 Hi guys. So this is what I made. This is how it looks like. You can go to Hutscape.com slash pine or even GitHub Hutscape slash pine to take a look at it. So the idea is what used to happen at night is because I have a baby now. We often wake up and turn on the aircon and then after 20 minutes still turn it off. So I was like, why can't I make a tiny little thing that will just turn it on and then after 20 minutes turn it off or also program it in a sense that we can keep it in another part of the room that is not near the aircon and if it is hot or cold based on that it can also turn it on and off. So that was the idea. So you can see it's really small here. This is the microcontroller here. This is the IR LED that kind of sends the signals to the aircon. It can potentially send to Roomba as well or any other IR device and this is the IR receiver that I record and capture. So in terms of IR blaster you can either have a dictionary of all kinds of IR code or you can record and capture it. So I went for the record and capturing. So maybe I can just show a very simple example. I guess I can go with Google Chrome. So when I log in and I guess I can't, am I sharing my screen? Yes, right? I don't know whether you guys can see my, can you see my, you can only see my Chrome is it? Yes. Yeah, we can only see your Chrome. Okay, I guess I can, I can share the entire desktop, right? Yeah. Okay. Can you see my entire desktop? Yeah, you see your terminal now? Yes, correct. So you see I have plugged in, can you see my face? I plugged in this via the USB and it has nothing there. So it tells me to go and configure. So let me try that. And this one also has web USB capability. So I can actually send message from here to my computer. And it will display on the browser. So I like to use web USB. So now you see Arduino zero, which is the microcontroller here. I will connect it. And I hope you can see what I'm doing. So let's say I will use my Aircon and I want to record the on button. So I'll say on what I'll do. I'll just simply point it here and notice what happens. You guys can see the array, right? So that's the on and then off. So once again, it will record the off. And it may be like I said, every 20 minutes interval for a duration of three hours. Ideal temperature is 26. And then here you can see once I submit it, user config stored successfully. I'm not sure what's happening here. But nevertheless, this is the idea of this little device that I need. So let me go through a little bit more on the hardware. So once again, everything is on iPad and schematic is there. So if you look at the subsystems, the way I did it, let's look at a power management system first. So we have the way I did it is now this guy, I can also put it with a battery pack here. So I can make it such that this has two connectors here. And the PCB can come in here. And you see, I can turn it on. And whatever I programmed inside will be there. But at the same time, so this is the USB. And at the same time, it can also use the battery connector. I use the P channel MOSFET to turn it off, which power source it's using. Of course, it has a low drop out LDO regulator, which will put it down to 2.8 volts. That's what the microcontroller can take in. So this is the microcontroller. Lots of stuff there. But I guess if I go through the subsystems, you guys will understand better. So here's the IR receiver here that I talked about. This is the black color one. And that's how the IR codes were captured. This is the IR emitter. This is where the LED will kind of shoot it out to either the aircon, the Roomba or even Apple TV, any device that has IR. And finally, I put in temperature sensor. So based on that temperature, you can do certain actions. And finally, it has some status. So that is about the hardware. The main thing is, as you can see, it's really small. And this is like the first time I actually broke it out of the microcontroller board. It comes with a lot of things and just took the microcontroller chip here. So it's really tiny and handy. And of course, there's also a layout here. So in terms of the software, rather the firmware on board, I am using Arduino firmware. So there are two firmware libraries I want to point out. One is the IR2Lib2. And especially if you go here IRLib2, and then under examples, the one I used is raw receive and raw send because that's what I'm doing. I'm basically capturing any IR signal and sending any IR signal. And my favorite one, this is the WebUSB. That's how the exchange happens between the microcontroller and the browser. So this is what I'm using. Just to note about WebUSB, there are compatible hardware. So the one I'm using is Arduino Zero because the microcontroller must have the USB peripheral. So in terms of the microcontroller, I am using the Atmega SAMD21G. We always hear about the Atmega 3280, which is the Arduino Uno. This is slightly more powerful. There are three features different from Arduino Uno. Number one, it has more flash storage. And I needed that because I needed to store the IR code, which Atmega 3280 could not do. And number two, it had a periodic wake up and sleep, which Atmega 3280 did not have because it does not have a real-time counter on board, but this guy has. And number three, WebUSB. So this is one I'm using. And of course, in terms of the firmware, I am using the Arduino Zero firmware. So once again, you can go to hudskip.com slash pine. Let me talk about the bill of materials. I felt this project is fairly cheap because there was no wireless. I mean, the only wireless is infrared. And infrared is a very old technology. So if you're using IR, there is only the LED receiver and emitter. And almost every remote control has it. And I think remote control is like a 30, 40 years old in mass production. And the most expensive thing is basically the microcontroller and the battery connector. I believe the temperature sensor as well. So it was about US $10. And in Singapore dollars, it's about $13. But I think I had some parts that I could use on my own. But really, within $20, you can easily do this project. Please go ahead. You can also download the bill of materials here. I bought it from LCSE and RS components. And I manufactured the PCB from JLCPCB. And my husband helped me solder because I was pregnant. All right. So in terms of design, this is the subsystem level. I think I spoke about it. The microcontroller, the battery and the micro is we can power the entire project. It goes through an LDO and then the microcontroller. And then in terms of the subsystem, there are four of them. So I finally want to talk about the programming connector. So this microcontroller, when it first comes, you need to upload the bootloader, the Arduino bootloader on it so that we can write the Arduino code. And in order to do that, like I showed in the hardware, so if I go to the hardware in schematic, there was a section on the SWD programming. And that's why I had put in the six pins here. And the way we finally did it was to use these Pogo pins and press it against these six holes and then program it using this J-Link. I had to go through a lot of, because this is the first time, I think this was the most difficult part for me. Actually, this is still, I borrowed it from one of the Hackware users. I think I even posted on Hackware, hey guys, you know, I need this J-Link. And somebody helped and posted, do you remember the guy's name? He actually gave this to me and I still haven't yet given it back. So that's how I uploaded the Arduino bootloader, which I think I should also show on real standard 21G bootloader. So basically it is this one, it's also another GitHub repository so this is the repository that has the bootloader and if you go under the bootloader, basically all the SAMD ones, of course the one I chose is zero. So you have to compile the bootloader and you have to upload it. Of course, when you buy Arduino zero, it comes with it, but when you're making your own PCB, it does not see you have to upload the bootloader. So that was a very challenging part for me. So that's in terms of the design, the bootloader. Let me talk about the lessons learned as the final thing. So I would love to know from any one of you who have made IR-based projects, I would love to use SMD components next time. I don't even know whether I should because I would love to get it all assembled in a pick-and-place machine, totally automated and I think through all components you have to manually do it. I would love to look for SMD components for the IR receiver and which you can see it's kind of sticking out. I also would love to use a 19 JTAC and SWD connector. Like I said, I have to use a Pogo pin and kind of like press it on, but instead of that I will use the 10 pin standard connector that comes for SWD programming. So yeah, that's about it. The rest of them are kind of general lessons that I took from other projects. Oh yeah, about the reverse polarity circuit. So I used basically a simple for the reverse, let me show you the reverse polarity. So in order to protect the PCB, I use a diode basically, a shocky diode, but I think a better way to do it will be to use a P-channel MOSFET. So under lesson learned in my next version, I think I'm going to use a P-channel MOSFET for reverse polarity circuit protection. And yeah, what else? I think, yeah, that's about it. Did I take a lot of less time? But yeah, you can go and visit this project and all the references and whatever I did is all here. I don't know how much time I took. Okay, thank you, Saiyani. Anyone has any questions for her? Two questions. One, did I see correctly that your reverse polarity protection was a diode? Roland, you're a bit soft. Right, how's that? Yeah, that's great. Did I see correctly that your reverse polarity protection using a diode was done by having the diode connected backwards across the battery? Did you toss that out? No, I did not. I did not. I did not test it. No, I did not. That's why, yes, I know. Yes, I know. This is it. Have you seen Roland? Yeah, yeah, yeah. So, all I was going to guess. This is it. Yes, I know. I know. That's why in the lessons learned, in the lessons learned. Put the diode in series in the right direction, not in, wow. That's, I mean, impressive. But the question I wanted to ask really was about the motivation for turning the air conditioning on and off in the first place. Yes. Speaking of someone who first had to live with air conditioning all the time when I moved to Singapore a bit over a decade ago, I have a whole set of frustrations and concerns. But I was wondering, is your concern principally comfort or cost or some combination of these? It is mostly comfort. To be honest, for my second version, I would probably want to have it Wi-Fi enabled as well so that I can actually control it. Right now, if you notice, I cannot control it. I can only program to do certain things by itself. So, it's mostly definitely comfort because I need to turn it on. Like, for example, to be honest, I found new users to control it after having a kid. Like, she's sleeping inside and sometimes I forget to turn on or turn off the air con for her comfort. And I cannot go in because it's dark and I do not want to disturb us, but I can just turn it off from outside. So, things like that. Or even in the middle of the night, when I wake up, sometimes I do not want to stay awake just to turn it off after a while. So, I just want to turn it off after a while. Just a sort of background question. I've noticed that the thermostats for air conditioners, perhaps it's true over in the world, of course, it had to deal with a person directly only in Singapore, never seemed to want to turn the compressor off. Even if the room temperature is several degrees below the target temperature, the compressor stays on, and it just keeps pumping cold air into the room. This is in office systems and home systems. It seems a universal thing that says the thermostat only ever changes how hard the compressor works, but it's never an option to turn the compressor off. I suspect there's a power cost with starting the compressor, but it's a treat to know whether you're, because my backup question is how do you study the power use? But that's a separate question. How are you sort of this guy? No, the air conditioning unit. No, I did not. I did not. When you turn it on and off versus leave it running on its own thermostat. Okay. It's a question I have. I want to do myself at some point just to Interesting. Yeah, that's an interesting thing. Yeah. But actually measure the power use, because my guess is that the turning the compressor on and off is probably consuming a great deal of power. Okay. Because the inverters that are now in use are extremely efficient. They write down the coasting level, but not actually off. Anyone has any other questions? If not, I think we can move on.