 Next, I would like to invite the open PLC group under the mentorship of Rajesh sir to proceed with their presentation. Hello and good afternoon everyone. Myself Alankrita and she is my friend Mansa. During this two crucial months of our internship we have worked on a project called open source PLC. Well, as soon as the word PLC comes to our mind the very thing which strikes my mind immediately is automation. Now, what is the need for automation? I am going to show you with a very simple example. We are coming to our room and we are turning on the lights and they are glowing and switching on the fans and it's moving. So, I think it's really comfortable for us to fill. But what will you fill if you are asked to turn it on and off after every 30 seconds interval? Will it be good? I don't think so. Actually we will appreciate it. It will be so irritating. Now think about the situation. If in industries the experiments like bottle filling and all these are to be conducted manually then it will be so much hectic. I think industries are going to be handicapped without automation nowadays. Next slide please. What is basically a PLC? A programmable logic controller is a device that automates machinery in factories and workplaces. It's a more generic and robust version of the well-known microcontrollers in use. That is basically what is a PLC. But believe me, before coming here I just heard about PLC but I could never think of something called open source PLC. Now, after working here for two months, I can believe that something as simple and as dynamic as a simple microcontroller based PLC is possible. And depending upon that also we can implement experiments and large scale experiments like elevator, car parking, everything. So that I could understand after working here for two months only. Otherwise it would be quite impossible for me to understand that something as simple and as dynamic as an open source PLC based on a simple ATMAGA 16 microcontroller that we have built is possible. And as you can see here we have the prototype also. We'll be showing the simple demos also just at the last part of our presentation. So before that I would like to hand over the mic to my teammate Mansa. She will explain all the technical details, what are the challenges we have faced and all these things and what are the solutions we came up with. She will elaborate all the things over two months. Good evening everyone. I hope all of you are interested. Okay, so before going to the technical details, I know that you all are very well versed with the idea of open source, right? So I'd like you to know that there's something called open source hardware also there along with your open source software which you all heard of, right? So the first question that comes over to you is why would you actually need an open source version for a PLC, right? So basically the main concern was these ITI colleges and the polytechnic ones don't basically have this PLC setup. These PLC setups are really huge and they control devices that run on really high voltages like around 230 volts or probably any kind of voltages. So the main problem is this is actually a subject which is taught, okay? But the students don't really have a setup to work on. They really learn just the theory and nothing else. But you would have all heard of this fact that you will always understand better if you do it practically rather than doing it on just a screen or learning it all by yourself, right? So what was the idea for an open source hardware implementation for this? Okay, so how we went about doing the project was such. Firstly, we had to come up with a controller which supported a lot of IOs. This was because probably if you have a huge setup, you would want a lot more number of IOs than you would think of. Then we had to think about the flashing method that is putting the hex file onto the code. Thinking about that, the ISPs that are the in-system programmers, I won't go into the details but I won't bore you off with the technical aspects. But yeah, there were a lot many ideas for that. So we had to stick to the idea which was the best one and the cheapest one so that it can be incorporated into a very small budget. And yes, the mechanical setups were a major task involved in this. We had to show the implementation in the real time. Alright, so yeah, the major task was to understand the IC and how we would be programming it. So you guys are very well versed with the terminals that you use on Linux, right? So we use the same terminal and there's this thing called AVR Doot. Don't laugh on the name but this is the thing which is used to flash your AVRs or pick controllers. So this is our first prototype that we built. We would proudly call it version 1.0. Okay, you can see those two DB9 connectors there. One is for the UART and the other one is for programming. Over there, the black thing, the straight one, that's again for programming it faster. Then you can see the IC there, that's AdMega16AIC, that's Max232 for the UART. And that's the power supply. Okay, so for the software part, we actually came across this software called LDMicro which easily incorporates these ladders which are used to understand, which is basically one of the logics which is used to a program of PLC. It's more or less like the digital logics that you all might have heard of, right? There are a lot more logics that are incorporated but LDMicro supports ladder logic, which is easy to understand. So we stuck to that. And the best part in LDMicro is it generates the hex file directly. So you need not do a manual intervention in between. You just compile it and you get a hex file for that. All right. So coming to the challenges faced, basically there's a very little amount of documentation or something very substantial to think about when it comes to programming using this terminal thing that I told you right now that's called AVR Dood. So we couldn't basically find a lot of documentation on that. So we had to spend a lot of time understanding how that IC would respond to that commands written on the terminal. So basically what we wanted was such a screen. All right. You can see those loading things and all that. But what we always got was such a thing. Device not responding and all that. So it was very, you know, disappointing and hard for us to digest the fact that we did so much work and it's not working, it's not working. But finally when you see that screen which I showed you, you feel really happy that it's working finally. Oh yeah. Coming to the cost and the feasibility of the project that we, the board that we made, we actually designed the whole board using some help also as in we had to come across all these ISPs also and select the best one as I told you earlier. So when we calculated the cost, it came out to be exactly to be precise. It was 380 rupees. So I would say less than 400 rupees for that. That is a much larger improvement over a PLC which would cost about 15,000 rupees. So these polytechnic colleges which I talked about can easily incorporate such a development board. But you would again ask me what's the difference between an Arduino and say this, right? Arduino firstly has lesser IOs. Secondly, Arduino is a more of a microcontroller aspect of this thing. This thing that we made has relay circuits and other things which can be used for these setups which require PLCs. Arduino can be used, yes of course. But you would know that an Arduino would cost about 1,500 rupees if I'm not wrong and our whole setup would come in that much. So I guess if you have something which is as good as that an Arduino basically and you can buy a setup within that much amount I think I would be really happy with that, right? So yeah, the one which we made right now has about 12 plus experiments and I told you 1,500 rupees is the cost. So I guess like if the project that we've incorporated in this are basically the ones that are really essential and required to understand a PLC. So we've tried to incorporate whatever's there. You have a UART function also. Say you want it, you can incorporate that also. Next comes LD MicroAnnet interface. As I already explained, it's a really easy interface. You can really get through it. It's like a cakewalk basically. It's really easy to understand. And yeah, it helps us also. It generates the experts so we needn't worry so much. And yes, while we were doing it, we went about documenting it really properly. This was because when we were doing it, we found it really difficult to actually understand all the concepts. So we were like, if we are going to give it to someone, we better document it properly so that it doesn't become a lot of trouble for someone else to understand that. Okay, again the challenges that we faced. As I told you, at Mega 16, no proper programming ideas are present online. Then phishing up the best solution, the cheapest one. Then incorporating the major functions that are required. Then protection circuits. Obviously protection circuits are really necessary because if you say short or you invert the terminals, you might end up frying up your controller. You would not want to do that. Then designing the board and the policies. So these were the technical aspects. Then mechanical issues. We basically, before starting this, we just worked with the motors without the tension and that conveyor belt. We found, okay, this is really simple. But that setup itself took days together. And trust me, we took two days to figure out what is going wrong and what's not right. So yes, mechanical issues are always there. And yes, technical issues, obviously, we had to do this thing called fuse setting, which is actually done to change the way a controller behaves. So if you do something wrong in that, you might end up losing your controller. It will never respond until and unless you provide such a thing. So we ended up losing three of our lovely controllers in that way. And yeah, these are the photos of the setups that we did. And we would want to proceed with the demo. Thank you all. Yeah, we'll proceed with the demo. It's making some noise. I'm sorry for that. But let it be. I hope it works. So this is our setup for an elevator system. So I don't know if you guys can see it, but there's something like this over here which would move. I hope it works. So if I press this button, you can see, this is like a person standing outside the lift. And these black tiny things that you can see are called limit switches. Now I pressed from outside that I want the lift to come here. So the lift came here. Now say I press, I get inside the lift. I press this G. You can see this G. So I press this. It will go back to ground floor. If you would have come across this whole thing wrong with the setup, this always happens when we are doing some demo, right? It would never work when there's a demo. All right, it worked. This always happens. Everything will work perfectly fine. But the time of demo, that thing has to make noise. Everything has not got to work. All right, it's okay. I just wanted to give you a brief idea about it. So now say I press this. I hope it works. All right. Say I press two. Yes. Okay. So this was a small demo about the elevator system. So we have another setup which is basically a control loop. Okay. Basically there's a bulb. You guys want to see it? Cool. Would you guys mind waiting for two minutes? We need to just remove these setups and then do the wiring and all. So there's this bulb which heats up. There's a thermistor attached to it. I need to flash it, but I will flash it with a program which basically starts the fan once there's a temperature rise. It will maintain it within some temperature range. So wait for a second. All you guys are okay with the video which I took earlier. Okay. So you can see that bulb right there. There's this small black thing over there. That's the thermistor. So the bulb has turned on. Now it turned off. The fan has turned on. Yes. I'll do that in a while. Yes. So basically what we are trying to do is you guys might not have come across this, but it is something like a self-sustaining system. Basically what we are doing is this bulb heats up. There's a thermistor. A thermistor is like a resistor which changes its value over the rising temperature or a fall. So basically a thermistor is used to detect the variation in the temperature. Once the threshold is reached, we would... Once the threshold is reached, we would want the bulb to turn off and the fan to turn on so that we maintain the temperature at the same level. So this is something which is a self-sustaining system. Obviously you don't need a person to stand there and touch it or something. It's a self-automated system which you would probably see when you're working with PLCs. The other setup that we had done was a simple RG... I mean this traffic light thing. It's a simple thing, but yes. I mean to understand the concept, even such a small thing has the concept of counters and timers in it. So it helps you to understand the basics. This is a car parking system that we have. So basically when a car comes across the rail, the shaft gets up and then in some time it comes down. This is done using a stepper motor. So basically we did that. You can have the concept of limit switches and you know automation in that again. After this is done, yeah, I guess we are done with that. This is the same lifting that you saw. I press 2, it will go to floor 2. Now if I give a manual input over there, it comes to that door. Then you go inside, you press any button, yeah, ground. It goes down. You request it to come. It comes to the second door. You won't believe the ladder for this was around 20 rungs which was the maximum size of our code in this. The whole setup, the maximum amount of code was for this. I mean you can extend it to any other idea which you want. That's why we had 12 plus experiments. You can do it for two floors. You can do it for one floor. You can do it for a conveyor system also. So we have all those things incorporated in that. So I'd like to end it by thanking Karnan sir and Kozla sir. Firstly for Gling is the idea and the path to go across the project in itself. Then we would like to thank Rajesh sir for helping us, especially with the mechanical setup and all the other requirements. Then I'd like to thank my mentors, Niveditha ma'am and Akshay sir for constantly supporting us and helping us out of the project. Thank you so much.