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Comprehensive Health Monitoring System . Group #5 Samuel Rodriguez Daniel Thompson Chadrick Williams Giselle Borrero. Sponsored by: Dept. of Veterans Affairs. Physical Layout. Chest Unit. Hand Unit. Waist Unit. Thigh Unit. Project Description.
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Comprehensive Health Monitoring System Group #5 Samuel Rodriguez Daniel Thompson Chadrick Williams Giselle Borrero Sponsored by: Dept. of Veterans Affairs
Physical Layout Chest Unit Hand Unit Waist Unit Thigh Unit
Project Description • Wireless monitoring pulse oximeter, blood oxygen concentration (SpO2) and fall detection • Consists of four units • Receiving Display unit (RDU) • 3 Transmitting Sensor Units (TSU) • 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
Goals • 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
Objectives 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
Pulse Oximeter • 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
Pulse Oximeter Design • 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 • Transmit a maximum of 10 ft • MCU • Two DACs 12-bits • Three ADCs 12-bits • 12 GPIOs
Pulse-Ox Sensor • 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
Sensor Control • Control alternating pulses by pair of LED select lines (STG3155) • Common power lines • DAC controls current through system to avoid damage to LEDs
Automatic Gain Control • 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) • is the absorption coefficient of Hb02 at wavelength • is the absorption coefficient of Hb at wavelength
Chest and Thigh Fall Detection Design • 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
Fall Detection Design • 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 • MCU MSP430FG438 • Three 12-bit ADCs • 34 GPIOs • RF TransceiverCC1101
RDU Design • 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
Liquid Crystal Display • Separate unit from the MCU • Built-in display controller • May display pulse, blood oxygen content, patient’s name, or alarm information
Alert Protocol • 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
Power Management • All units powered by a battery, through a DC/DC buck converter • 2.5V supply to Gyroscope logic • 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
Buck DC/DC converter • 3.3V output supplies MCU and sensors, and another buck converter supplies 5V for the LCD anode
Battery Life Monitoring • Analog to digital converter internal to MCU • Output to Red-Yellow-Green LED • Voltage divider from battery, scaled with the MCU’s maximum input voltage
Development Environments Language: C, JAVA Testing: DevC++ V 4.9.9.2 Implementation: Code Composer Studio V4.2.1.00004, eclipse Schematics: Cadsoft EAGLE V 5.11.0
Development Kit MSP-FET430UIF EM430F6137RF900
Fall Detection Algorithm Accurate, Fast Fall Detection Using Gyroscopes and Accelerometer-Derived Posture Information
Fall Detection - Acceleration Sample Output • The linear acceleration and rotational rate of the chest and thigh for: • Standing • Walking • Sitting • Running
Bluetooth • Functions • The uses-permission function is needed in order to use Bluetooth features in any application. This is required to perform different types of communication such as requesting and accepting connections, and transferring data. • The mBluetoothAdapterfunction is needed for any and all Bluetooth activity. It represents the Bluetooth adapter, or Bluetooth radio, and is used for the entire system. • The REQUEST_ENABLE_BT function is to ensure that the Bluetooth is enabled. If the Bluetooth on the device is set off, this function prompts the user to enable Bluetooth through the system settings without stopping the application. <uses-permission android:name=“android.permission.BLUETOOTH”/>; mBluetoothAdapter = BluetoothAdapter.getDefaultAdapter(); startActivityForResult(enableIntent, REQUEST_ENABLE_BT);
Bluetooth • Functions • The startDiscovery() function searches and scans for other dvices. The scanning of devices takes about 12 seconds to complete and scans constantly. • The REQEST_CONNECT_DEVICE function is needed to actually connect to two devices. This is enabled by using the Bluettoth service socket which accepts a connection request and performs the connection. • The callIntent function allows the android application to make a phone call. The number is preset is this function. mBtAdapter.startDiscovery(); startActivityForResult(serverIntent, REQUEST_CONNECT_DEVICE); startActivity(callIntent);
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