Detailed Design Documents directory.
Finalized designThe 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.
The Boost Converter Schematic is shown below.
The Buck Converter Schematic is shown below.
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.
Prototyping, Engineering Analysis, Simulation
The team came up with a preliminary list of assumptions
AnalysisFeedback 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 continuedThe 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
An in depth button analysis can be viewed here
CDP'sThe CDP's for mechanical engineers can be found here
The CDP's for electrical engineers can be found here
SME feedbackFeedback from Professor Carlos 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
The following images are of an early revision of the cane in CAD.
Here is a more up to date revision of the cane assembly.
The following image of a roller assembly done using CAD.
The following image is of the motor drawn in CAD. The final design will incorporate two of these.
The following image is of a tentative PCB design layout.
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.
BudgetTo view a full breakdown of the budget click here
The sensor test plan can be seen here
The mechanical engineering test plans can be found here
Accelerometer test plan here
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 ReviewsTo view the final design review | click here
Moving ForwardTo view EE design moving forward click here
To view ME design moving forward click here
To view IE moving forward ideas click here