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 50µV/Hz) or a high-precision
MEMS
accelerometer
(5µV/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)
· 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.