Team Pacemaker
Apparatus for the Analysis of Heart Sounds
Electronic Stethoscope / EKG Device
Luke Philips
Ryan Laterza
Min Dong Bian
Sarah Makhija
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
Design Summary
Medical Doctor
SoundStethoscope
Electrocardiogram Action Potential1
1
Reads
11 Amplfies1
1
Listens
11 Records 1* Conducts
11 Emit
Heart
Valve
Cardiac Muscle
4
1 Has
1
1 Has
11 Treats
Current Domain Model
Design Summary (cont.)
Medical Doctor
Sound
Hardware Device
SD Card
Action Potential
11
Reads 1
1
Records
1
1
Writes
1
1
Records 1* Conducts
11 Emit
Heart
Valve
Cardiac Muscle
4
1 Has
1
1 Has
1
1 Treats
Software Utility
1
1
Generates
Three Dimensional Plot
1
1
Analyzes
Future Domain Model
Project Diagram
Preliminary Graphical Displays
•Dr. Weinberger’s data files•No accompanied EKG data
EKG Triggering & Averaging
10 sec. FFT of Filtered Stethoscope
Data
Mixed Signal Microcontroller TI MSP430F1611
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
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
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;
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);}
}}
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
2. Single-Supply CMOS Operational Amplifiers
OR…
Simple Circuit Testing for Optimal Design
OPA 335 LF356
3. Bypass Capacitors
0.1 nF & 4.7 nF
Before & After Adding Amplifier
EKG Schematic
Title
Size Document Number Rev
Date: Sheet of
<Doc> <RevCode>
EKG schematic
A
1 1Wednesday, March 01, 2006
Differential Amplifier INA321
Right Electrode
Left Electrode
DAC1
<Value>
3
1516
11
1
14
-
+
U2A
EL2360C-N
3
1312
11
5
14
-
+
U2BEL2360C-N
R1
100K
R2
100K
R3
RESISTOR
R4
RESISTOR
R5
1M
R6
1M
R7
10K
R81M
R9800
R10
RESISTOR
R11
RESISTOR
R122.2M
R132.2M
C1
01nF
C2
4.7nF
Power & User Interface
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
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)
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
UI
LCD, two stages:– Hantronix HDM08216L
• 8x2
– Seiko Backlight Graphic LCD
UI
• Keypad • 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
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