slide1 n.
Download
Skip this Video
Loading SlideShow in 5 Seconds..
Volume Measurement Research Update PowerPoint Presentation
Download Presentation
Volume Measurement Research Update

Loading in 2 Seconds...

play fullscreen
1 / 9

Volume Measurement Research Update - PowerPoint PPT Presentation


  • 98 Views
  • Uploaded on

Volume Measurement Research Update. Sukhi Basati PhD Candidate Laboratory for Product and Process Design Director: Andreas Linninger, PhD 8/25/2010. +. µC. actuator. -. sensor. Research Outline. An Implantable System for Intracranial Volume Measurements in Hydrocephalus.

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about 'Volume Measurement Research Update' - monita


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
slide1

Volume Measurement Research Update

Sukhi Basati

PhD Candidate

Laboratory for Product and Process Design

Director: Andreas Linninger, PhD

8/25/2010

slide3

+

µC

actuator

-

sensor

Research Outline

An Implantable System for Intracranial Volume Measurements in Hydrocephalus

  • Translational Research
    • Device can be designed with existing shunts
    • Catheter with ring electrodes
      • Designed as sleeve to fit around shunt catheter
  • Towards active control of Hydrocephalus
    • Feedback control of ventricular volume
    • Active vs. passive control systems
    • Simpler devices, less malfunction?
    • Addition of pressure transducers
  • New knowledge gained
    • Continuous measurements of volume
    • Can we validate p-v relationship
    • Future Studies on Tissue Compliance
    • Age dependence

Show microelectronic unit from prelim

slide4

Sine wave oscillator

Variable amp.

Voltage to Current Converter

Microelectronic Design

  • Requirements
    • AC signal excitation
    • Constant current
    • High SNR
    • Data acquisition

Instrumentation

Sensor

Resistor

Power

Brain (phantom)

Inst. Amp

G = Variable

  • Advantages
    • Adjustable current source
    • Adjustable frequency
    • Adjustable gain
    • Modifiable design
    • MCU integration

Microcontroller

(Power control + Digital signal out to RF transmitter)

RMS – DC Converter

Testing of instrumentation with decade box

Characteristics with Resistor Decade Box

slide6

1. Program LED on-off and put to sleep

  • 2. Analog-Digital Conversion
    • Store data in 8-bit register

3. Serial Data Communication

Methodology

How did I reach this milestone?

void main()

{

//initialization

TRISIO = 0b101110; //configure GP0 and GP4 as output

OPTION = 0b11001111; //set WDT timeout: prescaler assigned to WDT (PSA=1)

// WDT timeout = 2.3 s

CMCON0 = 7; //disable comparators

ANSEL = 0b00010100; //GP2 is only analog (pin 5)

ADCON0 = 0b00001001; // in ANSEL, put 001 in ADCS<2:0> bit for conversion clock

//put in ADCON0 register CHS<1:0> : read from AN2: 10

// in ADCON0 change ADFM (bit 7) to left justified : 0

// so most significant eight bits of data is in ADRESH

// change VCFG (bit 6) in ADCON0 (reference voltage) to 0

// and change ADON to 1 in (bit 0) of ADCON0 register

// so ADCON0 should look like: 00001001

for (;;) {

LED1 = 1;

delay_ms(4);

GODONE = 1; //start conversion

while (GODONE) //wait until done

;

synch_out(85);

delay_ms(1);

ser_out(ADRESH);

LED1 = 0;

delay_ms(12);

}

}

Steps taken to reach objective:

slide7

0

Start bit

Brief Explanation of Serial Data Communication using RS-232 Protocol

  • Very old protocol, much more advanced wireless systems exist today.
    • Who cares?
  • Receiver and Transmitter must “talk” to each other.
    • Both are 434 Mhz RF transmitters. (okay for animal testing)
  • The transmitter emits a synchronization byte (8 bits) followed by a brief delay, and then the register with the analog-digital converted values (8 bits) is sent.

transmitter

0

1

0

1

0

1

0

1

0

Receiver looks for “U” then records any data after the start bit

Start bit

Data (8 bits)

Synch bit

Reads: 01010101

Decimal for 85, character value of “U” (see ASCII table)

slide8

Future Goals

  • Include Battery, and include sleep mode with microcontroller.
    • Also need to consider some sort of battery clip to PCB, and a metallic case enclosure to also act as an antenna.
  • Test device for long term (1 day, week, month).
  • Scale down instrumentation on printed circuit board.
    • First using through-hole components, then ultimately designed a surface mount PCB.
  • Additional sensors can be easily integrated with microcontroller (still have 3 A/D ports).
  • Fabricate additional sensors (large, small) and test with new electronics.
  • Coat sensors in parylene.
  • Test in acute rat HC model.
slide9

Proposed Fall 2010 Plans

  • Submit Rat HC Measurement Paper to JNS-Pediatrics
    • Priority: Medium
  • Fabricate Microelectronic Unit for Long Term Measurements
    • Priority: High
  • Perform Sensor Simulations (Positional Dependence)
    • Priority: Medium
  • Submit Grant
    • Priority: High