ECE 477 Design ReviewECE 477 Design Review Group 9 Group 9 Spring 2005 Spring 2005

Omar Shaikh - Nathan Smith - Jeff Huston - Ryan Koors

Presentation OutlinePresentation OutlineG.I.M.P. overview G.I.M.P. overview Project-specific success criteriaProject-specific success criteriaSystem block diagramSystem block diagramComponent selection rationaleComponent selection rationalePackaging designPackaging designSchematic and theory of operationSchematic and theory of operationPreliminary PCB layoutPreliminary PCB layoutSoftware design/development statusSoftware design/development statusProject completion timelineProject completion timelineQuestions / discussionQuestions / discussion

Project OverviewProject Overview

General Informative Medical ProstheticGeneral Informative Medical Prosthetic

Integrable gait feedback system Integrable gait feedback system for existing lower limb prosthetic for existing lower limb prosthetic devices.devices.

Project-Specific Success CriteriaProject-Specific Success Criteria

1.1. … …detect pressure changesdetect pressure changes in the shoe via an ATD port in the shoe via an ATD port on a microcontroller and to on a microcontroller and to map those pressure map those pressure differentialsdifferentials to distinct to distinct vibrating patterns in a vibrating patterns in a vibrating motor strap. vibrating motor strap.

The ability to…

i

Success Criteria continued…Success Criteria continued…

2. …2. …execute sequential vibrating execute sequential vibrating patternspatterns, thus providing “how-to-walk” , thus providing “how-to-walk” training capabilities training capabilities

The ability to…

Human leg of cross-section

Success Criteria continued…Success Criteria continued…

3. …3. …record sensor data and upload to a record sensor data and upload to a computer via Ethernet connectivity computer via Ethernet connectivity

The ability to…

Data

uploading

Success Criteria continued…Success Criteria continued…

4. 4. display system status (mode, battery display system status (mode, battery level) on an LCD level) on an LCD

The ability to…

MODE:

Warning: Low Battery

LEARNING: Walking

Calibration

Success Criteria continued…Success Criteria continued…

5. …5. …automatically determine when the automatically determine when the prosthetic is idle and enter into a prosthetic is idle and enter into a power-conservation mode in which power-conservation mode in which certain functions/ports will be turned certain functions/ports will be turned off (some ATD, LCD, etc). off (some ATD, LCD, etc).

The ability to…

Note:

Does not reflect actual battery life

Block Diagram

Microcontroller

Amplifier Circuit

Shielded

cable

LCD

ATD

PORT

RESET

Reset Button

PORT

RPG

Ethernetdevice

NetworkApplications

(calib. and data upload)

Power Supply:

7.2Vdc RCcar battery

DC SwitchingRegulator

Power supply

+/- 5Vdc reg. 3.3 Vdc reg.

BJTamps.

Vibratingmotors

LEDs

Pressure Sensors

= on PCB

= off PCB

= plug connection required

KEY

Clinometer Fused 7.2 supply

Component Selection RationaleComponent Selection Rationale

FLEXIFORCE SENSORS:

Clinometer:

RationaleMain Components:

•Relatively inexpensive

•Flat and flexible

•Tried and true in previous senior design projects

•Easily-readable, non-discrete output

•Met durability requirements

Component Selection Continued…Component Selection Continued…

Vibrating motors:

HC12 NE64 Variant Microcontroller:

RationaleMain Components:

•Low current requirements

•Very inexpensive ($1.25 each)

•Flat shape for implementation

•Met I/O requirements (80)

•Integrated TCP/IP functionality

•64K Flash memory

Component Selection Continued…Component Selection Continued…

Description Vendor Part Number Unit Cost Quantity Total Cost

FLEXIFORCE SENSORS Tekscan A201-100 $13.75 4 $55.00

SENSOR CLINOMETER HORIZONTL FLNG AccuStar 02110102-000 $139.00 1 $139.00

VIBRATING MOTORS Sanko Electric 1E120 $1.25 10 $12.50

MC9S12NE64V1freescale semiconductor MC9S12NE64CPV $0.00 1 $0.00

Total (approximate): $600

Packaging DesignPackaging Design

Batte

ry

PCB

RPG

LCD

Peripheral Connections

4 in.

7 in.1.5 in.

Schematic/Theory of OperationSchematic/Theory of OperationPower Supply and Distribution:

Regulator circuits from regulator manufacturer website

5V

-5V

3.3V

7.2 V unregulated

Schematic/Theory of OperationSchematic/Theory of OperationMicrocontroller:

CRG module handles power regulation on reset

ATD pinsMotor PWMs

LCD pins

BDM header

Run/boot switch

Schematic/Theory of OperationSchematic/Theory of OperationMicrocontroller Headers:

Schematic/Theory of OperationSchematic/Theory of OperationPressure Sensor Circuits:

4 inverting integrator Amps with noise suppression caps on output

-5 V

100 K pots (R12,12,13,14)

Schematic/Theory of OperationSchematic/Theory of OperationPressure Sensor Circuits:

10 Class D amplifiers, all R values chosen so “ON” is always in saturation

Schematic/Theory of OperationSchematic/Theory of OperationConnectors, etc.:

Preliminary PCB LayoutPreliminary PCB Layout

Trial 1: Trial 1: Size: 5” X 3”Size: 5” X 3”COMPLETE FAILURE

Preliminary PCB LayoutPreliminary PCB LayoutTrial 2: Trial 2: Size: 7” X 4” (100% routed, 0 DRC errors)Size: 7” X 4” (100% routed, 0 DRC errors)

Only common GND between

A&D

Analog Amp. Circuits

Digital Circuits

Power SupplyATD Amp. Circuits

Software Design/Development StatusSoftware Design/Development StatusPre-Module Development StatusPre-Module Development Status

Pulse Width Modulator (PWM)Pulse Width Modulator (PWM) Analog-To-Digital (ATD)Analog-To-Digital (ATD) Hardware InterruptsHardware Interrupts Memory ManagementMemory Management Ethernet ConnectivityEthernet Connectivity

Module Development StatusModule Development Status Liquid Crystal Display (LCD)Liquid Crystal Display (LCD) Sensor Data Management (SDM)Sensor Data Management (SDM) Pressure and Clinometer Sensor InputsPressure and Clinometer Sensor Inputs Motor OutputsMotor Outputs Power Down Mode – Battery MonitorPower Down Mode – Battery Monitor Startup Mode – WatchdogStartup Mode – Watchdog

Project Completion TimelineProject Completion Timeline

•Schedule through user manual composition. (April 13)

Questions / DiscussionQuestions / Discussion