Pioneer Distancing Alarm (PDA From Tunisia)

Context

Since the appearance and spread of COVID, we faced new problems that changed our daily lives: how to avoid being contaminated, how to disinfect our objects and food, how to wash hands without spreading the virus, how to keep distances in public places.

Indeed, since the return to school, the opening of cinemas and markets, the problem of social distancing is becoming increasingly important.

While advised people to keep a distance of 1 meter, we notice that more and more people forget to keep their distance or even more serious, they take the risk of mixing with other people without worrying of the problem.

In my 9th year class, we are learning computational thinking and problem solving using the Microbit chip.

This programmable chip allows us to imagine solutions to problems through the use of its properties (sensors, LED display, etc.)

It is in this context that my students started working to find solutions to the problems they encounter every day.

2 microbit

a Buzzer (per microbit)

crocodile clips for each microbit chip

The system can be placed in collar. For this, we can create a box that allows you to display the LED screen

The system can also be placed in a facial mask created with the origami techniques

The system can also be placed on a cap.

The problem

After a brainstorming session that collected students' ideas. We have agreed to solve the problem of social distancing.

How?

They set the goal to work in a group to solve the problem of social distancing.

We have formed groups of four students. Each group is interested in certain microbit properties by programming the sensors that are integrated there. Students expose their work and discuss the different ideas.

At first, we kept an idea where an ultrasonic sensor is used with the microbit: when the sensor detects an individual (an obstacle) at a distance less than one meter, a buzzer creates a sound and alert the presence of a person too close to the one who keep the system.

Quickly, we raised a system fault: the ultrasonic sensor does not make the difference between a human obstacle and an ordinary object (a wall, a table, a car, etc.). Therefore, this system may give a lot of false positives.

The solution

Subsequently, we explored another track: radio communication.

Indeed, by experimenting with the exchange of messages by radio waves, we realized that we could measure the strength of the radio wave signal.

Explanation

When two microbit chips start to exchange messages, we can measure the "Radio signal strength" property: If the microbit chips are "distant", the signal is considered low and if the microbit chips are "close", the signal is significantly high.

Note that the value of the signal strength is between -42 (very strong signal) and -128 (very low signal)

Eureka, I found it!

One carries a microbit that sends information through radiowaves. The signal strength is measured permanently. If the signal reaches a certain value, then the LED screen displays the image of a virus and the buzzer outputs a a beep. Otherwise, the LED screen displays an ‘yes’ icon

We measured the average distance for each range of radio signal. We concluded that the threshold -55 is adequate for our application

n.b.:

We have started our project using makecode for microbit. When I told them about instructables Microbit contest in association with tinkercad, they insisted to participate.

We have tried to find how to implement radio signal strength property but it still unfound. Consequently, pupils of Lake Banks Pioneer preparatory school (Tunisia) ask you to help them fix that issue by providing this option or to explain how to use it (if it exists).

My pupils liked TinkerCAD app and woud like to use it instead of using other apps. They also will use TinkerCAD to design their solutions in the future