WEEK3

2. Heart Rate Detector

(1). Use the simple filter, the result can be observed, but with many noises.

(2) So, we build the second order filter combinated with low pass filter and high pass filter.

LOW-PASS FILTER

HIGH-PASS FILTER

Demonstration

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WEEK 2

Part 1 - Pedometer The whole algorithm was shown below. Part 2 - Heart Rate Sensor 1.Use simple band-pass filter (1-3Hz) to reduce the affect of the noise. f1=1/(2*pi*R1*C1)=1Hz f2=1/(2*pi*R2*C2)=3Hz where C1=1uF R1=560K C2=5.3uF R2=10K The band-pass filter with a pass-band from 1 Hz to 3 Hz to allow the heart beat signal to come through and the rest of the signal noise to be rejected. 2. Use amplifier to amplify the signal we expected. Gain = 1 + (R2/R1) Gate= 1+1M/10K=101 The oscilloscope was used to measure the voltage drop on the photoresistor. As expect, the voltage will change because the red light through the figure will change with the oxygen content of blood. The expected result is a pulse wave similar to human heartbeat, but the amplitude was about 3mV measured by multimeter. H...

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WEEK 1

WEEK 1 This smart sports watch has two main functions. First, it can detect the user's heart rate. When users are exercising, paying attention to their heart rate can better protect and regulate themselves. Next, it can detect the user's steps. For sedentary people, it plays a role in urging themselves to exercise. Heart Rate Measurement The aim is to build a heart rate measurement using the LED and photoresistor without a pulse sensor to measure the heart rate on the finger. The materials we intend to use are photoresistor with maximum sensitivity about 650nm and Red LED with 10000mcd brightness. The principle we refer to is as follows. A heart rate is formed by two parts, the systole and the diastole. One heart rate will be measured after a systole and diastole is finished. The systole is the process that the blood is pushed to the body from the heart, conversely, the diastole occurs as blood flows back to the heart from the body. This project measures hea...