Transcript presentation

Pulse Rate Monitor
Ying Wang
Department of Electrical and Computer Engineering
University of Illinois at Urbana-Champaign
Outlines
• Project Objective
• Modules and Design Review
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•
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Power Module
Sensor Module
Microcontroller Module
Display Module
• Requirements and Verifications
• Test Results
• Outlook
Objective
• This project intends to realize a device that can read the human pulse
rate from a fingertip. The pulse rate in the unit of beats per minute
(BPM) will be displayed by a 16 by 2 LCD display.
BLOCK DIAGRAM
Power Module
• 5 V REGULATOR CIRCUIT
0.6 V
5.6 V
Sensor Module: IR Emitter and Detector
Output of IR detector (Raw Data)
5V
Measured by Processing
0V
0s
1s
2s
3s
4s
5s
Sensor Module: Filter
From detector
output
Sensor Module: Amplifier
C3
U2
output of f ilter
5V
+
OUT
go to Arduino A0
R51
-
OPAMP
R6
R52
R53
Gain= (R6+R7)/R7
R71
R72
Sensor Module Output
5V
Measured by Processing
0V
0s
1s
2s
3s
4s
5s
Microcontroller: Arduino Uno
Find a peak
Data[i] > Data[i-1] &&
Data[i] > Data[i+1];
Currentpeak = Data[i];
Currentime = millis();
Refpeak = Currentpeak;
Reftime= Currenttime;
Find a newpeak;
Currentpeak = newpeak;
Currenttime = millis();
YES
CurrentpeakRefpeak >
PeakTol
NO
NO
|currentpeak-Refpeak|<
PeakTol && |ReftimeCurrenttime|> timeTol
YES
Pulserate = 60000/ (currenttime Reftime)
Requirements and Verifications
Requirement
Verification
1. Power Supply
take a 9V battery input and output a stable 5V(+/-0.4V) voltage to the
rest of circuit and within +/-0.2A of needed current.
Put a voltmeter across the output of regulator circuit, the voltage
should be within 5V+-0.4V. The components of the circuit should all
work properly without any short or overload.
2. Pulse Sensor
The pulse sensor should output an accurate periodic analog signal to
microcontroller. The periodic wave should correspond to the pulse of
the testing people within 5 beats per minute.
The output of the pulse sensor circuit could be verified by using a free
software called “Processing” It could sketch the output of the pulse
sensor circuit synchronously to a PC screen. Then we can count the
pulse per minute based on the waveform (the window duration time of
“Processing” is set to 5 seconds) and compare it with the result of
iPhone App “Heart Rate”
3. Microcontroller
The Microcontroller takes the output of the Pulse Sensor and correctly
calculate the beats per Module minute and output to the display
module. The beats per minute should be accurate within 5 beats/min
The calculated beats per minute can be displayed by 16 y 2 LCD display
then we can compare the output of the microcontroller with the
waveform generated by pulse module and results from iPhone App
“Heart Rate”. The testing people can put one hand on pulse sensor and
the other hand on iPhone.
4. Display Module
To be compared with the beats per minute value displayed by iPhone
Takes the output of the microcontroller and convert it to sixteen by two App “Heart Rate” by putting one hand on pulse sensor and the other
LCD display. Display beats per minute on LCD screen
hand on iPhone.
Test Results
• All modules worked
Test Results
• Some problems:
• Fingers have to maintain a stable pressure, if peak height varies too much, a
peak might be missed
• PCB board didn’t work, might have some soldering problem
More can be done…
• Study the heart rate variation
• Calculate the target heart rate (THR zone is 50%-85% of maximum
heart rate)