P15043: Smart Cane Systems Integration
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Detailed Design

Table of Contents

Detailed Design Documents directory.

Finalized design

The finalized design will incorporate a single sensor, a single lithium ion battery, a buck (Charging IC) and boost converter, and two motors.

The CAD image for the handle can be seen below.

Handle layout#nofilter

Handle layout#nofilter

The Boost Converter Schematic is shown below.

Boost Converter#nofilter

Boost Converter#nofilter

The Buck Converter Schematic is shown below.

Buck Converter#nofilter

Buck Converter#nofilter

Haptic Feedback Detailed Description

There will be two bearing feedback assemblies attached to the cane handle, one on the right hand side of the cane and one on the left hand side. The user will hold the cane so that their right pointer finger is along the flat edge of the handle. Based upon this hand placement, the right side bearing will be pressed against the user’s palm, while the left bearing is in contact with the user’s middle and ring fingers. One sensor on the front of the cane will detect objects in the user’s path. Because the user’s will sweep their cane, an accelerometer will be included in the handle to enable the sensors to distinguish what side of the user an obstacle is on.

If the user approaches an obstacle on their left, the left side bearing assembly will slide the bearing back and forth across the user’s fingers. This will indicate to the user that there is an object on their left. The feedback will continue until the object is no longer in their path. Similarly, if the user approaches an obstacle on their right, the right side bearing will be activated and the bearing will slide back and forth against their palm. This feedback will also continue until the object is no longer in their path. If there is an obstacle on the right and left of the user, both bearing assemblies will activate simultaneously and each will separately shut off when their respective side no longer has an obstruction.

Haptic Feedback Concept Evolution Flowchart

Prototyping, Engineering Analysis, Simulation

The team came up with a preliminary list of assumptions

Assumption list

Assumption list

Analysis

Feedback magnitude discussion here

Rough length measurement for cane here

An analysis of the button location can be viewed here here

An analysis of ergonomics done by the IE's can be viewed here

An analysis of roller bearing feasibility can be viewed here

An analysis of the cane length can be viewed here

Benchmarking continued

The motor bench marking can be found here

The 3D filament bench marking can be found here

Bench marking for rechargeable battery packs can be found here

Bench marking for individual rechargeable battery packs can be found here

Bench marking for several different sensors can be found here/Sensor EZ 4 datasheet/Sensor EZ 0 datasheet

An in depth button analysis can be viewed here

CDP's

The CDP's for mechanical engineers can be found here

The CDP's for electrical engineers can be found here

SME feedback

Feedback from Professor Carlos here

Feedback from Dr. Cormier can be viewed here: IE: here ME: here

Feedback from Marshall can be viewed here

Feedback from Dr. Walter can be viewed here: View/Download

Feedback from Fisher Price can be viewed here

Drawings, Schematics, Flow Charts, Simulations

Code flow chart for micro controller

High Level

High Level

The following images are of an early revision of the cane in CAD.

Collage of cane Rev1 #nofilter

Collage of cane Rev1 #nofilter

Here is a more up to date revision of the cane assembly.

Collage of cane Rev2 #nofilter

Collage of cane Rev2 #nofilter

The following image of a roller assembly done using CAD.

Roller assembly

Roller assembly

The following image is of the motor drawn in CAD. The final design will incorporate two of these.

Motor in CAD

Motor in CAD

The following image is of a tentative PCB design layout.

PCB design layout#nofilter

PCB design layout#nofilter

Bill of Material (BOM)

The updated BOM (12/8/14) can be viewed here.

The team has created this template for their bill of materials and they anticipate to populate this document throughout weeks 10 to 14.

Budget

To view a full breakdown of the budget click here

Test Plans

The sensor test plan can be seen here

The mechanical engineering test plans can be found here

Accelerometer test plan here

Risk Assessment

Motor vibration mitigation can be found here

Handle repair mitigation can be found here

Risk assessment of the motor change can be found | here

Design Reviews

To view the final design review | click here

Moving Forward

To view EE design moving forward click here

To view ME design moving forward click here

To view IE moving forward ideas click here


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