Sensor Report: Part I

Body Fat monitor

Why do we need to know body fat?
Everybody cares about his own health condition, to see if he or she is in a good shape. Weigh is an easy-getting information that shows you if you're out of shape. However, counting on weight only is too risky because it doesn't show you how much fat you have which is the main factor causing heart disease. Too much fat, obesity, is definitely neither good looking nor healthy.

Nowadays we have mainly two ways (regardless of those non-mainstream ways)to know how much body fat one has. First, the luxury way, is to go to some hospitals or health centers, spending a lot of money to let those professional immerse you in a water tank and measure very detail displacement of your body fat. The other way is to buy a cheap body fat monitor from stores and measure your self anytime you want to.


Theory
Body fat monitor often uses a technology called "Bioelectrical Impedance Analysis"(BIA) which measures the impedance to an electrical signal in your body which might be seen as the level of obesity. Actually it shots an non-harmful electron into one side or your body(e.g. your left foot) and receive it from the other side(e.g. your right foot). It measures how much the loss of electron is between the start point and the end, and then translate this number of loss into degree or percentage of body fat degree and show it on the screen.

For men, your age & body fat percentage diagram:


The theory of electron loss is a hypothesis that while electron travels through the water found in muscle and fat, the more muscle a person has, the more water their body can hold. The greater the amount of water in a person's body, the easier it is for the current to pass through it. In contrast, the more fat, the more resistance to the current. The factors that go into determining the percentage of body fat include a person's weight, height, age, gender and body type.

For women, your age & body fat percentage diagram:



How to use a body fat monitor:
Before using the scale for the first time you enter your age, gender, height. Weight is displayed on the LCD screen and five seconds later your percentage of body fat appears. Usually you will get higher body fat value in the morning than evening because after a sleep the food you consumed at daytime already transform into body fat.


Typical Body Fat Monitor

The one I have in hand is made by Tanita, the company who claims to be the world leader in precision electronic scales. Tanita's device looks like a normal bathroom scale, using 4 normal AA batteries as power supply.









Specification:

To be written...

Parts

Outlook

Switch

Screen

Input Buttons

Pads(shot and receive electron)


To be written...

Diagram
To be written...