Stretch sensor

Before we start the development of Home Apnea Monitor using stretch sensor, there are some study with previous work and present work. Then also do the analysis about the stretch sensor, vibration motor, microcontroller (PIC), and also study about the hardware to known their characteristic, function, and all circuit with related.

1. Stretch sensor 

This is a stretch sensor. As you can see in the picture, when the rubber is stretched, the light becomes brighter. It can also be made to work in reverse, as the rubber stretches the bulb can dim.

Imagine pulling a rubber cord and causing the lights in your room to dim. That is an example of how this material can be applied. Or imagine weaving this onto fabrics to sense if the material is stretching. This sensor allows you to measure how stretched something is,it even works bent around corners.

The material itself is a synthetic rubber. It conducts electricity because of integrated conductive carbon particles. When stretched, the spacing between these particles increases, causing the conductivity to decrease. The decrease in conductivity can be measured or observed visually with some simple electronics, like a light bulb.

Measuring stretch forces isn't easy - unless you have some conductive rubber cord! This cord is 2mm diameter, and 1 meter long, made of carbon-black impregnated rubber. Usually this material is used for EMF gasketing, but it’s also very fun to play with. ^[5]

In a 'relaxed' state, the resistance is about 350 ohms per inch. As you pull on it, the resistance increases (the particles get further apart). As you stretch it out, the resistance increases linearly. So lets say you have a 6" piece - thats about 2.1 Kohms. Stretch it to 10" long and now it is 10"/6"*2.1K = 3.5 Kohms. You can stretch the rubber about 50-70% longer than the resting length, so a 6" piece shouldn't be stretched more than 10". Once the force is released, the rubber will shrink back, although it’s not very 'fast' and it takes a minute or two to revert to its original length. ^[6]

Some ideas for applications:
• Virtual-reality body suits
• Monitor your breathing by wrapping a strap of this material around your chest
• Monitor contractions during childbirth
• Interactive art displays
• Security systems

For this project....

                        Development of Home Apnea Monitor machine is divided into two sections which are on baby belt and main port. For this project, we will use the stretch sensor and vibration sensor while we put them in belt around the chest baby. When the stretch sensor no contraction happened, the signal will send to microcontroller (PIC)  to process and to produce the output such as vibration sensor and alarm or buzzer is on.

Before we start the development of Home Apnea Monitor using stretch sensor, there are some study with previous work and present work. Then also do the analysis about the stretch sensor, vibration sensor, microcontroller (PIC), and also study about the hardware to known their characteristic, function, and all circuit with related.

History

Significant new information has been forthcoming in recent decades on sudden infant death syndrome (SIDS) and apnea during early infancy. This statement focuses on the epidemiologic aspects of SIDS, the lack of a proven association between episodic apnea and SIDS, strategies for prevention of SIDS, and appropriate use of home cardiorespiratory monitoring. Apnea monitors were first introduced in the mid-1960s for the management of apnea of prematurity in hospital settings. Subsequently, cardiorespiratory monitoring has become widely used in the care of infants with a variety of acute and chronic disorders.

The hypothesis that apnea is the pathophysiologic precursor to SIDS was first proposed in 1972. Apnea documented by cardiorespiratory monitoring during prolonged hospitalizations was reported for 2 infants, both of whom were siblings of 3 infants who had died suddenly at home. Both siblings subsequently died unexpectedly after discharge from the hospital. More than 2 decades later, evidence of infanticide for all 5 infants in the original report became known.

The apnea theory never has been proven despite extensive independent research in the several decades after that report. Nevertheless, the home cardiorespiratory monitoring industry, fueled by increasing demand from parents concerned about the risk of SIDS, rapidly developed products aimed at preventing SIDS. Despite the absence of a scientific foundation or evidence of efficacy, home cardiorespiratory monitoring continues to be a common practice in this country.

 It concluded in a 1985 statement that “a causal relationship between prolonged apnea and SIDS has not been established.”  .The recommendations left the use of home cardiorespiratory monitoring in individual situations to physician judgment. The costs of home monitoring are substantial. In 1999, 44% of 26 000 infants weighing 501 to 1500 g at birth and cared for in 325 neonatal units within the Vermont Oxford Network were discharged from the hospital on monitors.16 A conservative estimate of the annual cost of monitoring preterm infants weighing less than 1500 g in the United States is $24 million, and this projection does not include physician fees, repeat pneumograms or sleep studies, other ancillary medical costs, or the costs of other populations of infants who are monitored. In this context, the question of efficacy of home monitoring becomes even more important. Infant death is a tragedy no matter what the cause. This could be due to infant sleep apnea, Sudden Infant Death Syndrome (SIDS), or other pre-existing condition. 

         

Why we uses the apnea monitor..

Introduction

Significant new information has been forthcoming in recent decades on sudden infant death syndrome (SIDS) and apnea during early infancy. This statement focuses on the epidemiologic aspects of SIDS, the lack of a proven association between episodic apnea and SIDS, strategies for prevention of SIDS, and appropriate use of home cardio respiratory monitoring. Apnea monitors were first introduced in the mid-1960s for the management of apnea of prematurity in hospital settings. Subsequently, cardio respiratory monitoring has become widely used in the care of infants with a variety of acute and chronic disorders.

The term of Development of Home Apnea Monitor using stretch sensor is a devices or machine that detects your baby's chest movement (breathing).If your baby's heart rate slows down (bradycardia) or the chest stops moving (apnea), the monitor will produce alarm and vibration motor to alert you to check on your baby. An apnea monitor is not a cure for apnea but to prevent and warn the surrounding people especially for the parents about the sudden infant death syndrome (SIDS). The machine will alarm to let you know when your baby may need help or there are problems with the equipment. When you hear the monitor's alarm you must check on your baby right away for each time. This project is designed using stretch sensor to detect baby chest movement and using (alarm + vibration motor) to more cures about your baby. When the baby breathing the stretch sensor will be contract and relax like the process of breathing we called inhalation and exhalation of diaphragm .When the baby stop breathing (apnea) no contractions happen. If it happen in 15 to 20 second  the sensor will send the signal to produced alarm ,and the same time  the vibration motor will be ON in the Apnea belt of wrapping the around of baby chest. This project not only give alert to parent but also give vibration to baby to get breath. Therefore with this to ensure the parent always looks the baby during sleep. So it can help to reduce the SIDS syndrome.