《现代传感器》课件Lecture2

Modern Sensors Lecture 2
X. Wu
Department of Optical Engineering
Zhejiang University
Lecture 2 Basic Intent
Overview the basic sensor terminology in product data sheets, and in the technical literature.
Department of Optical Engineering
Zhejiang University
Basic facts : R&D of modern sensors
Some of the people working in this business have great resources at their disposal.
a thermocouple, a photodiode, piezoelectric sensor.
Active sensor
The active sensors sometimes are called parametric because their own properties change in response to an external effect and these properties can be subsequently converted into electric signals.
So, expect that you will encounter odd definitions here and there, and expect that you will find that most sensor data sheets are missing some information that you might be most interested in.
Many researchers out there competing to invent, design, build and sell sensors which are going to next big wave in industry
This competition has been going on for decades What are the basic facts at work?
For a virtual reality game glove, it is better to have both.
Department of Optical Engineering
Zhejiang University
Introduction to sensor terminology
Why do we care so much about this interface?
Department of Optical Engineering
Zhejiang University
Data Sheet: Purpose and
The data sheet
Format
is primarily a marketing document.
It will be designed to highlight the positive attributes of the sensor, emphasizing some of the potential uses of the sensor,
Researchers at l labs, where access to state of the art materials and equipment is key to finding the next really important sensor.
Department of Optical Engineering
Zhejiang University
Introduction to sensor
terminology
A sensor is a device
which converts a physical phenomena into an electrical signal.
As such, sensors represent part of the interface between the physical world and the world of electrical devices, such as computers.
The other part of this interface is represented by Actuators, which convert electrical signals into physical phenomena.
Department of Optical Engineering
Zhejiang University
Where do Sensors Come From?
We are going to cover a significant fraction of modern sensors,
some sort of invention Interesting to think how such things come to be
Case study: an off-the-shelf accelerometer, ADXL150.
Then, a summary of the basic electronic circuits we will be covering in the course is presented.
The data sheets for many sensors are formatted just like electronic product data sheets.
However, there are many formats out there, and nothing at all like an international standard for sensor specifications.
Zhejiang University
Introduction to sensor
terminology
Characterization and data sheet
since the output of the sensor is an electrical signal, we tend to characterize sensors in the same way we characterize electronic devices.
We will encounter a variety of interpretations of sensor performance parameters, and sometimes a lot of confusion will emerge. It is important for you to realize that this confusion is not due to our inability to explain the meaning of the terms - it is a result of the fact that different parts of the sensor community have gotten comfortable using these terms differently.
In this case, the vendor and customer might have grown accustomed to unusual definitions for certain sensor performance parameters.
As a potential new user of such a sensor, it is initially your problem to recognize this situation, and interpret things reasonably.
Department of Optical Engineering
Zhejiang University
Sensor Classification
Passive sensor
does not need any additional energy source and directly generates an electric signal in response to an external stimulus;
For example, a thermistor is a temperature-sensitive resistor. These variations (presented in ohms) directly relate to temperature through a known function. a resistive strain gauge in which electrical resistance relates to a strain.
In recent years, versions of these products which utilize microprocessors for control of functionality are becoming widely available.
Department of Optical Engineering
Access to resources (people, equipment,…) is a big advantage.
Market Drive- an important driving power