IJRET: International Journal of Research in Engineering and Technology eISSN: 2319-1163 | pISSN: 2321-7308 _______________________________________________________________________________________ Volume: 04 Issue: 06 | June-2015, Available @ http://www.ijret.org 437 DESIGN AND DEVELOPMENT OF REAL TIME RESPIRATORY RATE MONITOR USING NON-INVASIVE BIOSENSOR Karthik Mohan Rao 1 , B.G. Sudarshan 2 1 PG Student, Department of Instrumentation Technology, RV College Of Engineering, Bengaluru, India 2 Associate Professor, Department of Instrumentation Technology, RV College Of Engineering, Bengaluru, India Abstract Respiration Rate is one of the vital signs which require regular monitoring among diseased people. There are a number of medical devices developed to monitor human health condition among them RR monitor is one. The Respiration rate monitor is a device that measures the subject’s respiration rate non-invasively. The objective of the proposed work is to design and develop a low cost Respiration rate monitor for clinical applications. The main parameter to be used is the temperature of respired air i.e. both inspired and expired air. Hence this device uses Thermistor as the source sensor which will provide the temperature feedback of the inspired and expired air. The proposed work uses the ATMEL AT89S52 microprocessor with external ADC0809. The magnitude voltage during the inhalation and exhalation is converted into digital signal using ADC. The further process involves a peak detection technique. The number of peaks obtained in duration of one minute gives the Respiration Rate. The so obtained Respiration Rate is sent to the concerned physician’s cell phone through GSM modem. The device gives an alarm and sends request via SMS if there is tachyopnea and bradyapnea. Keywords: Respiratory Rate, Peak Detection, ADC, GSM, SM, Threshold. ---------------------------------------------------------------------***--------------------------------------------------------------------- 1. INTRODUCTION Biomedical Engineering is an interdisciplinary field that utilizes concepts and principles of many engineering domains to postulate concepts and techniques useful in designing and building a variety of healthcare products. There are numerous biomedical devices that are in current use, all aimed at improving human health and welfare [1]. Respiration Rate Monitor is one of the biomedical devices that will monitor the subject’s breath rate. The respiratory rate (RR) is the number of breaths taken within a set amount of time (typically 60 seconds) [2]. Normal respiration rates for an adult person at rest range from 12 to 16 breaths per minute. A normal respiratory rate is termed as eupnea, an increased respiratory rate is termed as tachypnea and a lower than the normal respiratory rate is termed as bradypnea [2]. Vital signs are estimations of the body's most fundamental capacities [3]. There are four vital signs that are used for monitoring the patients. They are pulse rate, blood pressure and body temperature, respiratory rate. The respiratory rate is one of the four vital signs (the others being pulse rate, blood pressure and body temperature) that are considered standard for monitoring patients on acute hospital wards. Unusual respiratory rates in the subject judge the serious clinical actions like Cardiac arrest. If the respiratory rate goes high above 27 respirations per minute then it is the mainly important analyst of cardiac arrest [3]. During the respiration there will be a change in respired air temperature, moisture, chemical composition of the air, and in its volume. The breathed out air is hotter than the air that is breathed in by around 2-3°C much of the time. The breathed in air is at the room temperature which is normally around 25°C (70°F), and the breathed out air has a temperature of around 28°C (82.4°F). If the inspired air is warmer, then the heat lost from the body during the respiration process is lesser [3]. Breathed in air contains dihydrogen monoxide vapor, yet is rarely immersed. The breathed out air is proximately immersed for the temperature at which it leaves the body. In this way, the breathed out air picks up dihydrogen monoxide vapor and carts it away from the lungs [3]. Breathing builds up a transmutation in the chemical composition of the air. Breathed in air embodies around 20.947% of Oxygen (O 2 ) and 0.033% of Carbon Dioxide (CO 2 ) by volume, though the breathed out air contains 15.4% of Oxygen (O 2 ) and 4.3% of Carbon Dioxide (CO 2 ) by volume. Breathed out air withal contains unstable natural substances in immensely minute amounts [3]. Breathed out air is more massive than breathed in air since it has water vapor added to it, as well as is extended in outcome of its high temperature. In the event that, notwithstanding, it is dried and decreased to the same temperature as the breathed in air, its volume will be found to reduce, since it has lost 5.4 volumes of oxygen for each 43 volumes of carbon dioxide which it has picked up[3]. Many types of respiratory rate monitors have been used for the measurement of the Respiration Rate. Respiration Rate monitor using Ultrasonic Sensor and Respiration Rate monitor using facial tracking method is the non-contact