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Front view of a nicely equipped Universal Sensor
Platform (WISAN 2 node not installed).
High precision
MEMS
accelerometer
Low-power 3D
MEMS
accelerometer
Gain and offset
compensation
JTAG
interface
Low-noise 5V
supply
Output
buffer
Micropower
low-noise
filter
Programmable
anti-aliasing
filter
Micropower
low-noise
filter
Terminal for
external single-
ended sensors
Programmable
anti-aliasing
filter
Terminal for
external
differential
sensors (strain)
Buffered
output to
actuators
Micropower
EMF-protected
instrumental
amplifier
Wide gain range EMF-
protected instrumental
amplifier

Universal Sensor Platform enriches capabilities of WISAN 2 sensor
nodes by providing built-in acceleration sensors and interfaces to a
variety of off-the-shelf sensors and actuators.
Universal Sensor Platform (USP) provides a diverse selection of configuration
options supporting built-in and external sensors and actuators.
Optional features allow for over a
hundred
different
configurations
that can be marketed as a line of
products.
Two options are provided for
internal accelerometer sensors either a
low power 3D MEMS accelerometer
(noise 50V/Hz) or a high-precision
MEMS
accelerometer
(5V/Hz).
Accuracy of the sensors was validated in
laboratory
experiments
against
a
scanning Laser Doppler Vibrometer.
Two
options
are
provide
for
optional anti-aliasing filters (24-bit ADC
has a 3
rd
order filter) micropower with
fixed
cutoff
frequency
and
programmable
filter
with
software-
configurable cutoff frequency
Optional
gain
and
offset
compensation stage improves resolution
External single-ended sensors can
be connected to an optional power-
controlled terminal (3.3V, 5V)
Two options are provided for
external
differential
sensors
a
micropower instrumental amplifier (gain
range
5-1000)
or
a
wide
range
instrumental amplifier (gain 0.1-10000)
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Optional buffered output terminal
allows sourcing of control and excitation
signals
USP can be used with WISAN 2
sensor nodes with or without 24-bit
ADC. Provisions to use 12-bit ADC are
kept for less expensive and less precise
configurations. Optionally populated on
WISAN 2 sensor nodes, a 24-bit ADC can
be used for applications requiring high
precision.
Form-factor of the board allows
use of commercially available NEMA4
enclosures.
A quarter- or half- wavelength
whip antenna fits inside of the enclosure, not requiring an outside connection
Status LEDs can be observed through transparent lid
Voltage reference for instrumental amplifiers can either be sourced from 24-bit
ADC or a stand-alone precision reference
All circuits feature shutdown inputs, so a part or the whole USP can be put into low-
power sleep mode.
































06/25/2006
Hermetically sealed enclosure with built-in acceleration
sensor and external strain sensor
Minimally populated USP
(WISAN 2 node is not
installed) in configuration with
a vibration sensor
Block-diagram of USP. ADCs and DAC are installed on WISAN 2
sensor node.