classroom noise level alarm

classroom noise level

Students explore Little Bits in order to create an helpful tool for the entire class.
Probably they will stumble upon the “loop” effect and they will learn how to work around to solve the challenge.
It was time that we got the need to invent something to help us to control the noise level in our classroom, so i proposed them to work it out using Little Bits.
They did and in a week the level of noise was perfect!!!

Duration: at least 2 hours

Elementary (ages 8-10)



buzzer 1
power 1
sound trigger 1
wire 3


STEP 1 : The challenge

Introduce the features of the alarm:
1. It has to alert us each time the noise produced by our voices, by the movement of the chairs, by the slumming door… is too much.
2. To be effective it has to bother us really a lot, it has to be some that we really don’t wanna activate.

STEP 2 : Design your project

classroom noise level1

This part can be done individually, in small groups. Students will understand very soon that they will need very few modules to make it up. The main point is that, for now, they will surely not consider some very necessary ones!

Students have to draw a project of the alarm with the modules they intend to use and, when all the projects are ready, they will discuss them one by one in order to choose the one or two that fit better to the task or in order to make a collective new project based on the ideas they present to each other.

This kind of discussions are very intresting for the teacher, while you are listening to them you can test:
*the accuracy of the terms they use to describe and to talk about a specific object
*how they delineate the trouble and the solution
* the level of abstraction they are able to handle
*if they choose a projet for some emotional reasons (friendship, for example) or if they are able to have some objective criteria to support their choices
Also for students this is a very important stage: they need to “sell” their idea as best as they can but they also need to be able to assume the critics of the schoolmates when they are correct.

STEP 3 : Testing and finding the trouble

classroom noise level2

In this step students will build the alarm and test it.
If it’s working fine at the very first moment, well, they are champions 😉

But probably it wont because they didn’t think about the “loop” effect and the alarm will continue to buzz and buzz.

So the challenge, now, will be to understand why. And this is not so easy for them as it seems. Probably you will need to guide them by posing them some “good” questions as:

– if the buzzer continues to buzz is because the sound trigger gets some information from the outside around, so which kind of information is the sound trigger catching?
Some of them will say: is the noise of the buzzer!!! So while the buzzer is buzzing the sound sensor will always detect a noise and this will never end. In this way they meet “the loop”. They can easily verify that if they use a led instead of the buzzer, the alarm works fine without stepping in loop. But the led doesn’t disturb and we wanted a very bothering alarm.

How to turn around this?

Leave them free to try a bit, but not too much: if they don’t get a solution in a rather short time it can be very frustrating.

You can give them some advises to make them understand that “distance is the solution”. Some like:

– what’s the difference in the level of sound if you scream in the ear of your friend and if you scream outside of the door?
– Can we figure out something to protect the sound trigger from the noise of the buzzer?
For sure they will step to the right solution: adding some wires between the sound trigger and the buzzer!

STEP 4 : Make it perfect

The last step is to calibrate the sensitivity of the sound trigger: you will need to try it several times in your classroom before to make it perfect for your needs.

But it will works fine and, in some days, you will see your students paying more and more attention about the noise they normally produce. And they will be proud of themselves for the alarm they invented and for having less noises to bother them during the lessons.

Also teachers will pay attention not to scream or to raise their voices too much and this will be a great satisfaction for the students 🙂 😉

We were counting each time the buzzer was activated: in only one week we passed from some like 25 buzzes in 2 hours to 2 or 3 maximum. When we were able to stay under the 3 buzz in 2 hours, each students got a reward in the diary.