Automated Maze System Development Group 9 Tanvir Haque Sidd Murthy Samar Shah Advisors: Dr. Herbert Y. Meltzer, Psychiatry Dr. Paul King, Biomedical Engineering

Introduction  Microdialysis Method of measuring physiological activity during task Dr. Meltzer’s Lab uses it to study brain activity during memory tasks

Experimental Setup  Rat hooked up to Microdialysis  Rat placed in Maze, performs memory tasks  Sample collected during maze run  Sample Analyzed for content

Problems  Dialysis tubes’ entanglement  Rat’s recognition of overhead device psychological repercussions  Manual guiding of tubes cumbersome for researcher

Constraints  Maze Dimensions  Rat Size  Rat Speed  Rat Cognition  Tube Length  Dialysis Weight Depth: 18”

Primary Objective To develop a fully independent research module that facilitates the study of memory

System Description Acquire Mouse Position Determine Change in Position Translate Dialysis Machine

Position Acquisition MethodProsCons Camera  High Resolution  Real-Time feedback  Software intensive  Mounting Issues  Processing Limitations  $1,355 Sensor  Manageable data  Less processing  $1,160  Low resolution  Center of maze difficult to map

Image Processing Acquire ImageCalibrate the Image Convert the 32 bit image to an 8 bit image Filter Image 1: Remove Border Objects Filter Image 2: Remove Small Objects Pattern Match to a Specified Image Determine the pixel at the center of the pattern Translate pixel value into physical coordinates Output Physical coordinates in array form

LabVIEW Software Code

Image Processing Unprocessed ImageProcessed Image

LabVIEW Screen Shot

Choosing a Microprocessor Motorola 68HC11E  One 8-bit input  Low cost  On board A to D converter  $200 NI PCI-7342  Four 8-bit inputs  More processing capabilities  Software Compatibility with LabView  $895

Processing the Information  Continually Given one set of coordinates (X,Y)  Compares the coordinates of (X n-1,Y n-1 ) to (X n,Y n ), computes the difference, and rounds the significant digits  Converts the difference into specified timed waveform for the driver  Driver amplifies signal and controls motor speeds

Drive System  Lead-screw Device Easy to build Inefficient $1,  Pulley/Belt System Complicated System Efficient $6,000

The Lead-Screw Device Motor Driven Rotational Energy converted to Linear Energy

Device Apparatus

Driven by dual motor system Translation responds to mouse movements Open Loop Feedback

Choosing a Motor  Design Considerations: Speed of Mouse: 2 ft/s Torque  Torque needed to drive apparatus  Torque needed to provide acceleration  Stepper Motor or DC Motor?

Speed Lead (in/rev)RPM RPM = 25.5 in/s / Lead*60 s/min Target RPM Range

Torque  Driving Torque  Acceleration  Driving Torque 2 ft/s L = 2.37 lbs P =.5 in/rev e f =.4 (for ACME) T f = 53 mNm Position Time 25 in -25 in I = lb-in-s 2 α = 265 rad/s 2 T = 36 mNm Worst Case Scenario

Stepper or DC?  Stepper Torque < 3.53 Nm RPM < 2000  DC High Torque High RPM

DC Motor  3000 RPM (using 0.5 lead)  87 mNm Torque  Powered by Driver  Monitored by external Optical Encoder

Flow Chart Image Calculate Δ(x,y) Micro- Processor Driver Motor Translation Image Calculate Δ(x,y) Micro- Processor Driver Motor Translation

Budget Support Scaffolding$99.70 Mechanical Arm (including driver electronics) $ Microcontroller$ Labview/Imaging Software$1, Grand Total$

Departmental Reconsiderations Budget limitations caused the psychiatry department to reconsider the value of their experimental setup. Thus, our design, though it was considered valuable by the department, was not approved.

Contingency plan  Develop a model which represents fundamental principles of design  Image acquisition system demonstration – LabVIEW software  Mechanical arm system demonstration – Erector set

Overall Status  Developing Theoretical Model  Next step: Final Report and Poster Board Month/ TasksJanuaryFebruaryMarchApril Breakdown of parts needed Researched parts and obtained quotes Offer proposal for parts Develop theoretical model Build theoretical model Work on Poster Board Work on Final Report

Conclusion Though no tangible design will be developed, a better understanding of image acquisition systems, micro- processing and linear actuators was obtained With the development of the theoretical model, the perceived design was realized and used for its educational purposes