eShoe: Fall Prevention in elderly submitted for FLL by CoolCATS

1. Preventing Falls
In The Elderly
By CoolCATS
(Team # 11964)
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2. Problem Definition
Falls are common in the elderly, and frequently result in
injury, disability, and institutionalization
Falls occur in about one third of elderly living
independently in the community every year1
Visual impairment is a major risk factor for falls2
Reduced contrast sensitivity and depth perception
are the most important visual risk factors for falls
Adequate depth perception and distant-edge-contrast
sensitivity appear to be critical for maintaining balance
and detecting and avoiding hazards in the environment
Lead to significant physical, psychological and financial
costs to the individual and the community
(1) http://www.ncbi.nlm.nih.gov/pubmed/11769782
(2) http://www.ncbi.nlm.nih.gov/pubmed/16083415
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3. Contrast Sensitivity
Contrast is created by the difference in
luminance (the amount of reflected light)
reflected from two adjacent surfaces
Contrast sensitivity measures the ability to
see details at low contrast levels
In orientation and mobility, it is important to
recognize such critical low-contrast forms as
the curb, faint shadows, and stairs when
walking down
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4. Depth Perception
Depth perception is the ability of the human eye to see
an object in three dimensions (length, width and height)
The ability of both eyes to focus on one object and the
ability to recognize shapes and sizes, tell the brain
where objects are in relation to other objects
Recognition of object location is essential for almost all
activities
navigating/avoiding objects
catching/throwing
reaching/grasping
size judgments and recognition
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5. 3
Existing Solutions
Vision therapy
Single Vision Prescription Glasses
LASIK surgery
Vision correction surgeries
Contact Lenses
Combination of two or more of the above
solutions
(3) http://www.cmellc.com/geriatrictimes/g031209.html
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6. Problem with existing solutions
Need two or more single vision glasses, for
instance different glasses for near and far vision
Multifocal glasses can not be used as it may add
to this risk because their near-vision lenses
impair distance contrast sensitivity and depth
perception4
None of currently available corrective lenses or
surgical techniques can completely restore the
dynamic focusing flexibility, therefore depth
perception
(4) http://ageing.oxfordjournals.org/content/35/suppl_2/ii42.short 6

7. The Solution: eShoe
An electronic device to alert seniors of any
obstacle in their path such as bumps and
holes
Should be simple to use and affordable
Should have longer battery life & easy to
charge
Could be wearable (on clothes,
shoes/slippers, canes, gloves, etc.)
Provide at least a proof of concept of the
device implanted in slippers/shoes
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8. Different ways of detecting obstacles
Three-dimensional (3-D) imaging
Complex and Expensive
Laser (Optical) method
Pros
Precise measurement
Cons
Shape recognition of a transparent object is difficult
Expensive
Ultrasonic sensor method
Pros
Simpler and Cheaper
Cons
Measurement is not precise (sound is far more difficult to focus than light)
Can not detect small objects and certain shaped objects (like narrow pipes)
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9. How does eShoe detect obstacles?
Uses an ultrasonic sensor or sensor arrays
for detecting obstacle5
Proven technology used in robot obstacle
avoidance systems
Works on principle that bumps and holes
reflects the sound but flat surface doesn‘t
(5) http://ieeexplore.ieee.org/
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10. How does eShoe detect obstacles?
Ultrasonic waves are sound waves which can
get reflected by any objects on its path
The delay between sending and receiving
reflected waves tells how far the obstacle is
Triangulation6 technique can also be used
with 2 sensors to get more precise detection
The processing of sensor information is done
using a low cost micro controller
(6) http://ieeexplore.ieee.org/ 10

11. High Level Design
Miniature Switch
Buzzer
Rechargeable
Battery
Microcontroller Vibrating Micro Motor
Charger
Ultrasonic Sensor
Circuit
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12. High Level Design (Cont)
The above circuit is implanted in
the shoe in such a way that it
can withstand 200 pounds
The shoe can be recharged
wirelessly using a charging pad
When switched on it will
calibrate for distance and go
into low battery mode until it
finds an object
It buzzes and/or vibrates when it
detect any obstacle
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13. Proof of Concept
Used a gadget called Park-Zone
available on market for car parking aid
This gadget uses ultrasonic sensor to aid
car parking in garage
Modified the gadget to use Buzzer
instead of LED
Mounted inside sole of a slipper
Tested with a senior who lives with the
condition and found to work with Bumps
reliably
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14. Limitations
May not detects holes reliably
Detection of holes depend on the shape of the hole
and its dimensions
Mounting angle of sensors are important to make
detection of holes
The gadget may additional weight to the shoe.
Large volume production could make this gadget
more thinner/compact and flexible enough to
mount on shoes
Outdoor detection might require improved
design
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15. Conclusion
Use the existing proven technology used in
obstacle finding robots
Low Cost solution: ~ $25/piece in 1000 pieces
volume production
Easy to charge and operate – wireless
charging: uses charge pad for recharging, just
park the shoe on charging pad
It can be enhanced to check for balance
impairment in elderly which is another cause
for most falls
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