International Journal of Computer Applications (0975 – 8887) Volume 47– No.25, June 2012 30 Design of Wireless Anti-spoofing Device for Measuring Blood Oxygen Concentration and Heart Rate Vipin Gupta PEC University of Technology Chandigarh, India Mandeep Singh Engineer, DEC Division C-DAC, Mohali, Punjab India Rita Mahajan PEC University of Technology Chandigarh, India ABSTRACT This project describes to design anti-spoofing device which measures continuously heart rate, blood oxygen concentration and record the data of the patient on PC screen serially. When the data of the patient goes below the critical value, the monitoring system automatically transmits the information to the doctor's hand phone on the mobile network as a SMS via a GSM device. Thus it’s alert to doctor to quickly attend the patient and give diagnosis to the patient's. This project made the device economical and also creates the easy pathway between the patient and doctor which provide better health care facility to patient. Keywords Pulse Rate, SpO 2 , Microcontroller, PC, LM358, ADC, GSM modem 1. INTRODUCTION Pulse-oximeter is a non-invasive device uses two frequencies of light (red and infrared) to determine the percentage (%) of hemoglobin in the blood that is saturated with oxygen. The percentage is called blood oxygen saturation or SpO 2 . It also measures pulse rate at the same time. Pulse-Oximeter is based on measuring the absorption of red and infrared light that passes a patient finger by using light sensors .Absorption on each wavelength differs significantly for the oxygenated hemoglobin and deoxygenated hemoglobin. The oxygenated hemoglobin allows red right to transmit through and absorbs more infra red light while the deoxygenated hemoglobin allows infrared to transmit through and absorbs more red light as shown in Fig.1 Figure 1: The absorption levels of oxygenated and deoxygenated blood at different wavelength [13] The absorption of light by HbO 2 or Hb varies with the pulsatile flow of blood into the tissues, so the absorption varies with the same frequency as the heart beat. With each heart beat, the volume of arterial blood in the tissue increases, while the remaining tissue volume remains constant. This change makes it possible for the oximetry system to differentiate the arterial blood from all other absorbing substance has both DC and AC components in it; this is as shown in Fig 2. Figure 2: AC and DC components of oximetry [14]. The time varying component or the AC part in the absorbance spectrum is due to the arterial injection or fresh oxygenated blood. The steady DC part in the spectrum is caused by the absorbance of light by the tissue, skin and bone. The DC part has no information in determining the oxygen saturation. Only the AC component is the pulsatile waveform which is of our interest. On the basis of the values of AC and DC values of the two frequencies gives the Oxygen saturation. LED’s are used as a light source and sequentially pulsed at a fast rate. To find Oxygen saturation, first calculate R which is absorbance ratio of the arterial blood at the two wavelength is then determined as the ratio of AC variation, each normalize to their DC values.: R= (AC_red÷DC_red) ÷ (AC_IR÷DC_IR) (1) AC_red and AC_IR are the AC components of red and infrared light source .DC_red and DC_IR are the DC component of red and infrared light sources respectively. The formula to find oxygen saturation: SaO 2 = A-B*R (2) While A and B component are two constants, as soon as we get the values of AC and DC component of red and infrared LED. The blood oxygen saturation can be getting very easily by the formula.