U.S. patent application number 11/372722 was filed with the patent office on 2007-09-13 for wireless, solar-powered, pavement temperature sensor.
This patent application is currently assigned to ThomTech Design, Inc.. Invention is credited to Gregory E. Thompson.
Application Number | 20070211782 11/372722 |
Document ID | / |
Family ID | 38478896 |
Filed Date | 2007-09-13 |
United States Patent
Application |
20070211782 |
Kind Code |
A1 |
Thompson; Gregory E. |
September 13, 2007 |
Wireless, solar-powered, pavement temperature sensor
Abstract
An improved roadway temperature monitoring system is designed to
be powered by solar energy for measuring and transmitting sensed
roadway surface temperatures over a wireless link to remote
workstations comprises a module housing fabricated from a
light-transmissive, thermally conductive tough plastic for
containing a solar cell array, a microprocessor, a spread spectrum
RF transmitter, a plurality of temperature sensing elements and a
battery supply therefor whose charge is maintained by the solar
cell array.
Inventors: |
Thompson; Gregory E.; (St.
Paul, MN) |
Correspondence
Address: |
NIKOLAI & MERSEREAU, P.A.
900 SECOND AVENUE SOUTH
SUITE 820
MINNEAPOLIS
MN
55402
US
|
Assignee: |
ThomTech Design, Inc.
St. Paul
MN
|
Family ID: |
38478896 |
Appl. No.: |
11/372722 |
Filed: |
March 10, 2006 |
Current U.S.
Class: |
374/120 ;
374/E1.004; 374/E1.005; 374/E1.018 |
Current CPC
Class: |
G01K 1/14 20130101; G01K
2217/00 20130101; G01K 1/024 20130101; G01K 1/026 20130101 |
Class at
Publication: |
374/120 |
International
Class: |
G01K 1/16 20060101
G01K001/16 |
Claims
1. A self-contained roadway temperature monitoring module,
comprising: (a) a housing comprising a block of light-transmissive
material having a top surface, a bottom surface and a side surface
of a predetermined height dimension, the bottom surface having a
cavity formed therein; (b) a solar cell array disposed in the
cavity proximate the top surface for producing an electrical
potential at a pair of output terminals; (c) a microprocessor
disposed in the cavity at a location between the solar cell array
and the bottom surface, the microprocessor having a plurality of
data input terminals; (d) an RF transmitter disposed in the cavity
and coupled to receive output signals from the microprocessor; (e)
means coupling the output terminals of the solar cell array to the
microprocessor and to the RF transmitter; and (f) a plurality of
temperature sensing elements embedded in said block proximate the
side surface, the temperature sensing elements being electrically
coupled to said data input terminals of the microprocessor.
2. The module as in claim 1 and further including a DC battery
disposed in the cavity and coupled to receive a charging current
from the solar cell array with the battery delivering electrical
power to the microprocessor and the RF transmitter.
3. The module as in claim 1 wherein the temperature sensing
elements are thermistors.
4. The module as in claim 3 wherein the thermistors are disposed at
spaced-apart elevations within said predetermined height
dimension.
5. The module as in claim 1 and further including a plurality of
locator tabs projecting laterally from said top surface.
6. The module as in claim 5 wherein the locator tabs are removable
from the top surface following placement of the module in a opening
formed in the roadway, leaving the top surface of the module flush
with a top surface of the roadway.
7. The module as in claim 1 wherein the microprocessor is
programmed to control the transmission of sensed temperature
information to a remotely located receiver by said RF
transmitter.
8. The module as in any one of claims 1-7 wherein the cavity is
hermetically sealed by a thermally conductive potting compound
impervious to moisture.
9. The module as in claim 7 wherein the RF transmitter is a spread
spectrum transmitter.
10. A method of detecting whether a paved road surface is being
heated from above or below, comprising the steps of: (a) installing
a temperature monitoring module of claim 4 in an opening formed in
a roadway with the top surface of the housing flush with the paved
road surface; (b) providing a transceiver at a roadside location
within range of the RF transmitter; (c) transmitting temperature
readings obtained from said temperature readings obtained from said
temperature elements from the RF transmitter to the transceiver;
(d) forwarding the temperature readings to a remote computer
workstation, the computer workstation programmed to process the
temperature readings from individual spaced-apart temperature
sensing elements and determining from the readings the direction
from which the road surface is being heated.
Description
BACKGROUND OF THE INVENTION
[0001] I. Field of the Invention
[0002] This invention relates generally to temperature telemetering
apparatus, and more particularly to an electronics module adapted
for placement in an opening drilled into the surface of a pavement
for sensing pavement surface temperature and telemetering
temperature readings to a remote receiver whereby a determination
can be made whether to apply anti-icing chemicals to the
roadway.
[0003] II. Discussion of the Prior Art
[0004] In U.S. Pat. No. 6,695,469 to Leonhardt and assigned to
Energy Absorption Systems, Inc., there is described a roadway
freezing-point monitoring system including a module adapted to be
inserted into a opening drilled in the roadway pavement surface
such that the top surface of the module is flush with the roadway
surface. Contained within the module is a thermal-couple
temperature sensor, a random access memory, a read-only memory and
a memory controller. The memories and memory controller receive
power over a pair of wires in the cable 18. Cable 18 also includes
a conductor over which digital data may be sent to an external
roadside base station. Several such modules may be coupled via hard
wire connections to the base station which, in turn, is coupled via
a network to a remote computer.
[0005] The system described in the Leonhardt '469 patent is
operative to provide information to personnel at a remote site of
the need, if any, for applying freezing point reducing chemicals to
the roadway surface at particular locations to avoid formation of
ice on the roadway surface.
[0006] The modules described in the prior art Leonhardt '469 patent
suffer from the fact that a trench must be dug through the concrete
or asphalt road surface to accommodate the cable over which
electrical power is brought to the module from a roadside source
and over which digital data from the module to the roadside base
station is transmitted. The trench must later be filled with
patching cement or asphalt and this greatly increases the
installation cost. Moreover, if plural modules are disposed in the
roadway to monitor temperature in multiple lanes, it can adversely
affect the integrity of the road surface leading to break up due to
ingress of moisture and subsequent freezing and thawing action.
[0007] Another feature that is advantageous in a roadway
temperature sensing module is the ability to determine whether the
surface of the roadway is being heated from above, i.e., from the
sun, or is being heated from below, i.e., via the road bed.
[0008] This knowledge assists in the determination of what type of
anti-icing/de-icing treatment to employ and provides guidance on
the timing and location of the treatment. For example, if the sun
is shining, the road surface is being warmed from the sun, and the
forecast is for a nighttime air temperature just below freezing; a
suitable treatment would be to treat the roadway before sundown,
knowing that the sun and anti-icing/de-icing agent will work
together to melt the ice or remove the ice from the road surface.
However, if the sun is shining, the road surface is being warmed
from the ground, and the forecast is for a nighttime air
temperature just below freezing; it may be best to not treat the
road at all or to delay treatment until early morning, knowing that
the ground will assist in keeping the roadway surface free from
ice.
[0009] It is accordingly a principal object of the present
invention to provide an improved roadway temperature sensing
module.
[0010] Another object of the invention is to provide a
self-contained roadway temperature sensing module that does not
require operating power from a roadside location proximate the
module.
[0011] Yet another object of the invention is to provide a roadway
temperature sensing module capable of telemetering temperature data
from one or more sensing elements in the module to a remote
receiver station via wireless transmission.
[0012] Still another object of the present invention is to provide
a module adapted to be embedded in a roadway and that provides
multiple temperature sensing elements therein whereby the direction
of heating of the roadway surface can be determined.
SUMMARY OF THE INVENTION
[0013] These and other objects and advantages of the invention are
achieved by providing a self-contained roadway temperature
monitoring module that comprises a housing made of a block of
light-transmissive material and having a top surface, a bottom
surface and a side surface of a predetermined height dimension.
Formed in the bottom surface is a cavity in which is disposed a
solar cell array positioned proximate the top surface for providing
an electrical potential at a pair of output terminals. Located
beneath the solar cell array is a microprocessor chip. The
microprocessor chip has a plurality of data input terminals. Also
located within the cavity in the housing and coupled to receive
output signals from the microprocessor is a RF transmitter. The
output terminals of the solar cell array are appropriately
electrically coupled to the microprocessor and to the RF
transmitter so as to provide an operating voltage thereto. A
plurality of temperature sensing elements, e.g., thermistors is
embedded in the block comprising the housing proximate the side
surface and at different height elevations. These temperature
sensing elements are electrically coupled to the data input
terminals of the microprocessor. The microprocessor is programmed
to cause the RF transmitter or other wireless mode known to those
skilled in the art to sequentially transmit temperature readings
derived from the individual temperature sensing elements to a
remotely located receiver. From there, the data can be sent over a
network, e.g., the Internet to remotely located client computers
coupled to the network.
DESCRIPTION OF THE DRAWINGS
[0014] The foregoing features, objects and advantages of the
invention will become apparent to those skilled in the art from the
following detailed description of a preferred embodiment,
especially when considered in conjunction with the accompanying
drawings in which:
[0015] FIG. 1 is a perspective view of the wireless solar powered
pavement temperature sensor module constructed in accordance with
the present invention;
[0016] FIG. 2 is a cross-sectioned side elevation view of the
module of FIG. 1 showing the location of the plural temperature
sensors within the body of the module;
[0017] FIG. 3 is an electrical schematic diagram of the electronic
devices contained within the module of FIG. 1 and remote
receiver/transmitter for use therewith; and
[0018] FIG. 4 is a flow diagram of the algorithm by which the
direction in which roadway surface heating takes place may be
computed.
DESCRIPTION OF THE PREFERRED EMBODIMENT
[0019] Referring first to FIG. 1, there is shown a perspective view
of in-pavement temperature sensing module constructed in accordance
with the present invention. The module is indicated generally by
numeral 10 and seen to comprise a cylindrical block of a suitable
plastic, such as a polycarbonate, exhibiting superior thermal
conductivity properties and light energy transmittance. For
example, and without limitation, the thermal conductivity of the
plastic may be about 1.3 BTU-in/hr/ft.sup.2/degree F and a
transmittance through 1/10.sup.th in. thickness of the plastic of
about 88%.
[0020] As shown in FIG. 2, a cavity 12 is formed inward from the
base 14 of the module 10 and disposed within the cavity slightly
below the top surface 16 of the module is a solar panel 18. It
converts light energy into an electrical current that can be used
to charge a rechargeable battery cell 20 disposed upon a printed
circuit board 22 placed within the cavity 12. The printed circuit
board 22 is disposed beneath the solar panel 18 so as not to
obstruct passage of light through the top surface 16 of the module
from reaching the solar panel 18.
[0021] Also mounted on the printed circuit board 22 are a
microprocessor chip 24 and its associated memory. The
microprocessor 24 is used to control a spread spectrum RF wireless
transmitter which may also be mounted on the printed circuit board
22.
[0022] Referring momentarily to the schematic diagram of FIG. 3,
the microprocessor 24 includes an address bus 26 and a data bus 28
to which a read only memory 30 and a random access memory 31 are
connected, along with an input/output interface circuit 32. The
input/output interface circuit 32 receives input signals from a
plurality of thermistor temperature sensing elements labeled
T.sub.1-T.sub.4. These thermistors are physically located within
the module 10 at locations proximate the sidewall 11 of the module
at different height elevations measured from the base 14. The
thermistor T.sub.1 is located proximate the top surface 16 of the
module while the thermistor T.sub.4 is shown as being located
proximate the base 14 of the module. Thermistors T2 and T3 are
disposed at spaced apart locations between the thermistors T.sub.1
and T.sub.4, again proximate the outer wall of the module.
[0023] The microprocessor 24 is programmed to periodically sample a
temperature reading from the thermistors T.sub.1-T.sub.4 and
convert the analog temperature readings to a digital value which
can then be stored in RAM 31 and subsequently sent to the
transmitter 34. Transmitter 34 sends the data to a receiver 36
located on a pole at a roadside location within range of the
transmitter 34.
[0024] The receiver 36 may feed a longer range transmitter 38
broadcasting the data to a remote workstation on a LAN, such as the
Internet.
[0025] During manufacture of the module 10, it is provided with a
plurality of laterally extending ears 40 that extend horizontally
from posts 42 embedded in the plastic comprising the module
housing. When positioning a module in a bore drilled in the roadway
surface, the ears 40 support the module with the top surface 16
thereof flush with the surrounding roadway allowing backfilling of
the module with suitable epoxy filler. Once such epoxy filler has
cured, the ears 40 are broken off from the posts 42 leaving the
module 10 in the roadway with its top surface 16 flush with the
surrounding surface of the concrete or asphalt roadway surface.
[0026] During manufacture, following placement of the solar panel
18 and the printed circuit board 22 with its associated electronic
components thereon within the cavity 12 in the module 10, the
remaining space in the cavity 12 is filled with a suitable potting
compound 43 exhibiting good thermal conductivity. The potting
compound is preferably a thermally conductive epoxy,
environmentally suited for extreme climates, and rough treatment
from surface vehicles, temperature swings, and harsh chemicals and
precludes entry of moisture into the interior of the module which
could adversely affect the electrical circuitry contained
therein.
[0027] Without limitation, the module may be about 41/2 in. in
diameter and have a height dimension of about 13/4 in. Also,
without limitation, the transmitter contained within the module may
be a 450 MHz spread spectrum device that constitutes a purchased
component.
[0028] FIG. 4 is a flow diagram of a software algorithm that is
designed to be executed by the client workstation 39 using the
temperature data derived from the several thermistor temperature
sensors, T.sub.1 and T.sub.2, disposed in the module 10 to
determine whether the road surface is being heated primarily from
above, i.e., by the sun, or whether the road surface is being
heated by thermal transfer from the underlying road bed. If the
temperature reading from thermistor 1 is larger than the
temperatures received from the other three thermistors as
determined by decision block 50, a further test is made at decision
block 52 whether the temperature from thermistor number 4 is
smaller than the temperatures derived from the other three sensors,
T.sub.1-T.sub.3. If so, it is known that the road surface is being
heated by the sun or air from above (block 54).
[0029] Had the test at decision block 50 indicated that the
temperature reading from thermistor number 1 was not larger than
the other three, a further test is made at decision block 56 as to
whether the temperature from thermistor number 4 is larger than the
temperature reading from thermistors T.sub.1-T.sub.3. If it is, a
further test is made at decision block 58 as to whether thermistor
T.sub.1 is producing a temperature reading that is smaller than
that obtained from the remaining three sensors and if it is, it is
then known that the road surface is being heated from below as
indicated in block 60.
[0030] In either event, this knowledge derived from the analysis of
the temperature readings from all four thermisters is useful to
better control the timing, frequency, and amount of
anti-icing/de-icing treatment for the road surface. This
information, used in conjunction with other data, such as, weather
information (e.g. air temperature, barometric pressure, relative
humidity), type of anti-icing/de-icing agent (e.g. sodium chloride,
magnesium chloride, potassium acetate), and amount of previously
applied chemical, will determine the best treatment option for
maintaining a safe roadway. These contributing factors and knowing
the source of the roadway's surface temperature, are a major factor
in the optimizing the bond necessary between the agent and the
roadway maximizing the chemical's effect on breaking/melting the
snow and ice on the roadway or preventing ice formation. If the
road surface is warmed from ground, then treating the roadway the
same for several miles is appropriate because the treating chemical
is most affected by the surface temperature warmed from below. An
example of better decision making from this type of information is;
if the roadway surface is being warmed by the sun or the ambient
air temperature and the roadway temperature varies over distance,
then perhaps only the shaded from the sun areas will require
treatment.
[0031] Those skilled in the art can appreciate that many modules
like module 10 can be embedded at locations along a thoroughfare,
on bridges, entrances and exit ramps, etc., all effectively sending
temperature data to one or more workstations on the network,
thereby allowing supervisory personnel to dispatch highway
maintenance vehicles to those locations where an application of a
freezing point reducing chemical should be applied.
[0032] The present invention provides a solar-powered pavement's
temperature sensing module programmed for severe weather climates
that provides wireless transmission to a roadside receiver and
thereby replaces costly power and connection cables and also
eliminating trenching requirements. The elimination of the trenches
required by known prior art systems has been found to reduce
installation costs by a factor of 10. Because of the hardened,
rigidized construction, the module should survive in-pavement use
over a lengthy period of time.
[0033] This invention has been described herein in considerable
detail in order to comply with the patent statutes and to provide
those skilled in the art with the information needed to apply the
novel principles and to construct and use such specialized
components as are required. However, it is to be understood that
the invention can be carried out by specifically different
equipment and devices, and that various modifications, both as to
the equipment and operating procedures, can be accomplished without
departing from the scope of the invention itself.
* * * * *