ANTSAnesthesiology Neuromuscular

Monitoring System

#25

Group Information

Greg Angelotti (EE)

Otto Cruz (CpE)

Kristin “Zaza” Soriano (CpE/EE)

Sponsor: Dr. Thomas Looke (Anesthesiologist/EE)

Current Methodology

• Administer Neuromuscular Blocking Agents (NMBA)– Blocks Acetylcholine (ACh)

• Trivial neuromuscular stimulating• Subjective muscle response monitoring

(if any at all)• Pen and paper record keeping

Current Methodology

*Courtesy of nursingcrib.com

Current Methodology

Stimulate Monitor Laments

Ulnar Nerve Adductor Pollicis Thumb

Posterior Tibial Nerve Flexor Hallucis Brevis Foot

Facial Nerve Corrugator Supercilli Eyebrow*

Facial Nerve Orbicularis Occuli Eyelid*

* Research shows not as reliable as the first two sites

Objectives

• To safely stimulate targeted sites• To effectively obtain patient signals• To accurately record patient feedback• To create a more organized environment

Requirements

• Must consist of safe modular subsystems• Must obtain objective quantitative

muscular responses• Must produce individual patient feedback

and logging• Must reduce operating room clutter

Overall Block Diagram

SpecificationsShocking Device

Battery 3.7 Volt 2200 mAh Lithium Ion Polymer

Up Time 6 Hours

Idle Time 3 Days

Input Voltage 3.7 Volts

Output Current Variable 0 to 70 mA

Output Pulse Square Wave Pulse 200us Duration

Train of Four Single Set of 4 Pulses Per 2 Seconds

Tetanus 100 Hz (100 Pulses Per Second)

Twitch 1 Pulse Per Second

Dimensions 30 x 40 x 10 mm

Shocking Device

MCU & Bluetooth

Part CC2540 BLE112

Manufacturer Texas Instruments Bluegiga

Dimensions 6.5 x 6.5 x 1 mm

MCU 8051 8051

Memory 128/256 Kb 128/256 Kb

Transceiver Bluetooth 4.0 Bluetooth 4.0

Receiver 19.6 mA 19.6 mA

Transmitter 24.0 mA 27.0 mA

Power Consumption 2 to 3.6 volts 2 to 3.6 volts

Cost (Dev. Kit) $289.75 $350.00

Shocking Device

Shocking Device

Current Control

• PWM to produce the 200us square wave form.

• 10 Bit Serial SPI Dual Output DAC to control current output.

• 2^10 taps (1024) with a 10 bit DAC• Issues deciding between Digital

Potentiometer (voltage) and DAC (voltage & current).

Current Op amp

• Current input varies between 0 to 150 uA.• Current output 0 to 750 mA.• Availability and price is the reason for this

part.

DC to DC Converter

• Optional part• Input 3.1 to 75 volts• Frequency Synchronization

Shocking Device

Negative Feedback

• DC Converter to ADC port on MCU• Digital Integral controller to regulate the

stimulation current.

• Using the formula above will allow us to control the stimulators output.

Shocking Device

Power Supply

• Voltage buck/boost regulator dual output 3.7 volts supplies processor & 5 volts supplies DAC

• Boost Voltage regulator supplies op amp at 8 volts

• The power supply is a 3.7 volt 2200 mAh lithium ion polymer.

Overall Block Diagram

SpecificationsSensor Device

Dimensions 30 x 40 x 10 mm

Battery 5 V

Up Time 6 Hours

Idle Time 3 Days

Data Transmission Bluetooth 4.0

Wireless Range <50 meters

Data Resolution 12 bit

Action Potential Detection 0 - 10 mV

Pressure Detection 0 - 10 lbs

Flex Sensor Angle 0 - 90 degrees

Sensor Device

Surface EMG

• Pick targeted sites • Prepare the site• Place Ag/Cl reference electrodes

• Ring Electrodes [preferred]• Disc Electrodes [<10 mm]

• Ready to read patient action potentials• 0-6 mV [Typical]

sEMG Preconditioning

Sensor Device

Tactile Pressure SensorSensor FSR 400 A301

Manufacturer Sparkfun Electronics Tekscan

Sensing Area 0.3” 0.375”

Force Range 0-10 lbs 0-25 lbs

Response Time 1-2 usec <5 usec

Price 5.95 USD 16.25 USD

Image

Pressure Sensor Conditioning

• Standard Resistance from sensor (FSR):– Appr. 1 MOhm

• VREF should be negative– Appr. -5 Volts

• The smaller RG is the more sensitive the sensor becomes

Inverting Amplifier

Vout = (Vref)*(RG/Sensor)

Sensor Device

Flexible Potentiometer SensorSensor FS7548 SoftSpot

Manufacturer Spectra Symbol Spectra Symbol

Length 114 mm 100 mm

Thickness .48 mm .51 mm

Resistance Range 1 KOhm – 100 KOhm 1 KOhm – 10 KOhm

Price 14.95 USD 12.95 USD

Image

Bend Sensor Conditioning

• Standard Resistance from sensor (FSR):– Appr. 10 KOhm

• VREF should be negative– Appr. -5 Volts

• The more the sensor bends the more the greater the impedance

Inverting Amplifier

Vout = (Vref)*(RG/Sensor)

Sensor Device

Power Distribution

Overall Block Diagram

Specifications

Tablet Device

Dimensions 10” x 6 ¾” x 2”

Battery 4000 mAh, 5V

Up Time 4 Hours

Idle Time 8 Hours

Data Transmission Bluetooth 4.0

Wireless Range <50 meters

Screen Resolution 1024 x 600 pixels

Main Device

TouchscreenParameter Specification

Diagonal Size 10.1”

Aspect Ratio 16:9

Resolution 4096 x 4096

Accuracy ±1.5 %

Transmissivity 90 %

Active Current 6 mA

Sleep Current 94 µA

Digital Power Supply 3.3 VDD

Touchscreen ControllerCustom I2C

Voltage-level Shifter

Pandaboard ES J6Expansion Header

GND

SCL

SDA

VIO

Main Device

TFT-LCDParameter Specification

Diagonal Size 10.1”

Frame Rate 60 Hz

Resolution 1024 x 600 pixels

Maximum Power Consumption 2.6 W

Maximum Backlight Power Consumption 1.5 W

Thickness 0.5 mm

Digital Power Supply 3.3 VDD

IDD Current 240 mA

LCD Controller

LED BacklightControl I/O

30-pin LVDSConnection

LCD I/O

Pandaboard ESJ3/J4

Main Device

Pandboard ES

Features

Dual Core ARM Cortex A9 (1.2 GHz)

Graphics support (ex: OpenGL)

LCD expansion header

1 GB low power DDR2 RAM

SD card slot

General I2C expansion headers

802.11 b/g/n (WiFi)

Bluetooth 4.0

Awesome support community!

Pandaboard ES

Main Device

Tablet Power

• 6 volts 10000 mAh• 23 x 99 x 71 mm• $15-17

Tablet Software• Ubuntu• C++• qT

Monitoring Screen

Bill of Materials (Tablet)

Item Cost

10.1” TouchScreen Free

10.1” TFT-LCD Display $41.89

LVDS Cable $9.88

LCD Controller Expansion $57.18

Pandaboard ES $180.48

Power adapter (dev) $16.99

2.45mm pitch male pin headers $6.46

USB to RS-232 adapter (dev) $7.00

HDMI to DVI cable (dev) $4.56

8Gb SD card Free

Bill of Materials (Sensors)

Item Cost

sEMG Electrodes FREE

Pressure Sensor $5.95

Bend Sensor $12.95

Rotary Potentiometer $1.75

Low Noise Op Amp x 3 $2.32

Differential Amp $10.25

CC2450 Developers Kit (2 Modules) $289.75

PCB Cost (Expected) $70.00

Misc (Resistors,Capacitors,Diodes,etc) Free

Bill of Materials (Total)

Device Total Cost

Main Device (Tablet) $324.44

Sensor Device $392.97

Shocking Device $70

Running Total $787.41

Progress

Coming Soon?

• Finish prototyping• Finalize sensor PCB schematic for printing• Program microcontrollers• Sync Bluetooth devices• Integrate tablet parts• Software development• …Profit

Questions?