Project Development
Project Development
For this blog, I will be documenting the design journey for my groups chemical device which is a CO Detector and ventilation system. Since this is the "End Game" of this module and is what all the previous blogs and lessons have been building up to, this shall be the last blog that I will be documenting for this module. For our CO ventilation system, we had to use knowledge and skills that we had learned from this module as well as previous modules such as laser cutting, Arduino programming, 3D printing etc. After some discussion and planning, we had decided to use Arduino programming to make the gas detector and fan work and 3D printing to make a housing for all the components.
My group consists of myself, Wayne and Yiren and we will each be talking about our product as a whole as well as splitting up the blog entries into 3 separate parts so as to save time. Apart from the general information that all of us will be documenting in our respective blogs, each of us will be diving deeper into a specific part of the CO system design and implementation process. I will be documenting the 3D printing portion, Yiren will be documenting the Arduino Programming portion and Wayne will be documenting the CAD portion.
Description of Chemical Device
The use of a CO Detection and Ventilation System is an important device which can potentially save one’s life.
CO will bind to haemoglobin that's found in the red blood cells inside your body. This will decrease the amount of oxygen that haemoglobin can bind to and hence carry, thus humans will face difficulty breathing when too much CO is inhaled. When CO binds with haemoglobin, this reaction is irreversible. Therefore, when too much CO is inhaled, one may lose consciousness and die due to lack of oxygen.
CO can be produced easily, even in homes. Some common sources which produce CO are clothes dryer, water heaters, boilers, fireplace, gas stoves, ovens, motor vehicles and tobacco smoke. Furthermore, since CO has no odour, colour or taste it cannot be detected by our naked eye or by our senses. This means that dangerous concentrations of the gas can build up indoors and humans have no way to detect the problem until they become ill. When people become sick, the symptoms are similar to flu, which can cause victims to ignore the early signs of CO poisoning. Without proper detection and ventilation, humans can easily die to CO poisoning. Thus, the CO system device is an essential and important device which can help save human life.
The CO device can detect carbon monoxide in the atmosphere which is dangerous when inhaled. The CO Detector and Ventilation System is controlled by an Arduino, and will be able to able to detect Carbon Monoxide (CO) in the atmosphere. If CO is present, and is above the set threshold value of 175PPM, the ventilation system, which consists of the motor controller and the motor with a 4 bladed fan, will start spinning to help remove CO in the enclosed area to an outdoor area.
When CO concentration in the atmosphere is below threshold value, a green LED will be lit up and serve as a visual representation for the people in the room so that they know the area is safe for them to be in.
However, when CO concentration in the atmosphere is above threshold value, a red LED will be lit up and serve as a visual representation for the people in the room so that they know the area is unsafe for them. There will also be a buzzer (audio alarm) sounding to alert everyone in the room in case the red LED cannot be seen due to external conditions such as harsh sunlight. People in the room will also be able to do the necessary actions such as opening the window to further decrease CO concentration and can also leave the room while the ventilation system is on, and helping to ventilate CO out of the room.
The CO Detector will be housed in a small sliding lid box, while the Ventilation System is found outside of the box. The entire system can be attached onto the wall using a strong tape near a window so that effective ventilation can take place.
Team Plan & Formation
Members | Allocated Roles |
Lau Jun Foong Wayne | CEO, in charge for the Design and CAD of the Chemical Device. |
Rong Yiren | COO, in charge of Arduino UNO and Coding of the Chemical Device. |
Wong Kea Tzer | CFO, in charge for 3D Printing and the Construction of the Chemical Device. |
Bill of Materials
Allocation of Documentation
Members | Allocated Roles |
Lau Jun Foong Wayne | Documentation of CAD |
Rong Yiren | Documentation of Arduino set-up and Arduino Programming |
Wong Kea Tzer | Documentation of 3D Printer Settings |
With the concept in mind, we now had to get into the details to make this CO Detector and Ventilation system come to fruition. The first thing that we had to do was make sure that the system worked as intended, which required us to programme and properly wire the Arduino and breadboard. Yiren, who was in charge of this portion, had modified sample code from the Arduino website so that he did not have to start from scratch. We then had to measure the dimensions of the completed Arduino set up so that we can create the housing for it in Fusion360. Wayne, was in charge of this portion. Once the 3D model with the correct dimensions was successfully created, the Fusion360 .stl file had to be imported into CURA for 3D printing and the final product had to be assembled. I was in charge of this portion. We used a Gnatt chart to help better manage our time and check that we are on track to completing the project. The link the the Gnatt chart can be found here.
CAD
The documentation of the CAD portion of this project can be found here in Wayne's blog
Arduino Programming
The documentation of the Arduino Programming portion of this project can be found here in Yiren's blog
3D Printing
Once the programming is done and the housing for the CO system can be accurately produced in Fusion360, it is time to export it for 3D printing. I will be walking you through our train of thought and the 3D printing process of our CO system housing.
I will be talking about the lid first as that was the easier print out of the 2 that had to be done. So for the lid, we left all print settings as the CURA default apart from the print speed. This was because we only had a total of 8 hours to finish printing everything and the lid by itself would have taken 3 and a half hours to finish printing if the default CURA settings was used. After consulting with the lecturers in charge, they recommended that we increase the print speed from 50mm/s to 150mm/s as that would cut the print time down to slightly under 2 hours. They also recommended that we use a raft for adhesion to make sure that the print comes out nicely. After all this was done, the total print time for the lid was 2 hours and 2 minutes and the settings used as well as some pictures of the process can be found below:
Now that the lid is done, its time to move on to the main piece, which is the box itself. Similar to the lid, the print would take too long using the default settings clocking in at 10 and a half hours to complete. Even after increasing the print speed to 150mm/s from 50mm/s, the time taken would still overshoot the 6 hours that was left for us to finish printing. We eventually decided to increase the layer height and initial layer height to 0.3mm from 0.2mm as that was the best option according to the lecturers. A raft was also required for the box to ensure that the print comes out as nice as possible as we didn't have time to print another one if this fails. With all these settings, the total time is well within our 6 hour limit, taking 5 hours and 21 minutes to complete. This 40 minute buffer turned out to be a life saver as we realised after about 30 minutes that something was wrong with our print. The base of the box was patchy and not flat, having bumps and crevasses everywhere. This happened because we had switched in the wrong filament that was not compatible with the settings used. The filament was switched as the previous filament reel was running out and we were unsure if it had enough left to complete our print. When this was realised, the lecturer in charge apologised as she had overlooked the type of filament when she recommended us to use this one. After this ordeal, we then switched to an appropriate PLA filament and proceeded with our print which would still finish within the 5 and a half hours that we had left thanks to that buffer. The settings used and some pictures of the process can be found below:
After both prints were completed, we had to remove their respective rafts which turned out to be harder than I thought. The raft for the lid came of cleanly and I managed to remove it with ease only using my hands. However, the same cannot be said about the raft for the box. It took me almost an hour to fully remove the raft by prying at it with a screwdriver. Although that was a painful experience that I would prefer to not experience ever again, the end result was worth it as the box turned out nicely and would work perfectly as the housing for our CO system. Below is a video demonstrating the box in action:
Problems & Solutions
Problem #1: Motor cannot be controlled
Solution: We consulted with Mr Mark who is very experienced with working with Arduino systems and he suggested that we use a motor controller as he had a spare one in the Makers Space. He was extremely helpful as he not only explained what was wrong, which was that the DC motor cannot be controlled using only the parts provided in the maker UNO kit as it would not allow for the DC motor to be turned off when the system is powered, but he also told us the necessary information on the new part that he gave to us which made implementing this new part into our system easier. With the help of this new part, the DC motor can now be controlled and turn on only when the CO level detected is above the set threshold and off otherwise.
Problem #2: 3D-Printing takes too long
Solution: With the default settings in place, the printing time for the whole box and the lid was estimated to be around 12 hours. To solve this problem, we had tuned the settings for the print speed. For an Ender Creality 3D printer machine, the default speed was 50mm/s. The max speed is 200mm/s. Thus, we had increased the printer speed to three times the default value, 150mm/s. This reduces the time needed to print the whole box and the lid to around 8 hours.
Problem #3: 3D printed Lid is unable to be slotted inside the hole of the 3D printed Box.
Solution: Using a file, the side of the lid and the clearance can be filed down to make the lid thinner and the gap larger. This was done until the lid could snuggly be slotted into the hole of the 3D printed box.
Hero Shots
Download the Files Used
In case you would like to try this project out yourself and recreate it, all the files used [Fusion360 files & Arduino Codes] in the project can be found here.
Reflection
In the beginning, we thought that this project would be very time consuming, and extremely tedious as it was our first time starting and doing on an actual project. The project given to us was to programme and develop a CO system which sounded very daunting initially. However, after weeks of tutorial lessons, we had gained more knowledge such as programming and 3D printing which gave us the skills and knowledge necessary to be competent for this project. Now, after successfully completing the project, we can say that it was not as difficult as we had initially thought. Instead, it has helped us to gain new skills, such as finding resources to help us with our project, and even problem-solving skills as unexpected problems may arise at different stages of the project.
Since we were assigned the project at the beginning of this module and every tutorial builds us up on the skills and concepts required to get us closer to completing the project. We tackled this project on a week-by-week basis where we would try and apply whatever we had learned from the tutorial that week into our project. This approach allowed us to keep everything on track and to not let the workload spiral out of control. Not only did this approach help us out with time management, but it also helped ensure that the work we produce is of the highest quality as we do it every week and are not rushing through it last minute.
We have learned a lot of things in this module and the biggest takeaway made from this journey is to always check that we have accounted for all the components in the design. With all this experience that we have gained, we now feel much more confident and competent going into our capstone project.
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