This document describes the development of a weight-bearing sensor device for orthopedic patients. It lists the materials needed and provides step-by-step instructions to assemble the sensor, which uses copper plates attached to shoe insoles to detect weight and trigger a doorbell chime. It also describes enclosing the sensor in fabric and attaching velcro to allow the device to be secured to the patient's shoe. The total cost to make one device is approximately $41.
2.
Clients with non-weight bearing precautions
in lower extremity
Orthopedic Surgeries
◦ Total Hip Replacement
◦ Total Knee Replacement
3.
Weight bearing restrictions are needed to
provide adequate time for proper bone
healing. It helps the hardware that was placed
during the surgical procedure to stay in the
correct place.
Understanding verbal instructions of these
precautions is hard for patients to
understand.
4. Material
Cost
Can Purchase at:
Shoe Insoles (pack of 4)
$1.99
Wal-Mart
22 gage wire
$1.06
Amazon
Doorbell Kit
$15.97
Wal-Mart
1/8” mono plug
$.97
Radio Shack
1/8” mono jack
$.97
Radio Shack
1/8” heat shrink tubing
$3.30
Radio Shack
Plasti Dip Spray
$5.98
Lowes
Muslin Fabric
$1.99/ft
JoAnn’s Fabric
36 gage copper roll (1/5 used)
$13.99/
12”x30’
JoAnn’s Fabric
Sticky Back Velcro (1/2 used)
$7.49
JoAnn’s Fabric
Packing Foam
$.50/ft
Pack N Mail
Electrical Tape
$.99
Menards
Hair Clip
$.50
JoAnn’s Fabric
Approximate Cost for 1 Device: $41.19
15.
Make sure the
electrical tape
covers all edges of
the metal slightly
Place one side of
the sensor on top
of packaging foam
and outline using
permanent marker
22.
Do not cover insole sensor with fabric prior
to testing electrical connection and the
amount of force required to trigger alarm
Foot sensor as shown requires
approximately 10 pounds to activate
If you want more weight to trigger the alarm
make the holes in the packing foam smaller
If you want less weight to trigger the alarm
make the holes in the packing foam larger
24.
Place small flat tip
screwdriver in slot
labeled open,
gently lift top cover
25.
Remove the
protective plate by
unscrewing the two
retention screws
using a small
screwdriver.
Set protective plate
aside and remove
circuit board
26.
Strip both ends of 2
strands of 22 gage
wire using a wire
stripper
27.
On the back of the
circuit board locate
the two connections
to the button that
activates the
doorbell chime
Solder 1 of the 22
gauge wires to each
of these
connections
29.
Drill a hole through
the back of the
wireless door
switch using a
Dremel
Hole placement and
size will depend on
the how big the
wires are exiting
the back
30.
Feed soldered wires
through the hole in
the back of the
wireless doorbell
switch
Reassemble switch
by replacing
protective cover
and top cover
31.
Apply hot glue
using a glue gun
around the back
hole in the wireless
door switch to
secure the wires in
place
35.
Hot glue gun a
metal hair clip onto
the back of the
door bell switch.
The clip is used to
secure the doorbell
switch to the
client’s shoe
36.
Perform a test of the device at this time by
plugging mono plug into mono jack
Make adjustments as noted in the “foot
sensor suggestions section”
37.
38. 1. Trace around foot sensor using
a marker
2. Cut the muslin fabric about
an 1” bigger then the marked
outline
39. 1. Pin together two cutout patterns 2. Sew approximately 1/8” away
from traced line 3. Leave enough unsewn gap to slide sensor in the case.
Also, leave small unsewn hole in toe area for wires to exit. Size *Will vary
depending on type and size of insoles purchased.
40. 1. Slide muslin sleeve over sensor.
Feed wire through the hole left in
the toe of the sleeve
2. Hand sew the rest of the cover
so that the sensory is fully
enclosed.
41. 1. Spray muslin fabric with Plasti
Dip Spray. Apply at least 4 coats.
Between coats let dry 30-45
minutes. Follow application
instructions on spray bottle.
2. Once dry place a piece of ¼” –
½” sticky back hook Velcro on both
sidesof the sensor.
42.
To keep floor side Velcro from sticking to
floor when not in use add a piece of loop
Velcro over the hook Velcro
43.
44.
Apply sticky back
loop Velcro to the
bottom of client’s
shoe
Attach sensor to
the bottom of shoe
Insert foot sensor
plug into doorbell
jack
Clip doorbell
switch to the
client’s shoe laces