17-06-2013, 03:56 PM
Walking Stick With Heart Attack Detection
Walking Stick.ppt (Size: 146.5 KB / Downloads: 124)
Introduction
Why did we choose this topic?
Create an equipment to be used in everyday’s life for a medical purpose
Obtain the basic idea from “Wireless Heart Attack Detector with GPS” of Fall 2004
Most heart attack results from coronary artery disease (the restriction of blood flow to the heart) and it causes instant death of person
Objective
Goals of Design:
-The wireless heart attack detector captures abnormal heart beat signals.
-The alert system on the walking stick warns the user to realize his health condition.
-Bluetooth wireless emergency calling system calls for help at the moment of heart attack via mobile phone.
Benefits:
Electrocardiogram (ECG) signal transmitted wirelessly from the wrist to the main unit on the stick. This avoids the inconvenience of the attachment of the stick to the wrists.
Automatic wireless emergency calling system via Bluetooth module
Warning mode giving the users a chance to avoid the fatal moment actively
Original Design Review
Obtain ECG waveform from both wrists.
Transmit ECG waveform wirelessly from wrist to a receiver on the stick.
Microcontroller on the stick will run a heart attack algorithm to detect possible heart attack.
Microcontroller will make the user’s cell phone to call 911 if heart attack detected.
Components and Functions
ECG Analog Circuitry
– to obtain analog ECG waveform from wrists
1. Unity-Gain Buffer.
As Impedance Transformer. Skin impedance is high and Op-Amp’s input impedance is infinity.
2. Differential Amplifier.
Taking the difference between two bio signals from both wrists and output the ECG waveform with desired gain.
Components and Functions
HP-3 Receiver
1. The receiver will receive digital ECG waveform from wrist.
2. The receiver will then feed the digital signal to Javelin microcontroller.
Components and Functions
Amplitude is considered weak if it is below 50% of the baseline.
-Checking Irregular Heart Beat
- normal pulse rate is between 35bpm and 200bpm
- if pulse rate falls outside of this range, then heart attack symptom is detected.
Components and Functions
EB500 Bluetooth Module
-Javelin Stamp will send some commands to EB500 to set up a connection between the bluetooth module and the cell phone.
-Bluetooth communication is nothing than just a wireless serial cable after the connection is set up.
Functional Testing
Heart Attack Algorithm Testing
One of the ECG samples shown was stored and was changed in terms of amplitude, rate and width.
Javelin Stamp was modified to run with this modified data.
Each of the three thresholds responded correspondingly.
Successes & Challenges
Challenges Before Successes
Each component has to be tested and debugged individually before they were combined together.
TTL logic signal of PIC were captured by scope to test the functionality.
- ECG waveforms were captured by Javelin Stamp to test the wireless communication between wrist and the stick.
-Suitable bluetooth module was selected carefully by reading data sheets to check certain commands to make sure that it is connectable to a cell phone.
Test
Operation Temperature
We chose the reasonable range of outer weather.
Test Range: -25°C to 50°C inside freezer and by hair dryer
Result: We could observe that the whole system behaved properly.