 Let me first make an introduction of both sides. So, this is a regular undergraduate third year class that I teach in this slot right. They happen to be a third year students of the department of mechanical engineering and we teach them a course on electronics. To the third year students of this class, we have several teachers, several professors from other universities here and they are trying to see how a class is conducted, how we carry out assignments and presentations at IIT Bombay. And the objective of this session is to introduce the idea of student participation and student presentation and to give a feel of that as we have at IIT Bombay right. Let me give a brief background to the theme that we are going to look at today. You see these students have been given an assignment pertaining to exploring applications of electronics in their field. So, you see the whole objective here is that teaching has two components in it. I mean one part is what you call formal instruction that we see all the time I am sure professors from other universities have a lot of exposure to that dimension of teaching. There is another dimension which we call cooperative learning which formally is called cooperative learning that relates to bringing students together to do some self exploration. You know incidentally if one looks at the word education, it comes from two roads Latin roads X and Dukare which really means to bring out X means outwards look it really means to bring out I mean in short. So, if and even if one looks at the way you know education is described either in the ancient western system or in the ancient Indian system there is an emphasis on recognizing that there is potential within the student and letting it flower. So, very seldom does one think of education I mean the great masters in education or in teaching have always regarded education as a process of letting a plant bloom something similar. So, you know you when you want a plant to grow you do not paste leaves on it you water it you give it sunshine you give it in the soil in which it can flourish and the plant grows from a seed. So, it is within it comes without that is education. Now, the same thing holds for that is a part of education. You see of course, when you want to grow a plant there is always this requirement that you at times need to prune at times you need to specifically grow some parts or encourage some specific stems to grow and so on to nurture. So, nurture is an important part of education nurturing the talent within. So, although formal instruction is a very important part of education the dimension of nourishment of nurturing of allowing sunshine in which the potential within can come without is a very important part of education. And very often assignments given to a class or opportunities given to the student community to carry out relatively open ended projects are a step in that direction. So, let me introduce the specific theme that we have today. Well these students were asked to explore the applications of electronics and electrical engineering in mechanical engineering. Their basic discipline is mechanical engineering and they were asked to explore the applications of electronics and electrical engineering in mechanical engineering either directly or indirectly. I mean does not have to specifically relate to a device in mechanical engineering, but it could relate to ideas that are useful in mechanical engineering or it could relate to what mechanical engineers need to use that was the theme behind it. And what we have done today is to select a few groups who have come well prepared with a presentation to talk about what they have surveyed, researched and presented here. We will first have them present and then afterwards we will discuss some of the aspects of the presentation, some of the finer points and so on right. So, I will first invite the group take their presentation. The respected teachers and my dear friends, myself Rohit Vadeva, my friends are Aditya Katte and K. N. B. Teja. So, here we have done a presentation about anti-lock braking system for this course. And as you might be aware this anti-lock braking system is a mechatronic complication in which the motor vehicles, steerability as well as the stability control. These are to be required to be controlled. So, the basic purpose of the ABS is to maintain the stability and controllability of the overall steering system. And the main aspect of this is that whenever this controllability of the car discovers that either of the particular wheel under consideration is moving very slow, considering its translation velocity is very low compared to other wheels. So, in such cases the system stops such wheels, stops uplink brake on that wheel so that it regains its speed and the overall translation velocity is same for each individual wheel. So, it helps in maintaining the constant speed. So, as we are shown in the next diagram, this is a basic scheme of the system. As you might see over there that there are 4 wheels we are shown. Each wheel is connected to one sensor and there are 4 control walls each for one wheel and there is one electronic control unit. And there is also one pump and a master cylinder which controls all the fluid. So, now my friend will take over and explain you a bit more about this mechanical parts first and then we will carry over to electronics. The master cylinder converts the force applied by the brake booster and the pedal into hydraulic pressure of the brake fluid. And the brake booster basically increases the force applied by the pedal and brake fluid it is used to apply the pressure and it is designed to operate at high temperatures. It has low melting point and high boiling point. And control valve is used to control the amount of fluid flowing to the brakes it acts as the valve and it is controlled by the electronic control unit and fluid reservoir stores the working fluid which is the brake fluid. Then pump and here we use the pulse width modulated pump and it acts as the pressure booster basically increases the pressure of the brake fluid. Then vehicle speed sensor it is made up of toothed disc and it is mounted on a shaft and also there is a magnetic coil and stationary detector is mounted on the magnetic coil. The detector sends electrical pulses to the computer and these are generated through the magnet and as the vehicle speed increases the frequency of the pulses also increases. This is the typical circuit diagram of the antelope braking system. These orange ones are the sensor attached to front wheel and these are sensor attached to rear wheel. This IC LM2901 are sensor conditioning comparators which compare the inputs output of the sensors and give the order output to this CPU microcontroller blue one which IC number is HPC16083. Then the green one is the voltage regulator. It is a low drop out voltage regulator with a delayed reset and the delayed reset is given by a delayed capacitor. This LM1956 is a solenoid driver smart power and the three ICs which are in the bottom of the circuit are used basically for the failsafe purpose. This is another compressor microcontroller COP8640 and the ICs LM1921 and 1951 are used for lamp drivers and relay drivers respectively. The basic function of CPU microcontroller HPC16083 is the main driver of this whole antelope braking system. It has a multi-plan divide instruction cycle time of 7 milliseconds. Then it provides the necessary input capture registers and PMW timers to drive the four wheel and four channel antelope braking system. We are not going into pretty details of the circuit diagram of the compressor microcontroller but the basic function of the compressor microcontroller is to dealing with the fault tolerance and diagnostics. Now sensor conditioning comparators, these are the comparators which compare the sensor outputs given by each rear wheel and front wheel and the good feature of this is that they can be driven from a single power supply and a split power supply can also be used for driving them. Another IC is voltage regulator which was connected battery, unregulated battery input is given to this voltage regulator. It is a loaded up voltage regulator with a delayed reset and that delayed reset is given by the delay capacitor which is as shown in the pin four of the circuit diagram. The another safety component, lamb driver high side switch LM1921 is the uses PNP transistor as a main driving component. Then the good thing with this is it has a very large range of output voltage so that your system works safely for most of the cases but in case of any failure the output can swing below the ground potential below 57 volts negative with respect to the power supply. These LM195 are relay drivers high side switch these are mainly used for the failure purposes. If there is some failure like open load or short circuit or thermal breakdown or currently if the circuit current limit increases or voltage or there is over voltage then as shown in this output four is error flag it sends error flag output back to the compressor microcontroller and it can then process the necessary so that the system works properly. The conclusion is that this antelope breaking system is a very user friendly active safety device and other the vehicles which are not having ABS present in them have to pump their brakes manually. When the ABS system is applied to the vehicle then this is automatically pumping the brakes out and the main precaution to be taken by driver is that to apply continuous force on the brake pedal so that the ABS system works properly. Let me mention about the references we have taken the IC diagrams and PIN configuration diagrams from National Semiconductor's website and the we have taken the help of the myseworks.com for the simulation purpose. That's all with the presentation. Thank you. That was a very nice presentation from the first group. Now we'll make some observations about the presentation and of course definitely some positive things. I mean I could see that the students have made a very good study a very good survey of the problem. They have explained the context in which this breaking system is important. They have been able to highlight both the mechanical and the electronic importance of the application and they've also been able to show some results on simulation which explain the behavior of the control system as a function of time. So it's a very good presentation. Now let's see if we have any questions. So I think that's also part of the learning process. So you've listened to a presentation. Now the other colleagues in the class might have questions. So let's or you know even anybody else who's listened to the presentation might have questions. Now one one you know must mention one important virtue of a good presentation is the number of questions it generates. Right. I mean the more the curiosity that you arouse the more successful you should think your presentation has been. So anyway so you know let's are there any questions that you might want to put. All right. So that I think we could certainly have more questions. I see there are more questions but let's have another presentation now. Right. Now you have another presentation the breaking system. What I suggest you do is to come and only add to what has been said. Right. In a couple of minutes. Yeah the second present now they have a compliment to this or should we I think take the other let's see to be let's take the other ones first. Right. If you don't mind that we have different aspects explored. So now we have other teams also having been explored. So let's good morning everybody. We are going to have a presentation on a mechatronics product that's not been implemented in India till now and that's called the automated railway crossing system basically on the level crossings. Many of the level crossings out here in India are unmanned and that's a concern because as you can see there are so many there are so many unmanned railway crossing crossings out here. So many accidents happen and the number of accidents increasing is a matter of concern out here. So that's the reason why we chose this topic and that's the thing. What we are going to do is to present a concept that would we are going to present a concept that would help us to implement something that so that the doors automatically automatically gets closed whenever we whenever a train approaches the crossing. So that's a basic working principle. We'll sense the train approaching. We'll use the same signal as the input out here. I need to make a point. The signal we are using is the train signal. The trains have red and green light out there for the train motion. As soon as it's green it would go otherwise it's obvious. So what we are going to do is as soon as the light turns red or green we are going to sense that signal and we are going to input the signal to the DC, we are going to use this input to drive a DC motor using an edge bridge. It's cost effective because all the components are transistors and all that are really are very cheap as compared to the other things what we would be presenting and it's safer because there are zero chances of human error and it can be controlled straight away from where the signals are controlled. So that's it. That was a very good presentation. You noticed that the students actually explained the working mechanism. You know they related the components that had studied transistors, MOSFETs and so on. They related those components to a specific practical requirement of wanting to you know drive a motor in one direction or the other and they also therefore there is an electromechanical aspect to it. It's a very interesting presentation. We can take maybe one question. So what I would particularly like the participants of the course to pay attention to and of course the class as well is not only the question but how questions get generated right in the mind of an audience.