## Introduction: SCHOOL BAG WEIGHT

Everyone has had a backache and knows about how annoying and painful can be, so why not designing a way to avoid them?

The School Bag Weight is a project made with Arduino that consists in a wearable that alarms you if you bring too much weight on your bag. The goal is to create a system to avoid back injuries that could be integrated into the body in the near future.

This wearable simulates the electronic to be integrated in the body and uses pressure sensors and vibrators to get and transfer the information.

## Supplies

The electronic supplies used to make the prototype are:

- Arduino UNO (x1): The plate where the code is stored.

- Protoboard (x1): The board where the components are placed and are electrically connected to each other.

- Pressure sensor (x2): The sensors that detect the weight of the bag.

- Vibration motor (x5): The motors that vibrate when there is too much weight.

- Cable: Used to connect the components to the protoboard.

- Tin thread: Used to join the cable to the protoboard. The prototype supplies are:

-T-shirt: Element used to imitate the skin of human's body.

- Padded fabric: Cloth used to indicate the parts where the vibration is going to be activated. - Thread: Used to sew the padded fabric to the t-shirt.

-Velcro.

## Step 1: Assemble the Circuit

The function of project it is to warn the user when is carrying too much weight in the bag and can be harmful.

For this reason we have used two principal components:

- The pressure sensor detects the force applied in the area. This component needs a resistance, a pin in the ground and another in the 5V from the Arduino.

- The vibration motor is the responsable to warn the user through vibration. It is connected to a pin and the ground.

## Step 2: Code

//María Diz & Gabriela Iraola. Arduino
final project. Grup 102.

int AnalogPin = A0; // Pressure sensor connected to Analog 0

int AnalogPin2 = A1; // Pressure sensor connected to Analog 1

int motorVibracion1 = 10;// Vibration motor connected to pin 10

int motorVibracion2 = 9;// Vibration motor connected to pin 9

int motorVibracion3 = 8;// Vibration motor connected to pin 8

int motorVibracion4 = 7;// Vibration motor connected to pin 7

int motorVibracion5 = 6;// Vibration motor connected to pin 6

int sensor1; // The resistance of the sensor 1

int sensor2; // The resistance of the sensor 2

void setup()

{

Serial.begin(9600); // Send information to the serial monitor

//We define the vibration motors as inputs and their respectives pins:

pinMode(motorVibracion1, OUTPUT);

pinMode(motorVibracion2, OUTPUT);

pinMode(motorVibracion3, OUTPUT);

pinMode(motorVibracion4, OUTPUT);

pinMode(motorVibracion5, OUTPUT);

}

void loop()

{

sensor1 = analogRead(AnalogPin); // The resistance is equal to the reading sensor (Analog 0)

Serial.print("Lectura Analogica = ");//This will be printed in the screen

Serial.println(sensor1);

Serial.println(sensor2);

if (sensor1 >= 400 || sensor2 >= 400) { //If the force is equal or higher than 400 then the sensors are activated.

digitalWrite(motorVibracion1, HIGH);

digitalWrite(motorVibracion2, HIGH);

digitalWrite(motorVibracion3, HIGH);

digitalWrite(motorVibracion4, HIGH);

digitalWrite(motorVibracion5, HIGH);

delay(500); //For the vibration during longer

} else {//if not then they will be diactivated.

digitalWrite(motorVibracion1, LOW);

digitalWrite(motorVibracion2, LOW);

digitalWrite(motorVibracion3, LOW);

digitalWrite(motorVibracion4, LOW);

digitalWrite(motorVibracion5, LOW);

}

}//María Diz & Gabriela Iraola. Arduino final project. Grup 102.

int AnalogPin = A0; // Pressure sensor connected to Analog 0

int AnalogPin2 = A1; // Pressure sensor connected to Analog 1

int motorVibracion1 = 10;// Vibration motor connected to pin 10

int motorVibracion2 = 9;// Vibration motor connected to pin 9

int motorVibracion3 = 8;// Vibration motor connected to pin 8

int motorVibracion4 = 7;// Vibration motor connected to pin 7

int motorVibracion5 = 6;// Vibration motor connected to pin 6

int sensor1; // The resistance of the sensor 1

int sensor2; // The resistance of the sensor 2

void setup()

{

Serial.begin(9600); // Send information to the serial monitor

//We define the vibration motors as inputs and their respectives pins:

pinMode(motorVibracion1, OUTPUT);

pinMode(motorVibracion2, OUTPUT);

pinMode(motorVibracion3, OUTPUT);

pinMode(motorVibracion4, OUTPUT);

pinMode(motorVibracion5, OUTPUT);

}

void loop()

{

sensor1 = analogRead(AnalogPin); // The resistance is equal to the reading sensor (Analog 0)

Serial.print("Lectura Analogica = ");//This will be printed in the screen

Serial.println(sensor1);

Serial.println(sensor2);

if (sensor1 >= 400 || sensor2 >= 400) { //If the force is equal or higher than 400 then the sensors are activated.

digitalWrite(motorVibracion1, HIGH);

digitalWrite(motorVibracion2, HIGH);

digitalWrite(motorVibracion3, HIGH);

digitalWrite(motorVibracion4, HIGH);

digitalWrite(motorVibracion5, HIGH);

delay(500); //For the vibration during longer

} else {//if not then they will be diactivated.

digitalWrite(motorVibracion1, LOW);

digitalWrite(motorVibracion2, LOW);

digitalWrite(motorVibracion3, LOW);

digitalWrite(motorVibracion4, LOW);

digitalWrite(motorVibracion5, LOW);

}

}

## Step 3: Prototyping

The steps to make the prototype are:

1. Take measures of your lumbar and cervical and cut the padded tissue so that two layers can be made. This is because it will be used later as a wrapper to place all the components. The cervical and lumbar are the areas that suffer the most when too much weight is loaded, for this reason we want them to be protected.

2. Sew the padded tissue in order to obtain two cushions. Only sew the base and the two sides. In the upper side sew a velcro in order to open them and place inside the components.

3. When you have obtained the two cushions sewn with the velcro, sew them to the cervical and lumbar part of the back and inside of the t-shirt. You can sew them in the seams of the t-shirt so you can not see the seams on the front side of the t-shirt.

4. Weld the components in a plate so they will not move and get disconnected. You can also add insulating tape in order to ensure that the cables will not disconnect.

5. Place the components inside the cushions. All the components will go inside the cushions except for the pressure sensors:

5.1. Make sure that in the shoulders are the pressure sensors because it is where the bag makes contact.

5.2. Place two vibrating motors in the cervical and three in the lumbar.

5.3. Place the Arduino board and the welded plate in the cushion of the lumbar. This is because is the bigger one. In case of using an external battery, it will go here too.

6. Warn t-shirt weighing done!

## Step 4: Reflection of the Project

The objective of this project is to create a wearable for the human being that facilitates daily activities. In order to do this, we put forward different proposals in which people would receive more information than we can up to now, by means of technology inside our body.

Finally we think about the problems we have in our body due to lack of information and we create a method in which, through two force sensors placed on the shoulders, detecting the amount of weight you carry, warns us that we are carrying too much weight on our back, the warning signal being the vibration motors.

To simulate the process we took a flesh-colored T-shirt that simulates the human skin, and in the back part we built the whole circuit, keeping all the components in a pocket that we created with padded fabric to make the whole area comfortable.

In this project we have expanded our arduino knowledge through new components that we previously did not know, vibration motors and force sensors.