
69-11Human Occupancy Detectors
with the electrode that drugs the electric eld from the object. An elegant solution is to shield the
electrode from the arm by an intermediate shield as shown in Figure 69.9c. e sensor’s assembly is
a mu
ltilayer
co
ver
fo
r
th
e
ro
botic
ar
m,
wh
ere
th
e
bo
ttom
la
yer
is an in
sulator,
th
en
th
ere
is a la
rge
el
ectrically
co
nductive
sh
ield,
th
en
an
other
la
yer
of in
sulation,
an
d
on th
e
to
p
is a na
rrower
sh
eet
of
th
e
el
ectrode
. To re
duce
a ca
pacitive
co
upling
be
tween
th
e
el
ectrode
an
d
th
e
ar
m,
th
e
sh
ield
mu
st
be at th
e
sa
me
po
tential
as th
e
el
ectrode,
th
at
is
,
it
s
vo
ltage
mu
st
be dr
iven
by th
e
el
ectrode
vo
ltage
(hence t