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Smart sensors are sensors with integrated electronics that can do one or move following functions:- Logic functions, two-way communication, make decisions. It consists of transduction element, signal conditioning electronic and controller or processor that supports some intelligence in a single package. This paper introduces concept of smart sensors and controllers systematically. The progress in the integrated circuits become possible because of the tremendous progress in semiconductor technology, resulted in the low cost microprocessor. By designing a low cost sensor which is silicon based the overall cost of the control system can be reduced. The usefulness of silicon technology as a smart sensor, physical phenomena of conversion to electrical output using silicon sensors, characteristics of smart sensors. The silicon sensor can produce output, as voltage, current, resistance or capacitances, output format can be analog or digital. Suitable signal conditioning circuits along with processor can easily designed using silicon technology. The presence of controller or processor in smart sensor has lead to corrections for different undesirable sensor characteristics which include input offset and span variations, non-linearity and cross sensitivity. As these are carried in software, no additional hardware is required and thus calibration becomes an electronic process. Reduced cost of bulk cables and connectors, cost improvement and remote diagnostics are the qualities of smart sensors. In this paper specifically laser based smart displaced sensor is explained, how smart sensors help anesthesiologist in Anaesthesia supervision is elaborated. An effort is made to demonstrate a prototype Sensor system. "Smart dishwasher controller". Features of smart valve controller ends this paper.
Introduction (Smart Sensors)
Usefulness of silicon technology in smart sensor
General architecture of smart sensor
Importance and Adoption of smart sensor
Distributed smart sensor system
Application in Anaesthesia supervision
Smart Controller(Smart Dishwasher Controller)
Smart Valve Controller
1. INTRODUCTION: We can have integrated a sensor, which has electronics and the transduction element together on one silicon chip. This complete system can be called as system-on-chip .The main aim of integrating the electronics and the sensor is to make an intelligent sensor, which can be called as smart sensor. Smart sensors then have the ability to make some decision. Physically a smart sensor consists of transduction element, signal conditioning electronic and controller/processor that support some intelligence in a single package. Definition: -Smart sensors are sensors with integrated electronics that can perform one or more function, a) logic functions b) two-way communication c) make decisions.
2. USEFULNESS OF SILICON TECHNOLOGY IN SMART SENSOR: There are very convincing advantages of using silicon technology in the construction of smart sensor. All integrated circuits employ silicon technology. A smart sensor is made with the same technology as integrated circuits.
A smart sensor utilizes the transduction properties of
one class of materials and electronic properties of silicon (GaAs). A transduction element either includes thin metal films, zinc oxide and polymeric films. Integrating electronics circuits on the sensor chip makes it possible to have single chip solution. Integrated sensors provide significant advantages in terms of overall size and the ability to use small signals from the transduction element.
Different silicon sensors can be obtained by employing above effects. The silicon sensor can produce output as voltage, current, resistance or capacitance. Output format can be analog or digital. Suitable signal conditioning circuits along with processor can easily be designed using silicon technology. The presence of controller or processor in smart sensor has lead to corrections for different undesirable sensor characteristics, which include input, offset and span variations, on linearity and cross sensitivity. As these are carried out in software, no additional hardware is required and thus calibration becomes an electronic process.
Signal conversion effects:
Examples(Physical Effects in silicon)
Light Intensity, polarization
Photovoltaic-effect, photoelectric effect
Force, pressure, flow, vaccum
Temp, Temp. gradient
Concentration, pH, toxicity
Ion sensitive field effect
Field intensity, flux density
3. General Architecture of Smart Sensor: It is similar to a data acquisition system, the only difference being the presence of complete system on a single silicon chip. In addition to this it has on-chip offset and temperature compensation.
BLOCK LEVEL DESIGN CONSIDERATIONS FOR SMART SENSOR: - Design choice of smart sensor depends on the specific application for which the sensor is required and also related to specific industry.
4. Importance and Adoption of Smart Sensor: Following are qualities of smart sensor:
a) Reduced cost of bulk cables and connectors, b) Remote Diagnostics
4.1 Enhancement of Application:-
Smart sensor also enhances the following applications
a) Self calibration b) Computation c) Communication d) Multisensing.
4.2 System Reliability:
System reliability is significantly improved due to the utilization of smart sensors. One is due to the reduction in system wiring and second is the ability of the sensor to diagnose its own faults and their effect.
4.3 Improvement in Characteristics:
There is improvement in following characteristics:
Non-linearity, Cross-sensitivity, Offset, Parameter drift and component values.
4.4 Summary of Different Smart Sensors:
Some of the smart sensors developed at different research institutes are as follow:
Optical Sensor: -
Optical sensor is one of the examples of smart sensor, which are used for measuring exposure in cameras, optical angle encoders and optical arrays. Similar examples are load cells silicon based pressure sensors.
Accelerometer fabricated at the IBM Research laboratory at San Jose California, which consists of the sensing element and electronics on silicon. The accelerometer itself is a metal-coated SiO2 cantilever beam that is fabricated on silicon chip
Integrated multi-sensor chip developed at the electronics research Laboratory University of California. This chip contains MOS devices for signal conditioning with on chip sensor, a gas flow sensor, an infrared sensing array, a chemical reaction sensor, a cantilever beam, accelerometer, surface acoustic wave vapor sensor, a tactile sensor array and an infrared charge coupled device imager.
5. Distributed Smart Sensor System:
A distributed smart sensor system consists of a network backbone, on which reside many nodes. Nodes may be loosely classified as either sensor nodes or controller nodes. Sensor nodes are those, which tend to send data to the network, and controller nodes are those, which tend to gather data from the network.
A prototypical smart sensor node consists of three elements: a physical transducer, a network interface, and a processor/memory core. The transducer senses the physical quantity being measured and converts it into an electrical signal. Then the signal is fed to an A/D converter, and is now ready for use by the processor. The processor will perform some signal processing on the data, and depending on how it is programmed, may send the resulting information out to the network. Network transactions are handled by the network interface block. Note that these are only functional definitions and that MEMS technology potentially allows all three blocks to be implemented on a single die. A prototypical controller node consists of processor/memory, a network interface, and input/output devices for communicating with human users. It is used to collect information from the sensor nodes, to program the sensor nodes, and to provide feedback to the user. Placing all the sensors on a common network bus enables "plug and play" ease of installation. That is, no new wires have to be routed to accommodate new nodes.
Fig.No.5 Smart Sensor System Fig.No.6Prototype Smart Sensor Node
6. Specific Application Of Smart Sensor In Medical Field : The Anaesthesia Supervision: Actually, the essential difficulty of anaesthesia supervision results of the fact that, each characteristic signal (adequate ventilation of lungs, adequate circulation, and intra cranial pressure) is assessed separately. Consequently, it is difficult for the anesthesiologist to evaluate the patient's conditions. Moreover, he should able to distinguish equipment's dysfunction of a real variation of the patient state. So propose a new architecture for anaesthesia supervision, based on concept of smart sensor.
The Contribution of This System Are As Follows:-
1. The elaboration of a rate order from the trend curve of pressure measure and precedent rate.2. The supervision of the difference between the intracranial pressure and mean arterial pressure.
Validation data processing
Validated data bare
Rough Data Base
Elaborated Information and newservices
Central Supervision Unit
Communication medium of field bus type
Fig.No.7Central Data Processing Unit Fig.No.8.uture Architecture of Anaesthesia Supervision
7.Smart Controller: Smart controller is the latest inventory mode of controller.
Smart Dishwasher Controller:Current dishwashers enable the user to choose cycle selection, heat selection, and a start delay. Our Smart Controller will remove the cycle options by utilizing a turbidity sensor. The Smart Controller will interface with two modules: the control panel and the dishwasher hardware. Based on user inputs of heat and delay, the controller will send control signals to the proper dishwasher components. The addition of new sensors allows a more accurate pre-wash cycle that can rinse the dishes as long as necessary to remove the loose grit before starting the main cycle. This saves time, energy, and water--after all, even if the pre-wash cycle actually takes LONGER to run, the user will not have to rewash dishes!It will have inputs both from the user and from onboard sensors; the micro controller that will process the information and provide the appropriate instructions to operate the dishwasher; an amplification circuit to provide the correct signal voltage level to operate the various loads. With the use of a turbidity sensor and a microprocessor, we can take advantage of knowing that the dishes are clean. This will allow us to change the dishwasher operation from static cycles to dynamic cycles. This will undoubtedly result in more efficient wash cycles.
8. Smart Valve Controller:
Fig. No. 9 Smart Valve Controller
The Smart Valve Controller mounts to a valve solenoid quickly and easily- without screws, drills or additional wires. This rugged product is fully submersible and resists all moisture intrusion in water, mud and debris as deep as 12 feet. Operating off a single 9-volt battery that's guaranteed to provide power through a full season. It's also a breeze to program, with an easy to read and understand LCD display instead of cumbersome buttons and knobs. For isolated sites or power-restricted areas, and for the special needs of drip zones, the new Hunter Smart Valve Controller is your single-station solution.
9. CONCLUSION Smart sensors are becoming a considerable part of various fields such as industries, medical, defense. Silicon plays an important role in development of smart sensors. Still a lot of research is required to get benefits of smart sensors.
We recognize that Home Automation is the wave of future. "Smart Dishwasher controller" gives future vision of Automatic Smart control system. Smooth advantage of smart controller can be sensed by practical example of 'smart valve controller'.