Abstract—This paper is about the development of non-invasive heart rate and oxygen saturation in human blood using Altera NIOS II soft-core processor system. In today's world, monitoring oxygen saturation and heart rate is very important in hospitals to keep track of low oxygen levels in blood. We have designed an Embedded System On Peripheral Chip (SOPC) reconfigurable system by interfacing two LED’s of different wavelengths (660 nm/940 nm) with a single photo-detector to measure the absorptions of hemoglobin species at different wavelengths. The implementation of the interface with Finger Probe and Liquid Crystal Display (LCD) was carried out using NIOS II soft-core system running on Altera NANO DE0 board having target as Cyclone IVE. This designed system is used to monitor oxygen saturation in blood and heart rate for different test subjects. The designed NIOS II processor based non-invasive heart rate and oxygen saturation was verified with another Operon Pulse oximeter for 50 measurements on 10 different subjects. It was found that the readings taken were very close to the Operon Pulse oximeter. Keywords—Heart rate, NIOS II, Oxygen Saturation, photoplethysmography, soft-core, SOPC. I. INTRODUCTION NE of the most important elements needed to sustain life is oxygen (O 2 ) because it is used by cells to turn sugars into usable energy. Oxy-hemoglobin (HbO 2 ) is found in red blood cells which is bonded to O 2 that delivers 98% of oxygen to the cells. The measurement and calculation of oxy- hemoglobin (HbO 2 ) in arterial blood is known as Oxygen Saturation (SpO 2 ) [1], [2]. Originally, SpO 2 was measured invasively by Arterial Blood Gas (ABG) sampling. In this technique, the blood sample is drawn from an artery and analyzed each time, the arterial blood gas provides only intermittent monitoring which may not be ideal for monitoring unstable patients. Since this technique is invasive, it is inconvenient, painful and can cause infections like arterial thrombosis and gangrene. The need for a non-invasive method of measuring SpO 2 in real-time led to the development of a device to measure heart rate and oxygen saturation [2]. A healthy person should have SpO 2 in between 94% to 100%. The photoplethysmography (PPG) is obtained by measuring changes in light intensity absorbed by the blood for different wavelengths. Red and near infrared wavelengths are Caje F. Pinto is with the Department of Electronics, St. Xavier's College, Mapusa, Goa, India (Corresponding author, phone: +919823054798; e-mail: caj786@gmail.com). Jivan S. Parab and Gourish M. Naik are with the Department of Electronics, Goa University, Taleigao, Goa, India (e-mail: jsparab@unigoa.ac.in, gmnaik@unigoa.ac.in). used because these can easily penetrate through tissues [3]. From PPG signal, oxygen saturation is derived from the ratio of the absorption of the two wavelengths [4]. It is important to monitor oxygen level in blood when the patient is in the recovery room and intensive care unit to detect hypoxemia. Also, it can be used to monitor oxygen level of a person while exercising and for normal outdoor activities. A heart rate meter is a device that allows a person to measure and monitor their heart beat in real time. The heart rate of a healthy grown-up at rest is around 72 beats per minute (bpm) and infants is around 120 bpm, while more older kids have heart rates around 90 bpm. The heart rate rises progressively during activities and returns gradually to the rest after exercise. The rate when the beat comes back to normal value means that the individual is fit [5], [9]. If the heart rate is lower than normal value, it is known as bradycardia, if the heart rate is higher than normal value, it is known as tachycardia. Normally Heart rate is measured by placing the thumb over the person's arterial pulsation and counting the number pulses in a 60 second period [5], [9]. Heart rate measurement is very important because it indicates the efficient functioning of cardiovascular system. The important physical property is that the blood color changes depending on oxygen saturation and hemoglobin absorbs different amounts of light. Deoxy-hemoglobin absorbs more red light than oxy-hemoglobin. As oxygen saturation falls, the blood becomes darker and more red light is absorbed. At near infrared range of light, oxy-hemoglobin absorbs more infrared light than deoxy-hemoglobin [2], [4]. II. RELATED WORK SpO 2 Sensor in a wearable Monitor was constructed using LED's/Photodiode with a signal conditioner along with Arduino Uno in [2] to measure and display oxygen saturation on the Smart Phone using Android application. Heart Rate Counter was designed using PIC16F628A along with LED's/ Phototransistor with a signal conditioner in [5] to measure heart rate in relaxed state and stressed state. Reference [6] showed that Pulse Oximeter was done using Arduino Uno, LED’s/detectors to calculate heart rate and oxygen saturation. Also, pressure sensor probe was used to measure blood pressure. Continuous monitoring of Pulse Rate and Oxygen saturation with LabVIEW was done by using LED driver circuit, transimpedance amplifier in [7]. The signals from the SpO 2 sensor probe were fed to the amplifying circuit which was interfaced using the interfacing software ‘LabVIEW’ through Data Acquisition card (DAQ card) and the results were displayed in the LabVIEW front panel. Reference [8] Caje F. Pinto, Jivan S. Parab, Gourish M. Naik Development of Soft-Core System for Heart Rate and Oxygen Saturation O World Academy of Science, Engineering and Technology International Journal of Bioengineering and Life Sciences Vol:12, No:2, 2018 35 International Scholarly and Scientific Research & Innovation 12(2) 2018 scholar.waset.org/1307-6892/10008538 International Science Index, Bioengineering and Life Sciences Vol:12, No:2, 2018 waset.org/Publication/10008538