 my name is Ben. So recently I got into urban farming and I'm interested in things to do with growing plants. And also part of that is composting because the food waste can be turned into compost which is like natural fertilizer which you can use to create your own soil for growing your own food. So it's like a circular loop, like closing the waste loop. Okay, so for those of you who are not familiar with what composting is, I have on my screen a picture. Can y'all see my screen? Okay, good. So this is what I call traditional composting. So traditional composting is very simple. You're just alternate green layers and brown layers. So what are green and brown layers? So green layers are your food waste because it's normally green in colour, you know, like vegetables or food pills, you know, they're very colourful and they are usually green, like green glass glass kippings. And then browns and they're actually wet. Okay, browns are things that are actually brown in colour and dry. So they're things like newspaper, cardboard. It can be dried leaves, brown colour dried leaves. It can be cocoa peed. Cocoa peed is what we use for our machine. Cocoa peed is very good because it's made from coconut husk. It's basically like the leftover shavings from coconut husk. And it's very good for putting in the compost bin because of the properties, very fluffy. It absorbs a lot of moisture and it's very good for like encouraging microbes. So traditional composting relies on microbes to break down the food waste. It takes, depending on how you do it, it can take anywhere from like two to three weeks to like maybe two to three months, depending on how you do it. So the way we are doing it for our machine, because it's not like a big machine, it's quite small, you know, like a bending machine size. So we decided to use a normal trash bin, like a rubbish bin. So it's not very big. So we've now reached the high temperatures that we want for very fast composting. So we are normally, we're doing it for like over two or three months. So the idea is that once the bin fills up the gardener or the maintainer of the machine needs to take out the bin and then empty up the contents or replace with the empty bin. Okay, so we are using the traditional bin composting method. So imagine this is a compost bin. Okay, so next I'm going to show you, like before the project started, we had like ideas of what how it's going to look like and how it's going to work. So we asked like, this is a volunteer project. So I'm also like a volunteer. So we asked somebody like a student to create a short video of what the bending machine would look like or great. Okay, so this is at Amokio community garden, that's community garden. Okay, so the compost bin is over here somewhere here. So there's a keypad over here for the user to unlock this door. There's a door over here, access door. So there's also a RFID card reader or keypad. So you can enter a very short password to unlock this door. Okay, so when you unlock this door, inside, this is the top view from looking out from the top view, the brown containers, it's the one that contains the coco peat, the coco peat, right? And then there's a grinder, this is the top view again. Okay, then there's a weighing scale over here. Yeah, and then there's a screen, they continue the video. So you need to put your food waste into the grinder, there's a funnel for you to put the food waste into the funnel and then there's a grinder. So you turn on the grinder by pressing the start button. And then after you're done finishing, you have to press the stop button to stop the grinder. And then you have to turn this knob on the brown container to add a layer of brown onto the compost bin. So composting, we try to avoid meat waste, dairy products, grease and oil because these will attract pests like rats and cockroaches and all that and we don't want that. And it will start, you'll sync up the bin as well. So we can only collect certain types, the best would be vegetables and fruit, basically non-processed food, non-processed food, natural food. Then one of the outputs that we need to weigh to find out how much food waste is collected. This is the funnel for putting the food scraps. Yep, so that's the video. And then we came up with a block diagram or, no, okay, first of all, it's a flow chart. So based on our discussions, we came up with a flow chart. This might not be a very proper one, but it's a very quick one. Okay, so the video loops in the idle mode and then you can open the door either by using RFID or a code on the keypad. Okay, then once it verifies that the person has entered the right password or the RFID card, then you unlock the door with a message, welcome message, and then you'll ask the person to start adding the food scraps into the grinder. So you press the green button to start grinder, then you add your food scraps into the funnel, maybe grounded, you'll be grinded, and then you will be deposited in the compost bin below. And then after it's stopped, then you, because the grinder is not attached to the microcontroller, we need to actually tell the user to tell the microcontroller that it's done by pressing the keypad. So I ask the user to press the x-rings button, or, no, sorry, the hash, hash, hash tag button, hash button, yeah, to tell the program that they have finished the grinding. Then after that program will tell the user how much food waste was contributed, and then you'll ask the user to turn the knob to add the layer of grounds. And then again, because the knob is not automated, it's not connected to microcontroller, so you need to tell the microcontroller that you're done. So you press the keypad to tell the program that you're done, adding the grounds, and then the program will tell the user. Okay, then we came up with the block diagram. So this is the components that we use. There's a keypad here, the RFID reader, the 50kg load cell, which is this HX711 is an amplifier that will amplify the signal so that the Arduino is able to pick up the signal from the load cell. Okay, then we are using two ultrasonic sensors to, one is for the ground to find out how full the ground is to track whether it needs to be topped up. If it's empty, then we need to tell the maintainer of the machine to top up the ground. And this one's for the compost bin. So once the compost bin is full, we need to tell the governor to replace the compost bin. Then there's the solenoid block for the door. Then we need ventilation for the electronics, and also the compost bin because compost needs oxygen for this aerobic process, which needs oxygen. So it's good to have ventilation in the machine so that you have the compost as well to break down. Okay, so this is a demo or okay, so I'll show you a demo actually right there. Okay, so this was like, before we installed it on the machine, this was like the breadboard stage. So I use the Raspberry Pi for the, I use Python on the Raspberry Pi to create a very simple program. So, so do we know talking to the Raspberry Pi? The Raspberry Pi runs a Python program with the simple user interface. So, so, oh, sorry, I think I ran a bit too fast. Let me start with it. Okay, so it starts on the idle mode, which is the video loops on the idle mode. And then I use the RFID tag to unlock the door. And then the program hotel will welcome the resident and then tell the resident to start processing the food waste. And then, oh, okay, so I put the RFID tag there to stimulate the food waste. So pretend that it became heavier, it became heavier with that tag. And the tag weighs four grams. All right, so the load cell is able to detect a resolution of four grams. Then I'll tell the user to turn the knob and then press the hex button when they're done. So press the hex button. So the user has finished. So tell the user to close the door and go by. Okay, so, oh, one interesting thing is that we had to last minute, we found that the ultrasonic sensors didn't work because the cocopeat is very soft and fluffy. It actually absorbs sound. So we found that it couldn't detect the cocopeat, like you can read it like minus one. So we had to change to an infrared sensor at the last minute. Okay, so yeah, we are using infrared, infrared works with soft fluffy materials. Next thing I'll show you is, okay, yeah, this is what the machine looks like. Okay, so like this is the grounds container, this is the screen, this is the door and this is the panel and the grinder. So we use a liner. This is an ammo cube near the community garden. This is what you call, it's not a final product, this is what you call the MVP, the minimum viable product, still not working very well. Oh yeah, this is the infrared sensor which we put, see like this points downwards towards compost bin. So this will detect how full the compost bin is. This is for the grounds container, the IR sensor for the grounds container. Okay, so like this is the, this white box is the Arduino Mega, we use Arduino Mega and this is the Raspberry Pi 4 in the black box and we use a Wi-Fi dongle video. The ventilation fan is behind. This is the at the back of the RFID card reader. The RFID card reader somewhere in here, the lock is here. This is the back. This is the testing with the Pocopy and the IR infrared sensor. Okay, I think the rest are not very interesting. Yeah, okay, then the next thing I'll show you is things speak. So I'm using the free version of things speak which allows you for up to four channels. So I maxed out the four channels and actually today was like the first day that we started collecting data. So the first data that we need to track is the RFID tags we, we've given out like, we've just prepared like maybe about 20 tags and we named them from one to 20. So this RFID tag nine, eight and one and so on. You see it's still not working very well. Like I think it's, my program is still a little bit buggy. Like sometimes, okay, like this is food waste contributed. Okay, this, this sounds legit, like 178 grams legit. 421 grams is legit, but occasionally you get like a negative like 400. I'm not sure why. I think my program is still a little bit buggy. And then this IRR sensor, the bin is for the compost bin. So over time this will fill up. So the bin fullness will go out slowly, right? This should slowly go up, but the IRR sensor is not working very well. So it's like 50% most of the time, but sometimes you get like a 40, yeah, 1%, yeah, that's not working very reliably. And this is the browns container. So the brown should go down over time as you use up. So this should start from like a high number and it goes to zero slowly, but it's not working very well. I need to debug it. Yeah, so it perverse around 60%. Yeah, okay, that's it. So I'm actually was wondering if like anyone would be interested to help out with this project. We're trying to get some funding for the next situation, but this is a non commercial project, it's a community project. So if you want to learn to find out like I also want to learn. So I'm not a professional engineer. So I would need like, I'll probably be asking people that know more things than me about how to like mess, mess, produce this, like lower the cost and then how do you go to mass production? Like, like maybe we start in by the third of all iteration, you want to increase the number of machines and I don't know a few hundred. I don't know. Like, so like some ideas I have now, of course, we need to come up with some sort of PCB for the circuit. Then you can mess, the software is not issued, right? Software is quite easily scalable. The hardware will be issued like a frame and all that, but I'm not taking care of that. So that one, I'll leave it to the experts, other people, other people do it. But the software we might want to use, like, like some sort of cloud service for collecting data for many machines at the same time, instead of using a free version of things, for example. And of course, the user base has been improved. Like now it's just bare minimal. So we get designers to come in to make a very nice user interface. And also, of course, the sensors need to be working reliably. So there's still a lot of room for improvement. So if anyone is interested in this project, do let me know. And then I can add you into the kit up page. And then I can also invite you to come and get me that once in a while to think about the next situation, how to improve on it. So do let me know if you're interested in this project. This is a non-commercial project. So I think there's no issues about, I don't know, like proprietary stuff or stuff like that. Okay, I think I'm pretty much done with my presentation. So good for questions. Yep. Thank you, Ben. Yeah, anybody has questions for Ben on this project? Oh, wait, I just want to share something with you. So I found out there's this thing called VNC Connect, which is really cool. So what this thing is actually like, VNC Connect is like a software that allows you to look into your remote device. So I name it Raspberry Pi. I mean, it's a demo, I'm at home now. So I'm actually able to log in, like to see what's on the screen on my Raspberry Pi in real time. And then I can even like, I can even like, control the Raspberry Pi from here. Like you type it or use the mouse or you type commands into, you're using it, like you're actually physically there. So I think this is really cool. Like, okay, so now the video is playing, I don't know. This is what's happening on the machine now. So you can actually like toggle. Yeah, you can actually exit and then you can go to the desktop and all that. Yeah, I'm using a Mac now. So I don't know how to quit this on my Windows. I can just quit this, but I have to figure out how to quit this on my Mac. I'm using a Mac now. So yeah, but you get the idea. You can control it like you're physically there. So it's really cool. Yeah, okay, that's all. Yes. I have a question, Ben. So I'm just curious, you know, what's the use case for, you know, because I think you have in place, you know, some kind of authentication. Is that right? Yeah, what is the purpose of that? We don't want people to like, because we want to train people, we want only like the residents of that block or people who know what the machine is about. We want to restrict the number of people to use it for now. The idea is that it's for the community garden. So actually, we are only targeting like the local residents in that area. We don't expect people to travel like from somewhere else to just use the machine. So it's like a thing a bit like a vending machine for those one or two blocks of the most two or three blocks on that that surrounding the community garden. So we want to restrict the number of users. Then we want to train like just a quick like to train the users and how to use the machine, what composting is about. Yeah, so yeah. It's more like, you know, you authenticate that the person has been trained and you know, experienced user and local user. And as a resident also, so we know like this tech number, like which unit number is allocated to a tech number. We know who has contributed. We want to keep track of like who like which unit. So let's say we have like 100 techs and then like there are 100 units in the HDB block. So we know like which unit has like contributed how much food waste. Yeah. Okay. Yeah. Anybody else has any questions? You know, if not, nobody. I have a question. Yes. Who is this? John. Yeah. Okay. Can you hear me? Yeah. So while composting, right, do you have to deal with methane gas or anything like that? Okay, no. So if you do it correctly, right? If you do it correctly, that means you are able to let it breathe. So we put, we actually drill holes in the compost bin so that the air can flow through. So it's an aerobic process. So if you do it correctly, like there's, it's not supposed to have any kind of funny smell. If you do, there's a funny smell. That means it's what you call an aerobic and there's a lack of oxygen and you'll have this like ammonia smell and all that. So that's, that you're not doing correctly. So the correct way is to actually alternate layers with greens and browns. Yeah. So if we do correctly, there shouldn't be any kind of weird smell coming out. In fact, it should smell nice. Yeah. So if there's an off chance, right, of methane gas or any combustible gas producing no, no, no, no, no, no, no, no, no, no, no, no, no, no, no, no. It's not fantastic. That's no way they think gases produced. All right. Okay. Yeah. Yeah. It's just, just covered the outside. It's like the microorganisms, they need oxygen and then they, they respire, they give up on the outside. Yeah. It's a fan to circulate the air. Right. Not familiar with composting. So I thought that I'll produce here. Yeah, bad odors will happen if you put in things like milk, dairy products or oily food or cooked food or processed food with a lot of chemicals, then the microbes are not able to break it down because it's chemical, you know, it's not like food for them. Whereas if you put like cardboard, newspaper, eggshell, coffee, coffee grounds, tea leaves or vegetable and fruit waste, these are things that in nature the microbes are able to break down. So they'll be very happy. That's why we do trade with people. That's why we want to restrict people who use the machine because if they start adding tiny things in there, they'll cause problems. Okay, yeah. Thank you. Yeah. All right. All right. Thank you very much, Ben, for sharing. Yeah, I think Ben, will you still be around? I think you'll be around after the meetup, you know, to answer any, to hang out and then you answer any questions you may have. Yes, and I think for information, there's a lot of local community groups in Singapore that does composting. You can Google search Project Black Gold as another composting project.