Team Pacemaker
Luke Philips
Ryan Laterza
Min Dong Bian
Sarah Makhija
Apparatus for the Analysis of Heart Sounds
Electronic Stethoscope / EKG Device
March 2, 2006
CDR – Apparatus for the Analysis
of Heart Sounds
Project Objectives
• Provide objective means of analyzing
cardiac acoustics
– Aid in diagnosis of heart murmurs
• Amplified signal from stethoscope, EKG
– Synchronized signals
• Handheld device, portable memory,
graphical display
March 2, 2006
CDR – Apparatus for the Analysis
of Heart Sounds
Design Summary
Reads 1
Electrocardiogram
1 Records 1
*
Action Potential
Conducts 1
1
Cardiac Muscle
Has
1
1
1
Medical Doctor
1
Stethoscope
Listens
1
Treats
1 Amplfies 1
Sound
1
Emit
1
1
Valve
Has
4
Current Domain Model
March 2, 2006
Heart
CDR – Apparatus for the Analysis
of Heart Sounds
1
Design Summary (cont.)
1
Analyzes
Three Dimensional Plot
Medical Doctor
1
Treats
1
Generates 1
Records
1
1
*
Action Potential
Conducts 1
Cardiac Muscle
1
Has
1
1
Software Utility
Writes 1
Hardware Device
Heart
1
1
1
Reads
1
SD Card
1
Sound
Records
1
Emit
1
1
Future Domain Model
March 2, 2006
CDR – Apparatus for the Analysis
of Heart Sounds
Valve
Has
4
1
Project Diagram
Lithium Ion
Battery –
860 mAH
Electrocardiogr
am (ECG)
Signal
Differential
Amplifier
Low Pass
Filter
Fc = 5 kHz
12-bit
ADC
15 ksps
Heart
Contraction
Sound
Differential
Amplifier
Low Pass
Filter
Fc = 42 kHz
12-bit
ADC
100
ksps
Alphanumeric
Keypad - 4x3
March 2, 2006
Plots
Electrocardiogram
(ECG) and Acoustic
Frequency Spectrum
SPI Bus
Secure Digital
Card - 512 MB
General
Purpose
I/O
Liquid Cristal
Display - 16x2
Character
MCU
MSP430F1611
General
Purpose
I/O
Input Color
Output Color
CDR – Apparatus for the Analysis
of Heart Sounds
Software Utility
– Fast Fourier
Transform
Preliminary Graphical Displays
•Dr. Weinberger’s data files
•No accompanied EKG data
March 2, 2006
CDR – Apparatus for the Analysis
of Heart Sounds
EKG Triggering &
Averaging
10 sec. FFT of
Filtered Stethoscope
Data
March 2, 2006
CDR – Apparatus for the Analysis
of Heart Sounds
Mixed Signal Microcontroller
TI MSP430F1611
March 2, 2006
CDR – Apparatus for the Analysis
of Heart Sounds
MSP430F1611 Features
•
•
•
•
•
Program Memory Type Flash
Program Memory 48 kB
RAM 10 kB
I/O Pins 48
ADC 12-bit SAR
– 8 Software Programmable Input Channels
– 200 ksps Maximum Conversion Rate
• Integrated Peripherals DMA, 2 12-bit DAC
• Interface 2 Hardware SPI or UART
• Pin/Package 64LQFP
March 2, 2006
CDR – Apparatus for the Analysis
of Heart Sounds
Programming the Microcontroller
• MSPGCC
– Free C Compiler TI MSP430 Family
– Windows and Unix Compatible
– Supports the MSP430F1611 MCU
– Supports JTAG Interfacing
• Interface Used to Download Code from the PC to
the MCU via a Serial/Parallel/USB Adapter
March 2, 2006
CDR – Apparatus for the Analysis
of Heart Sounds
Example C Code
“Blinking Lights”
#include "hardware.h"
void delay(unsigned int d) {
int i;
for (i = 0; i<d; i++) {
nop();
nop();
}
}
int main(void) {
int i;
int o = 0;
WDTCTL = WDTCTL_INIT;
P1OUT = P1OUT_INIT;
P2OUT = P2OUT_INIT;
P1SEL = P1SEL_INIT;
March 2, 2006
P2SEL = P2SEL_INIT;
P1DIR = P1DIR_INIT;
P2DIR = P2DIR_INIT;
P1IES = P1IES_INIT;
P2IES = P2IES_INIT;
P1IE = P1IE_INIT;
P2IE = P2IE_INIT;
while (1) {
//main loop, never ends..
for (i=0; i<8; i++, o++) {
P1OUT = (1<<i) |
(0x80>>(o&7));
delay(0x4fff);
}
}
}
CDR – Apparatus for the Analysis
of Heart Sounds
EKG
Amplifier Circuit Design
March 2, 2006
CDR – Apparatus for the Analysis
of Heart Sounds
Amplifier Implementation
1. LF155/LF156…./LF356 JFET input
Operational Amplifiers
Applications:
•Precision High Speed
Integrators
•Fast D/A & A/D Converters
•High Impedance Buffers
•Wideband, low noise, low
drift amplifiers
March 2, 2006
CDR – Apparatus for the Analysis
of Heart Sounds
Advantages
March 2, 2006
CDR – Apparatus for the Analysis
of Heart Sounds
OR…
2. Single-Supply CMOS Operational
Amplifiers
March 2, 2006
CDR – Apparatus for the Analysis
of Heart Sounds
Features
March 2, 2006
CDR – Apparatus for the Analysis
of Heart Sounds
Applications
March 2, 2006
CDR – Apparatus for the Analysis
of Heart Sounds
Simple Circuit Testing for Optimal
Design
OPA 335
LF356
3. Bypass Capacitors
0.1 nF & 4.7 nF
March 2, 2006
CDR – Apparatus for the Analysis
of Heart Sounds
Before & After Adding Amplifier
March 2, 2006
CDR – Apparatus for the Analysis
of Heart Sounds
EKG Schematic
C2
4.7n F
R1 0
R5
RE SIS TOR
1M
R1
R3
Di ffe re nti al A mpl ifi er INA 321
R7
1
RE SIS TOR
C1
R6
01 nF
1M
16
10 K
+
15
-
3
10 0K
U2 A
11
14
Le ft El ectrod e
Ri gh t El ectro de R2
14
11
EL 236 0C-N
R4
R1 1
13
10 0K
+
-
RE SIS TOR
R9
80 0
U2 B
EL 236 0C-N
5
R8
1M
12
3
RE SIS TOR
R1 3
2.2M
R1 2
2.2M
DA C1
Ti tle
EK G sch ema ti c
<V al ue>
Si ze
A
Da te :
March 2, 2006
Do cum ent Numb er
<Doc>
Wed ne sd ay, March 0 1, 200 6
CDR – Apparatus for the Analysis
of Heart Sounds
Re v
<RevCod e>
Sh eet
1
of
1
Power & User Interface
March 2, 2006
CDR – Apparatus for the Analysis
of Heart Sounds
Power
• Power Supply
– “wall wart” interface
• Supplies up to
9VDC/300mA
– Regulated 5V/3.3V
– Stand alone Battery
Charger
• AC12050615A-01
single cell charger
– Numerous
Adjustable Voltage
Regulators
March 2, 2006
CDR – Apparatus for the Analysis
of Heart Sounds
Power
• Battery
– ED053455-2C
• 860mAh Polymer
Lithium Ion Battery
• High Energy Density
• Low Cost
• 3.7V Nominal Working
Voltage
• Low Weight - 0.65oz
(18.5g)
• Excellent Temperature
Performance
• Self-Discharge: <8%
(per month)
March 2, 2006
CDR – Apparatus for the Analysis
of Heart Sounds
Power
• Intelligence
– TI-TPS65011
• Multi-Channel 1-cell
Li-Ion Power Mgmt
IC
• 2DC/DC, 2 LDOs,
I2C interface
TPS65011
Regulated Outputs(#)
4
Vin(Min/Max)(V)
2.5/6
Vout(Min/Max)(V)
2.5/3.3
Vout2 Adj(Min/Max)(V) 0.85/1.8
Iout3(A)
0.2
Iout4(A)
0.2
Vout3 Adj(Min/Max)(V)
0.9/6
Vout4 Adj(Min/Max)(V)
1.8/3
March 2, 2006
CDR – Apparatus for the Analysis
of Heart Sounds
UI
LCD, two stages:
– Hantronix HDM08216L
– Seiko Backlight Graphic LCD
• 8x2
March 2, 2006
CDR – Apparatus for the Analysis
of Heart Sounds
UI
• Keypad
March 2, 2006
• Low power Keypad
Interface With the
MSP430
• interrupt driven
• Low power if all keys are
pressed and held
simultaneously
• No crystal required
• Minimal external
components
• Suitable for MSP430
CDR – Apparatus for the Analysis
of Heart Sounds
Updated Schedule & Division of
Labor
Milestone 1 – Data sampling; Power device; EKG Circuit
Milestone 2 – UI / Software Integration
Expo – Device able to acquire and display data
March 2, 2006
CDR – Apparatus for the Analysis
of Heart Sounds
Thank You!
Questions/Comments?
March 2, 2006
CDR – Apparatus for the Analysis
of Heart Sounds