Design And Implementation Of A Body Mass Index (BMI) Machine Using Load Cell And Ultrasonic Sensor

1.0 INTRODUCTION
Body Mass Index, can approximately calculates the total fat of the person present in the body. BMI is based on the two variables such as height and weight of the person. Even tough, the BMI does not give an exact measurement of total body fatness but according to many researches on BMI, one thing is clearly obtain that it is correlated with total body fat like other methods of body fat calculation, such as dual energy x-ray absorptiometry and underwater weighing techniques (Orlistat Xenical Philippines, 2014).
BMI is a widely used method compared to other body fat detection techniques due to its inexpensiveness and ease of calculating health risks related to obesity.
In this work a body mass index machine was built using load cell and ultrasonic sensor. The load cell or a weighing mechanism, which is used to calculate the body weight of a person, and an ultrasonic is used height calculating mechanism, which is use to calculate the height of a person. The weight of the person is calculated in Kilograms and the height in meters in accordance of the BMI standard formula (Wesley, 2013).
The microcontroller based automated Body Mass Index calculator is a useful device when it comes to controlling your weight and maintaining a healthy life style. The calculated weight of the person through load cell, converts the mechanical force into electrical signals that can be easily obtain after processing through microcontroller. While the height of the person is calculated by the ultrasound sensor with built-in transmit and receive circuitry as when it transits the ultrasound signal by transmitter, it reflect back to the receiver after striking the object or person and height is then calculated by multiplying the speed of the ultrasound signal and the time taken by the it to return back to the sensor. All this data is manipulated through microcontroller and then the result is displayed on the LCD display (Wesley, 2013).
The aim of the project was to design a BMI unit which gives numeric value and this numeric value gives a percentage which correlates to the body fat composition. If the numeric value is less than 20, the person will consider as underweight and person will be considered healthy it the value lies between 20 and 25. Above 25 is considered as overweight and above 35 is considered as Obese. In such case we require a precise instrument to calculate percent body fat like immersion tank. Two people having same weight might not float on the same level due to the difference in Body fat composition. BMI is useful tool for health related professional and investigators in some cases where risks of death are high for the overweight person, one extra pound can put a person on critical situation. People with coronary heart problems are one of them. Fat in our body increases which blocks the veins and arises different problems. The automatic or the electronic body mass calculator could be a useful tool to overcome the margin of errors (Jonathan Marker, 2014).

1.1 BACKGROUND OF THE PROJECT
Overweight and obesity are defined as abnormal or excessive fat accumulation that may damage health. Body mass index (BMI) is a simple index of weight-for-height that is commonly used to classify the two. The World Health Organization definition is that a BMI greater than or equal to 25 is overweight, and a BMI greater than or equal to 30 is obese.
According to the World Health Organization stated on August 2014 article, worldwide obesity has nearly doubled since 1980.In 2008, more than 1.4 billion adults, 20 and older, were overweight. Of these, over 200 million men and nearly 300 million women were obese. Sixty five percent of the world’s population living in countries where overweight and obesity kills more people than underweight. More than 40 million children under the age of 5 were overweight or obese in 2012.These two are the leading risks for global deaths. Around 3.4 million adults die each year as a result of being overweight or obese. In addition, 44% of the diabetes burden, 23% of the heart disease burden and between 7% and 41% of certain cancer burdens are attributable to overweight and obesity (Jonathan Marker, 2014).
In the Philippines, a 2011 survey by the Food and Nutrition Research Institute (FNRI) showed that 22.3% of Filipino adults were overweight, and 6.1% were obese. The FNRI-DOST also stated that the problem of obesity was increasing in an alarming rate in the Philippines where 7 out of 10 women and 1 out of 10 men were affected. The occurrence of overweight Filipinos is expected to increase significantly by 2015, which means more health problems ahead. According to the World Health Organization, obesity kills 2.8 million people worldwide while in the Philippines, it accounts for 37,000 deaths annually according to FNRI-DOST (www.loadstarsensors.com/what-is-a-load-cell.html).
Based on the data gathered by the proponents of the Microcontroller based BMI calculator with Database and Monitor Display,126 TUPT students as the respondents, female students have higher percentage of overweight, obese class 1 and underweight; and lower percentage of normal weight compared to male students. Normal weight percentage for female students was 61.91% only compared to male students having 77.96%. Overweight percentage for female was 28.57% while 15.25% for male. Underweight and obese class1 for women was 4.76% while 3.38% only for men (Jonathan Marker, 2014).
With those collected information, it only shows that most people are not conscious about their health status. Thus,the researchers decided to propose a new version of an automated Body Mass Index calculator by the aid of a microcontroller. It is designed to help obese, overweight and underweight persons to monitor the BMI and its classification. This will also benefit the users to be more aware of possible health diseases that can lead to death because of overweight and underweight conditions (Jonathan Marker, 2014).

1.2 PROBLEM STATEMENT
Over-weight is a problem in our society today which is mostly found in among women. Overweight and obese individuals are at increased risk for many diseases and health conditions, including the, high blood pressure, high LDL cholesterol and low HDL cholesterol, diabetes, plaque in arteries of heart, heart Stroke, gallbladder infection, degenerative joint disease, respiratory problems, and breast cancer. The worst side of overweight is that people who are over-weighted don’t know when they got to such level of weight. BMI is only an approximation for determining potential weight problems but it cannot be used as a diagnostic tool. A person will be on a great risk if they have a high BMI. Through these measurements physician can recommend different health risk related to weight. For example Skin fold measurements, fitness of a person, nutritionist can decide the diet of a person, and other screening of person’s health. However, the invention of this device is to help the user monitor their weight on their own without visiting hospitals (Rachelle A, 2014).

1.3 AIM OF THE PROJECT
The aim of the project was to design a microcontroller based automated Body Mass Index (BMI) calculator with LCD display, which calculates the body mass index using the two basic parameters that are weight and height which also gives numeric value and this numeric value gives a percentage which correlates to the body fat composition using load cell and ultrasonic sensor.

1.4 OBJECTIVES OF THE PROJECT
At the end of this work, student involved shall be able:
i. To calculate the body mass index electronically
ii. Study and understand the function and working principle of the load cell and ultrasonic sensor.
iii. To build a device that replaces the old method of calculating a body mass index.
iv. To test and assess the accuracy, reliability and functionality of the device including every parts and components used.

1.5 PURPOSE OF THE PROJECT
The purpose of this work is to provide a fast, reliable and displayable means of measuring body mass index.

1.6 APPLICATIONS OF THE PROJECT
The automatic Body mass index calculator has many applications in the vast field of biomedical engineering. Biomedical engineering is about the application of engineering in the field of medicine. The electronic BMI is such a device which is used in Hospitals, Clinics, and even Pharmacies. It can be placed at Gyms, Airports, Hotels, Bus Stands and other social places as well. Obesity as we all know is the leading cause of death nowadays, either directly or indirectly. And BMI is the most convenient and most efficient measure of obesity. Our particular project aims to provide a further convenient way to measure BMI as it removes the hassle of calculations. It can also be used for commercial purposes by installing a fool proof coin acceptor system.

1.7 SCOPE OF THE PROJECT
BMI machine is a modern, elegant, and importantly an accurate electro medical device that will measure one’s height and weight in just a matter of a minute. Its main features are as, measuring of height and weight, Calculates body mass index, displays the output on the LCD screen, easy to operate with minimum user interactions, accurate results.

1.8 METHODOLOGY
In building this project, the abstract, block diagram and the working principle of the project was studied, followed by drafting out a schematic diagram and arrangement the entire materials / components on the vero board, testing the completed system to see if the design works and finally, implementation of design of the project. The block diagram of the work is as below:

1.9 LIMITATION OF THE PROJECT
1. The maximum height that the ultrasonic sensor can detect is up to 7 feet or 2.13 meters only.
2. The maximum weight that the load cell can measure is up to 770 pounds or 350 kilograms.
3. The device is not applicable for people who cannot stand alone.

1.10 SIGNIFICANCE OF THE STUDY
This study is worth pursuing because of its capability to provide a device as medical equipment (Stacy Liong, 2011). This will benefit the following:
University Clinic: This study can help the University Clinic by providing a device that can accurately measure the height and the weight of a student, automatically calculate the BMI of the user, and easily determine the body status.
Professors / school: This study can help the Physical Education (PE) Professors or schools by providing equipment that can automatically calculate the BMI of a freshman student during PE1 subject.
Students: This study can help students who are health conscious to monitor their body mass status.

1.11 DEFINITION OF TERMS

 Body Mass Index – is used for measuring approximate total fat of a person present in the bodybased on their body weight and stature height.
 Load Cell – is a sensor that detects force (mass or torque).
Load cells are also known as load transducers because they convert a load (force) into electrical signals.
 Ultrasonic Sensor – is an electronic device that emits an acoustic wave beyond the upper range of human hearing called the audible range ( 20 hertzto 20 kilohertz), and determines the distance between the sensor and an object based on the time it takes to send the signal and receive the echo.

1.12 PROJECT ORGANISATION
The work is organized as follows: chapter one discuses the introductory part of the work, chapter two presents the background literature review of the work, chapter three describes the methods applied, chapter four discusses the results and system test, chapter five summarizes the research outcomes and the recommendations.