Group #5
Samuel Rodriguez
Daniel Thompson
Chadrick Williams
Giselle Borrero
Sponsored by:
Dept. of Veterans Affairs
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Wireless monitoring pulse oximeter, blood
oxygen concentration (SpO2) and fall detection
Consists of four units
◦ Receiving Display unit (RDU)
◦ 3 Transmitting Sensor Units (TSU)
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All units will be worn by the patient
Finger sensor will obtain pulse and SpO2 and
transmit
Chest and thigh sensor will determine patients
posture information
Waist display will receive data, display data, and
transmit emergency signals
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Ultimately to monitor patients for chronic
heart and related health conditions
Remotely contact emergency services
Provide location to emergency services of
patient
More affordable than existing wireless units
Ideal for a variety of users
Maximum protection at minimal to no cost
Transmitting Sensor Units (TSU)
 To be worn on the finger, wrist, chest and right thigh
 Battery powered
 Control the pulse oximeter sensor
 Make calculations to achieve pulse and oxygen concentration data
 Determine the posture of the patient
 Measure patient’s angular velocity and acceleration
 Monitor unit’s battery life
 Transmit data wirelessly to the waist unit (RDU)
Receiving Display Unit (RDU)
 Receive data wirelessly from TSUs
 Display patient’s pulse and oxygen concentration
 Contact emergency services
 Monitor unit’s battery life
 Audible and visual alerts for critical conditions, loss of signal and battery
life, and display personal information
Chest Unit
Waist Unit
Thigh Unit
Hand Unit
• Non-invasive optical measurement of heart rate
and blood oxygen saturation
• Hemoglobin is the red colored substance in
blood and is the carrier of oxygen
• Red and infrared light are attenuated less by the
body tissues and more by blood (600nm,
940nm)
• Light shines through finger and strikes a
photodiode, which creates a very small current
based on the amount of light incident on the
photodiode
• This determine attenuation of light based on the
output of the photodiode
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Sensor
◦ Generate alternating pulses of light at 600nm (red) and
940nm (infrared)
◦ Photodiode must detect light in the range of 600nm to
940nm
◦ Convert photodiode current to voltages values between
0V to 2.3V
◦ Accuracy of ±2% (70% - 100%)
◦ ±2 BPM for pulse
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Transmit a maximum of 10 ft
MCU
◦ Two DACs 12-bits
◦ Three ADCs 12-bits
◦ 12 GPIOs
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To calculate pulse oximetry the photodiode current must
be converted to a voltage
This voltage has both a DC and AC component that
represents attenuation of light
DC-constant volume of blood used for auto gain control
AC – ebbing and flowing of blood used for measurements
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Control alternating
pulses by pair of LED
select lines (STG3155)
Common power lines
DAC controls current
through system to avoid
damage to LEDs
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MCU determines DAC output based on DC component input
Utilizes constant DC equation because the DC component from
the red and infrared LEDs must be the same
AGC constantly monitors output from diode and adjusts to
maintain the same voltage
Co is the concentration of oxyhemoglobin (Hb02)
Cr is the concentration of reduced hemoglobin (Hb)
𝛼𝑜𝑛 is the absorption coefficient of Hb02 at wavelength 𝜆𝑛
𝛼𝑟𝑛 is the absorption coefficient of Hb at wavelength 𝜆𝑛
𝜆1 : 𝐼1 = 𝐼𝑖𝑛1 𝑥10−
𝜆2 : 𝐼2 = 𝐼𝑖𝑛2
∝𝑜1 𝐶𝑜 +∝𝑟1 𝐶𝑟 𝑙
𝑥10− ∝𝑜2𝐶𝑜+∝𝑟2𝐶𝑟 𝑙
𝐼
𝑅=
𝑙𝑜𝑔 𝐼 1
𝑖𝑛1 𝜆1
𝐼
𝑙𝑜𝑔 𝐼 2
𝑖𝑛2 𝜆2
𝑙𝑜𝑔 𝐼𝐴𝐶 𝜆1
𝐼𝐴𝐶 𝜆2
𝑅′ = 𝑙𝑜𝑔
𝐶𝑜
∝𝑟2 𝑅−∝𝑟1
𝑆𝑝𝑂2 =
=
𝐶𝑜 + 𝐶𝑟
∝𝑟2 −∝𝑜2 𝑅 − ∝𝑟1 −∝𝑜1
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Determine the patient’s position (sitting,
standing or laying down)
Measure angular velocity and acceleration of
patient
Have a range of ±6g acceleration.
Have an accuracy of angular velocity between
±300˚/s to ±500˚/s
Have a sampling rate of at least 120Hz
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Consist of:
◦ Two 3-axis gyroscopes (ITG-3200)
◦ Two 3-axis accelerometers
(MMA7631L)
◦ One of each in the center of the
chest and right thigh
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MCU MSP430FG438
◦ Three 12-bit ADCs
◦ 34 GPIOs
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RF Transceiver CC1101
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RF transponder receives information from
peripheral units
Multicontroller stores past data and makes
decisions about patient status
16x2 LCD displays patient information,
alerts, emergencies, or system status
Buzzer and LEDs provide visual and
auditory stimulus for alerts
Part number
Number of I/O pins
JN5148
Component size
(mm2)
8x8
CC430
9x9
32 - 64
MSP430F233
12 X12
48
MSP430F2616
12 x 12 or
14 x14
14 x 14
48 or 64
MSP430FG437
21
48
Extra built-in
features
2.4GHz transceiver,
12-bit ADC, 12bitDAC, 4 wire audio
interface
Sub 1GHz
transceiver, 12-bit
ADC, CC1101
12-bit ADC
12-bit ADC, 12-bit
DAC, DMA controller
12-bit ADC, 2x 12-bit
DAC,3x Op Amps,
Analog comparator,
DMA, SVS, LCD
driver
Cost
($)
20
5.00*
2.50*
5.85*
5.15*
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Separate unit from the MCU
Built-in display controller
May display pulse, blood oxygen content,
patient’s name, or alarm information
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Green LED- Blinks if a fall is detected
Blue LED- Blinks if RDU loses signal from
peripherals
Red LED- Blinks if emergency is active or user
has indicated panic
Piezoelectric Buzzer- Pulses if emergency is
active
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All units powered by a battery, through a
DC/DC buck converter
3.3V supply to MCU, RF transceiver, and all
sensor units
5V supply to LCD
Battery voltage monitored by built-in
comparator in the MSP430FG43x
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3.3V output supplies MCU and sensors, directed through
another buck converter to upgrade to 5V for the LCD
anode
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Analog comparator
internal to MCU
Output to Red-YellowGreen LED
Voltage divider from
battery, scaled with the
MCU’s maximum output
voltage
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Language: C
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Testing: DevC++ V 4.9.9.2
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Implementation: Code Composer Studio
V4.2.1.00004
Wireless: SimpliciTI
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Schematics: Cadsoft EAGLE V 5.11.0
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MSP-FET430UIF
EM430F6137RF900
Accurate, Fast Fall Detection Using
Gyroscopes and AccelerometerDerived Posture Information
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The linear acceleration
and rotational rate of
the chest and thigh for:
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Standing
Walking
Sitting
Running
Cc1101: 4mm x 4mm
CC1101 Evaluation
Module 433MHz
Example
SimpliciTI Structure
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Finish and order PCB design
Transferring code on boards
Bluetooth interfacing
Coding for the oximeter
Interfacing system clocks
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Lots and lots of testing!
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Done
Left
Research
90%
Design
85%
Parts Acquisition
75%
Software
Testing
Overall
70%
10%
60%
Original budget
Current spending
Subsystem
Subsystem
Waist
$77.20
Waist
$90.72
Chest
$75.98
Chest
$70.98
Hand
$36.50
Hand
$54.39
Thigh
$75.98
Thigh
$70.98
Design
$438.24
Design
$199.00
Total
$703.89
Total
$486.07