WO2010011128A2

WO2010011128A2 - Apparatus for chemical sensing in harsh environment and method thereof

Info

Publication number: WO2010011128A2
Application number: PCT/MY2009/000100
Authority: WO
Inventors: Othman Masuri; Md Yusof Ismail
Original assignee: Mimos Berhad
Priority date: 2008-07-22
Filing date: 2009-07-21
Publication date: 2010-01-28
Also published as: WO2010011128A3

Abstract

The present invention discloses an apparatus and method thereof which is suitable for harsh environment, wherein it is able to provide a wide variety of measurements or detections and effective monitoring of sample of harsh environment. The collected data subsequently is converted to digital data and thus wirelessly transmitted to a suitable gateway, said gateway is preferably World Wide Web based.

Description

Apparatus for chemical sensing in harsh environment and method thereof

Field of Invention

The present invention relates to an improved chemical sensing apparatus and method thereof, more particularly to an improved chemical sensing apparatus and method which involves precise data acquisition in harsh environment.

Background of Invention

Currently, the microelectromechanical systems (MEMS) based devices, also known as Microsystems have gained tremendous momentum within the commercial markets for a wide variety of applications, whereby, the device categories or industries for which these devices are extensively used include fluidic MEMS, mechanical transducers, optical MEMS, and electrical MEMS.

In the MEMS based sensor industry, relevant innovators are focusing on developing significantly enhanced microsystem (MEMS) -based sensors particularly for improving measuring efficiency. One of the key challenges in developing a successful method for MEMS based sensors at present is the packaging aspect, whereby a person skill in the art appreciates that sensors, more particularly micron-sized devices, requires effectual packaging to withstand the harsh environment, in addition to corrosion. In such physical condition or environment, the MEMS based sensors packaging must be robust, despite the fact that the sensors must be in sufficient contact with the measurand, said measurand may include chemical ions, nitrate, phosphate, potassium and other components which the sensors are intended for.

The second significant factor that contributes to a successful MEMS sensor method is the efficiency in data acquisition or measuring capability. To date, most sensors may have effectual packaging but collect data manually, which is rather time consuming despite the fact that the data collected may not be reliable, particularly in harsh environment. This may be also owing to the fact that biological and chemical properties in harsh environment are highly influenced by a large scope of parameters ranging from pressure to acidity.

A relatively conventional example of packaging methodology and apparatus for MEMS sensors is as disclosed in US Patent No. 684 5664 (OKOJIE ROBERT S) . The said patent focuses on a plurality of methods for bulk manufacturing high temperature sensor sub- assembly packaging whereby sensors are sandwiched between a top cover and a bottom cover so as to allow the sensors, together with the covers to be securely bound prior to insertion into the final packaging. Whilst this methodology may be expedient for harsh environment, the said methodology exclusively concentrates on sensors packaging, and therefore not in providing precision in data acquisition by the sensors.

The findings in relation to data acquisition and collection tribulation led to the need for enhancement for the said aspect; and therefore puts forward continuous advances to further improve the data acquisition or collection aspect of MEMS sensors, and thus fulfill the sensor attributes by most end users. One of such enhancements is the introduction of Wireless Sensor Network (WSN) . In the WSN implementations, the signals transduced by the environmental monitoring sensors are wireless transmitted to the gateway for it to be forwarded to the World Wide Web based network. The said data is further processes can subsequently be employed for the closed-loop control.

It is therefore understood that the WSN alleviates the complications in regards to manual data collection which is considerably inefficient and can be prohibitively costly. The WSN technology is also expected to increase the yield and the quality of agriculture production. Notably, the increase in the said yield is highly significant in view of the global warming and the increase in world population at large.

An exemplary of the prior art concerning wireless systems and methods for monitoring is as disclosed in United States Patent Application No. US 2007152813. In the said invention, there is provided a method and systems for monitoring a plurality of parameters, in particular within process equipment. The parameters include temperature and pressure, whereby the wireless sensors transmit sensor signals to the receiver which is connected to a central monitoring unit for further processing. It is noted that the invention is more suitable for monitoring process equipment and may not be suitable for harsh environment.

The above circumstances have indicated that there is a need for a sensor apparatus and methodology thereof which comprise of excellent and thus robust packaging for harsh environment and altogether provides reliable data acquisition for users.

Owing to the fact that the recent development in the WSN and its applications in the agricultural and environmental monitoring have put forward the necessity to meet stringent requirements in relation to the sensor packaging prior to being deployed in harsh environments . It is therefore the primary object of the present invention to provide an apparatus and method thereof that effectively overcomes the aforementioned tribulations within the MEMS sensor industry.

It is the object of the present invention to provide a MEMS sensor apparatus and method thereof which is expedient for harsh environment .

It is yet another object of the present invention to provide a MEMS sensor apparatus and method which alleviates the complications in relation to manual data collection method.

It is further an object of the present invention to provide a MEMS sensor apparatus and method thereof which alleviates the complications in relation to sensor packaging, whereby the present invention allows the sensing elements (8) to be sufficiently in contact with the measurand.

Summary of Invention

The present invention discloses an apparatus for wireless sensing for use in measuring and monitoring a sample; said apparatus comprising: a first housing means (1) for accommodating at least one sensing element (8); a second housing means (3) attached to the first housing means (1) for accommodating and encloses a means for processing wireless signals (4, 4a, 6, 6a) from the sensing element (8) and a means for wirelessly transmitting (2, 2a) output from said means for processing signals to a gateway; wherein the sensing element (8) is positioned within the first housing (1) such that at least one end of the said sensing element (8) is secured to the first housing (1) and another end can be in contact with the sample

The invention further provides a method for measuring and monitoring a sample comprising the steps of: preparing an apparatus as described herein; detecting electrical, physical, chemical and/or biological property associated with the sample; converting data from detection to a digital signal; and wirelessly transmitting digital data to a gateway.

Brief Description of Drawings

The invention will be more understood by reference to the description below taken in conjunction with the accompanying drawings herein: Figure 1 illustrates the sensor apparatus in accordance with one embodiment of the present invention;

Figure 2 illustrates the sensor apparatus during use in liquid or water influenced sample.

Detailed Description of the Present Invention

In addition to the drawings and in line with the summary of the invention, further understanding of the object, construction, characteristics and functions of the invention, a detailed description with reference to the embodiments is given in the following to understand the inventive features of the present invention. It shall be apparent to one skilled in the art, however that this invention may be practiced without such specific details. Some of the details may not be described at length so as not to obscure the invention. For ease of reference, common reference numerals will be used throughout the figures when referring to the same or similar features common to the figures.

It is noted that the term "sensing element" used within the specification refers to sensors or suitable means for providing detection or measures properties of a sample and providing a signal based on said detection with respect to the preferred embodiments of the present invention. Ideally, the scope of the present invention is related to an apparatus comprising sensing elements that can be used to monitor within the harsh environment, in particular the wet environment.

One of the primary applications of the apparatus in accordance with the present invention is the precision agriculture in particular for aquaculture and horticulture.

With regards to the current applications of chemical sensors relative to the precision agriculture and environmental monitoring, it would be a great advantage for users to obtain the following packaging attributes; which can be effectively provided by the present invention; said requirements are:

1. The sensing element to be exposed to the respective environment such as water and soil and yet the electronic components that implement the signal processing and signal transmissions functions is required to be enclosed and protected from the said environments;

2. The incorporation of advantageous redundancy in the number of sensors so that in the event that one sensor is spoiled or damaged, or contaminated by dirt, the other sensors can still proceed with data collection and thus support the functionality of the spoiled sensor; 3. The packaging of the present invention allows the sensor apparatus to be movable devoid of damage, particularly when placed in water with current movement;

4. In the event that the sensor apparatus of the present invention is deployed within water environment, i.e. paddy field, pond, wet blend soil and sludge pool, the packaging is able to be partly submerged in water in order to allow vast portion of the sensors exposed to the liquid or any sort of water environment as aforementioned .

Ultimately, the technology of the present invention allows multiple sensors which are MEMS based; of the similar types and/or different types being accommodated within the robust packaging; and allows wireless monitoring of sample and wireless data transmission upon collected via the said sensors to the World Wide Web based central unit for processing and further analysis. The components which are housed within the packaging allow data to be collected and subsequently provide and/or communicate to the web based unit in an efficient and timely manner compared to the existing prior arts.

It is further noted that the sensors or sensing elements (8) contained therein may take on a wide variety of purposes, including but not limiting for pH measurements, chemical ions, temperature, detecting electrical, physical, chemical and/or biological property associated with said sample.

As accordingly shown in Figure 1, the preferred embodiments of the present invention comprises a plurality of wireless card and mini antenna (2, 2a) for receiving and transmission of wireless data, a plurality of on-chip analog and digital signal processing means (DSP) (4, 4a), a plurality of read -out input circuit

(ROIC) (6, 6a) and a plurality of sensing elements (8) for providing a plurality of measurement types . In accordance to one of the preferred embodiment of the present invention, there is provided at least a pair for each of the aforementioned components in order to achieve the desired outcome when employed.

It is understood by a person skilled in the art that the components as aforementioned if taken alone are conventional components which are typically used in the relevant art for various applications.

The first component is a wireless card for use in the apparatus of the present invention functions primarily to facilitate in transmitting as well as receiving data to and from a gateway. In order to achieve this function, it is coupled with an antenna so as to enable the said transaction of data through microwaves. The second component is the on-chip analog and digital signal processing means (DSP) (4, 4a) which functions primarily to process the signal received from the sensing element (8) .

The third component is the read out input circuit (ROIC) (6,6a), whereby its primary function having regard to the invention is to facilitate the DSP means for converting the input obtained from the sensing element to the required output signal, typically to analog output.

The aforementioned components are positioned or arranged within a housing means said housing may be in various shapes, whereby the said shape is adapted to accommodate the components as mentioned in the preceding paragraph. Accordingly, there are two housing means provided for this invention; whereby the first housing means (1) for accommodating at least one or a plurality of sensing elements (8) , and the second housing means (3) for accommodating at least one or the increased quantities of the micro electrical components, which are the mini antenna (2, 2a) , the DSP (4, 4a) and the ROIC (6, 6a) .

In accordance to a preferred embodiment of the present invention, the first housing (1) is in the form of a cylindrical body formed from a suitable material having a predetermined dimension, whilst the second housing (3) is in the form of two circular or disc shaped members having a greater diameter than that of the first housing (1) . The said circular members of the second housing (3) are attached on both ends of the cylindrical body therefore acting as lateral disc -like housings (3) .

In order to secure the sensing element (8) to the first housing (1), there is provided an aperture for each sensing element (8), said aperture having a dimension such that it is able to receive at least one end of the sensing element (8) which is fixed thereto as shown in Figure 1. It is further noted that apart from the above securing method, the sensing element (8) may be removably secured to the first housing (1) by way of a suitable fixture or fastening means. Further description on the attaching the sensing element (8) in accordance with the embodiments of the present invention will be described shortly herein.

It is noted that the first housing (1) and second housing (3) are adapted to be attached to each other by suitable fastening means and can be accordingly dismantled in order to incorporate the main components of the present invention. For use of this invention, both of the first (1) and second housing (3) are formed from a suitable material known in the art which allows the apparatus of the present invention to float below the water surface or at least does not sink to the bottom of the sample when deployed in water influenced environment. In one embodiment of the present invention, the sensing element (8) is accordingly positioned within the first housing (1) in such a manner that the sensing end is exposed externally from the said first housing (1) . In this position, the sensing element (8) can be sufficiently in contact with the sample during use. In this position, at least one end of the said sensing element (8) is inserted into the aperture provided by the first housing (1) and thus fixed thereto. Alternatively, the sensing element (8) can be fixed to within the first housing (1) with suitable fastening means.

As briefly mentioned in the preceding paragraphs, the micro electrical components are generally positioned within each lateral members of second housing (3) as shown in Figure 1 by way of suitable fastening means. The said components are accordingly secured and protected by said second housings (3) from any environmental influenced damages . The said components are in communication with each other during operation in order to deliver results to the network. There may be provided data storage means; i.e. a memory card within the interconnection of the said components in order to store data prior to being sent to the World Wide Web based network for further analysis.

In another embodiment of the present invention, there may be provided a plurality of sensing elements (8) , and a plurality of wireless card and antenna (2,2a), a plurality of on chip analog and DSP (4,4a) and a plurality of ROIC (6, 6a) whereby the sensors (8) in accordance with the present invention are accommodated and thus arranged within the cylindrical body of the first housing (1) whereby the said sensors (8) are accordingly arranged within a predetermined distance in relation to each other. In this arrangement, each of the plurality of sensing elements (8) are positioned in a manner such that the sensing end of said sensing elements (8) are extended externally from the said cylindrical body of said first housing (1) at a predetermined length leaving the sensing end of the sensing element (8) exposed and thus it is allowed to be sufficiently in contact with the sample or measurand.

In order to achieve the above position, at least one end of the said sensing elements (8) are inserted into the plurality of apertures provided by the first housing (1) and thus fixed thereto. Alternatively, the sensing elements (8) can be fixed to within the first housing (1) with suitable fastening means.

In this embodiment, the plurality of micro electrical components are accordingly fixed within the second housing (3) as seen in Figure 1, whereby the circular lateral member of second housing (3) can accommodate at least set of the said components. In the event that the apparatus of the present invention is used in water or liquid influenced sample as shown in Figure 2, the first housing (1) and the second housing (3) is accordingly submerged and allowed to float below the water or liquid surface whereby uninterrupted pollutant reading can be achieved.

In effect, the apparatus is positioned such that the sensing elements (8) are in contact with the sample. Upon collected the desired signals from the sample or measurand, the means for processing wireless signals from said sensing elements (8) therefore wirelessly transmits and/or communicates data to a gateway for further processing and analysis. It is noted that the processing unit in accordance to another preferred embodiment of the present invention is in the form of, but not limiting to a world wide web or any form of gateway.

It would be appreciated that the amount of sensors or sensing elements (8) can be increased subject to the dimension of the first housing (1) as the increased number of sensors or sensing elements (8) allows enhancement in regards to the accuracy and the sensitivity of the detection and even though one of the plurality of sensing elements (8) is damaged or contaminated, other devices and sensing element (8) can still proceed with providing detection as desired. It is therefore understood from the embodiments of the apparatus of the present invention allows the plurality of sensing elements (8) for detection, whilst the signal processing components which comprise of analog and digital processing and wireless cards are enclosed (air and water protected) suitably within the said apparatus .

Although the present invention has been described with reference to the preferred embodiment thereof, it is apparent to those skilled in the art that a variety of modifications and changes may be made without departing from the scope of the present invention which is intended to be defined by the appended claims.

Claims

1. An apparatus for wireless sensing for use in measuring and monitoring a sample; said apparatus comprising :

a first housing means (1) for accommodating at least one sensing element (8) ; a second housing means (3) attached to the first housing means (1) for accommodating and encloses a means for processing signals (4,6) from the sensing element (8) and generating an output; and a means for transmitting (2) said output from said means for processing signals to a gateway; wherein the sensing element (8) is positioned within the first housing (1) such that at least one end of the said sensing element (8) is secured to the first housing (1) and another end can be in contact with the sample.

2. An apparatus as claimed in Claim 1 wherein there is a plurality of sensing elements.

3. An apparatus as claimed in Claim 1 for use in harsh environment, said harsh environment is preferably liquid and/or water environment.

4. An apparatus as claimed in Claim 1 wherein the means for processing signals from said sensing elements (8) and generating an output includes an analog and digital processing means (DSP) (4, 4a) for converting the data from sensing element (8) to a digital data; and a read out input circuit (ROIC) (6, 6a) .

5. An apparatus as claimed in Claim 1 wherein the means for transmitting the output from the means for processing signals to a gateway includes an antenna and a wireless card (2, 2a) .

6. An apparatus as claimed in Claim 1 wherein the signals from the sensing elements (8) are wireless signals.

7. An apparatus as claimed in Claim 1 wherein the said output from said means for processing signals is transmitted wirelessly to a gateway.

8. An apparatus as claimed in Claim 1 wherein the sensing element (8) is anyone of electrical, physical, chemical

' and/or biological sensing elements, in which the selection of the sensing element (8) is dependant on the properties to be tested on said sample.

9. An apparatus as claimed in Claim 1, wherein during use in liquid or water environment, the apparatus is submerge and allowed to float below the water or liquid surface and therefore the sensing elements are in contact with the water or liquid sample devoid of interruption.

10. An apparatus as claimed in Claim 1 wherein the first housing (1) is in the form of a cylindrical body having an aperture for securing the sensing element (8) to said first housing (1), wherein at least one end of the sensing element (8) is inserted accordingly into said aperture .

11. An apparatus as claimed in Claim 1 wherein the second housing (3) is in the form of two lateral members with circular cross section attached to each end of the cylindrical body.

12. An apparatus as claimed in Claim 1 wherein the first housing (1) is attached to the second housing (3) by way of suitable fastening means, and can be detached and dismantled so as to incorporate any related components.

13. An apparatus as claimed in Claim 1 to 12 wherein the apparatus is self buoyant when deployed during use in water influenced sample.

14. An apparatus as claimed in Claim 1 to 13 wherein if a plurality of sensing elements (8) is deployed and in the event that of one or more of said plurality of sensing elements (8) is damaged or contaminated, other means and sensing elements can still proceed with providing detection as desired.

15. A method for measuring and monitoring a sample comprising the steps of:

preparing an apparatus as claimed in Claim 1;

detecting electrical, physical, chemical and/or biological properties associated with the sample;

convert data from detection to a digital signal; and

wirelessly transmitting digital data to a gateway.