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The
schematic
show
that the
AccelR8
only
uses 3
IC's. An
AVR 8515
microcontroller
do the
calculation
work and
controls
the
other
circuits.
An
MAX603
controls
voltage
and
power-on/power-off.
And the
chip
that
makes it
all
possible,
the
ADXL202
from
Analog
Devices
measures
the
acceleration.
This
chip is
a small
wonder.
It uses
a tiny
micro
machined
polysilicon
structure
on the
silicon
wafer.
The
structure
is part
of a
capacitor,
so
deflection
of the
structure
(by
acceleration)
can be
measured.
The
ADXL202
can
measure
acceleration
in two
axes,
and if
you have
a
Microsoft
Freestyle
Gamepad,
you
already
have an
ADXL202
!
In this
case, we
only use
one of
the
axes,
and the
ADXL202
outputs
this
data as
a
variable
duty-cycle
squarewave.
The 8515
calculates
the
acceleration
by
measuring
the
pulsewidth/period
relationship.
The
acceleration
is then
used in
further
calculations,
and the
resulting
data is
show on
the
display.
Click
here for
more
detail
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