click on this Cog

wheel and drag and drop

three inputs so the first input is the

color

okay

second input

is the value of the actual

sound intensity in decibels a weighted

decibels and text is the description for

r

sound description label and we will be

actually inside an if else block we will

be calling this procedure again and

again and let's call this procedure

update screen

what will this procedure do first of all

it will set the sliders thumb position

to the to the value

it will

set the description

so

this one

to the text

okay

and

it will

set the sliders I can actually duplicate

this one

and change this to

color left

and this is the color okay so these are

the three three things that need to be

updated depending upon the actual value

of the a weighted decibels okay and we

have put this inside a procedure so that

we just send the three values to our

procedure

and it will update it accordingly okay

so now I need to add some if else blocks

here whenever the sound pressure level

is updated so if I go to control I need

the third one

okay let me organize my code click on

cleanup blocks and I need this is one

two three I actually need three more

else if okay so drag and drop

so just one more okay okay you can

remove some extra ones

if you accidentally add them okay

okay so what is the first if

the first if is

when DBA

ited decibels is less than or equal to

30. this means it is very quiet in

similar to a recording studio so we will

call our update screen procedure with

all this input Okay so so I'm going to

first of all from maths get this equal

to block and here I'm going to choose

less than equal to and again from maths

I'm going to get this block this is

30 and here what is this this is a

weighted decibel so I just duplicate

this and put it here so if

DBA a is less than equal to 30 I am

going to call my procedures this update

screen procedure with what with the

color so what is the color I am going to

give it a light blue color so if I could

click on colors and can get this

light blue color to it

so an aqua color and what is the value

the value is the a weighted decibel so I

can duplicate that and what is the text

now

let's click on here and here I'm going

to type in

something that can be understood by a

user that this is no risk

and it is similar to a recording

Studio

okay now again I can duplicate this

condition and choose now instead of less

than equal to 30 I'm going to choose 70

here and I'm going to call

this procedure so just duplicate it and

here I'm going to change the color to

green

and here it is no risk

but

and normal sounds

okay

now

let me clean up my code again let me

take it a bit down because

this is getting up

a bit

jumbled up okay again duplicate

bring it down now it's less than equal

to 85

and I am going to call my procedure

I'm going to change this color

to a bit

dull

green

okay and here I'm going to say no risk

but traffic

busy traffic or

loud radio okay

so again I'm interpreting that chart the

electronic sub chart in my own way you

can you know make it more detailed and

add more information if you want okay

again I'm going to duplicate this

condition

and I'm going to choose one

120 here so change it to 120 now

this is where the risk is starting so if

I duplicate this and bring it here I'm

going to change the color to now or

range

okay and this is a risk

and this is a airplane or concert

now let's again duplicate and this one

is now less than equal to 150 now this

is

the max value of our slider so I'm going

to call

my procedure and make this red and this

is hearing damage okay

and most probably probably if it is so

loud this means that this is an

explosion

okay

so now what comes in else it means that

now the a weighted decibels is a value

that is even greater than 150 so

which is kind of

technically impossible and unrealistic

but still we have to consider that

situation and we're just going to call

this

update screen procedure again and I'm

going to change the color to even a

darker shade of red but instead of

sending it the actual value because

remember a slider's maximum value is

150. so what we're going to do is we are

going to send it the max value of our

slider so if I click on my sound level

bar

I can get its max value and I'm just

going to tell it that okay just fill it

up completely okay

and

a text is that

it is extremely high risk I mean I can't

think of anything which is louder than

an explosion so I'm just going to call

it

extremely

High

risk okay

also please change this to get text

because I just noticed that they were

both get value here so this should be

get text okay

the sound description label okay and

another important thing is that when

you're testing the app using the

companion or by installing it on your

devices make sure that you turn off your

screen timeout because every time the

screen will time out

the sound pressure level component will

stop working so make sure that you

either turn off screen timeout or make

it a long period of time after which it

times out okay so I hope you will have

fun making this cool app and checking

out the sound around you too to see

whether it is a risk or not please like

my video and please share it with your

friends and family and if you haven't

subscribed to my channel kindly do so so

that you don't miss any of the great

projects that I have planned for you

thank you for watching my video have a

good day and goodbye