Lesson 1 - NEMS in the Automotive industry

This lesson activities aim to teach students about the NEM sensors utilization in the automotive industry. Furthermore, students learn about the involved sensors’ structure, characteristics and behaviours in nanoscale dimensions.  

This lesson is dedicated to Junior Secondary School students (K11-K13). Students at Junior Secondary School have already been taught about speed and acceleration notions. 

The objectives of this activity are grouped to demonstrate NEMs sensors and the computational Thinking techniques in a problem-solving procedure. Namely, students are encouraged to design a NEM gas sensor following abstraction, decomposition and pattern recognition. 

60′

Learning Activities

Act.1 - Introduction about NEMS in the Automotive industry

This is an introduction to how NEMs are used in the automotive industry. NEMS pressure and flow sensors, accelerometer sensors, gyroscopic, and inclinometers use NEMS technology on a wide scale in the automobile industry.
As an application NEMS pressure is widely used as integrated into the tires of vehicles to measure and monitor the pressure continues, it detects unsafe underinflated conditions more accurately by sensing time-to-time pressure and transmitting tire pressure information to the screen through a radio frequency signals. At a certain pre-determined point exceeding it warns the driver about the condition. This will ensure the safety of both vehicles and passengers while helping to extend the durability of the tire life span.

Act.2 - How to use NEMS Devices for Passenger Safety Purposes?

The next session explains how passengers are benefited by the NEMs utilization. The NEMS pressure sensors integrated with accelerometer sensors are designed in the airbag firing systems to detect sudden declarations more accurately to fire the airbag.

Compared to installing met of G switches this makes less cost and less weight to the vehicle is also an added advantage. In modern vehicles, there are side airbags installed in vehicle doors, and the airbag firing system is activated by sudden pressure difference which causes deforming the side door. This is calculated by MEMS pressure sensors to fire upside airbag systems.

Conventional G switches

Conventional G switches of airbag sensing carry more disadvantages by being less sensitive as well as high cost. 

The next pictures show the way an old-fashioned conventional G switch sensor operates. It is almost obvious the delay on its reaction.  

Act.3 - Exhaust Gas Recirculation System

Vehicle exhaust gas recalculating systems are increasingly using NEMS pressure sensors. Nitric oxide, a harmful gas created during combustion, is released less frequently when it is recirculated into the combustion engine. As a result, the recirculation system’s valve at the combustion exit is managed by NEMS pressure sensors. High exhaust gas emissions can be detected by pressure sensors at the combustion engine’s exit, which permits the recalculation valve to open wider and allow for more recirculation back to the combustion engine.

Act.4 - Design a NEM sensor for gas detection

The next picture depicts a NEM gas sensor designed with the Tinkercad platform. Resonating at MHz frequencies, even without optimisation, the sensor has shown a remarkable mass sensitivity of 11 zg/Hz (z = zepto = 10E-21).

This activity is about the design of the above sensor by using the Tinkercad. Students and/or teachers are asked to complete the next picture schema activity design, export the result to .stl format and subsequently print this to a 3D printer. Furthermore, the activity is not only to develop design skills for students, but is to teach how they can apply the Computational Thinking skills to solve a problem (aka design a NEM sensor).

Let’s see how it works!

NEM

Download the .stl file

Act. 4.1 - Applying Computational Thinking techniques

Computational Thinking (CT) is undoubtedly considered a fundamental skill as reading, writing, and arithmetic in the 21st century. Janette Wing expressed that CT refers to the mental processes involved in formulating a problem and expressing its solution(s) in such a way that a computer—human or machine—can carry out the task effectively. Currently, CT has become commonly accepted as a problem-solving method which includes a set of concepts such as abstraction, decomposition, generalization, algorithmic thinking and evaluation. 

Below, we demonstrate the way of applying CT techniques for the process of sensor design.

Step 1 - Abstraction
Step 2 - Decomposition
Step 3 - Pattern Recognition

Students are encouraged to analyze the initial challenge and keep only the essential elements as key elements to design the sensor. Students leave apart of all unnecessary information.  Thus, according to gas sensor specifications, they keep only the next picture semantics.

The next step is to decompose the initial problem into smaller manageable parts. This makes the complex problem of designing a NEM sensor more approachable by breaking it down into individual components that can be solved sequentially or in parallel

The last step is to find out any similarities and specify patterns. Patterns help students to better understand the structure and the functionality of the sensor. 

Abstraction

Practice

Assessment

  1. ineffectively tries to notionally separate the initial problem
  2. formulates a partly acceptable decomposed problem solution
  3. formulates a series of individual subproblems which are part of the initial problem
  4. designs solvable individual subproblems which results in the initial problem solution

CT Concepts: DE, AL, AB

  1. can not identify similarities and/or differences in a problem solution
  2. identifies some of the similarities and/or differences in a problem solution
  3. can tranform the similarities to patterns
  4. successfully applies the recognized patterns to the final problem solution

CT Concepts: GE, AL

  1. inadequately designs artefacts
  2. designs adequate artefacts but faces difficulties in the implementation phase
  3. creates “weak” digital artefacts (lack of stability, trustworthless, not tested, etc)
  4. creates solid digital artefacts, effective and well-designed

CT Concepts: AL, AB

  1. has no clear image of a procedure usage
  2. Knows that a procedure can be used to hide the detail with subsolution
  3. inadequately uses the procedures in a program solution (still needs improvement)
  4. perfectly designs, writes and debugs programs using procedures

CT Concepts: AL, DE, AB, GE

  1. can not recognize the role of accurate data in a problem’s solution
  2. partly effectively uses the notions of data and information
  3. can collect, organize, store data, and evaluate the resulting information
  4. evaluates the received feedback and improves the offered solution

CT Concept: EV

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