Project Development

1. Our Team Chemical Device

Cooking a soft-boiled egg is a delicate process. A little too long and it becomes overcooked. A little too short and it’s raw.

In order to get the PERFECT soft-boiled egg, the perfect timing and cooling will be needed.

We came up with an idea to automate the cooking process to cook the perfect soft-boiled egg every time.

This can be done by draining the hot water from the egg after it is cooked after a specific time. 

The temperature sensor will first detect a change in temperature which sends a signal to the Arduino board to start the delay for 7mins. After 7 mins, the Arduino will open the valve for 1 min to drain all the hot water. In our final design, we did not use a temperature sensor, instead, we used the button on the Arduino Uno Board to start the delay of 7 minutes. This was to reduce the complexity of our chemical device.

Drawing of Chemical Device

2. Team Planning, allocation, and execution

Our team consist of me as the Chief Executive Officer, Vernon as the Chief Strategy Officer, Nigel as the Chief Operating Officer and Roy as the Chief Financial Officer.

This is our finalized Bill of Materials (BOM) table:

Planned Gantt Chart:

Due to some problems arising during the project development stage, our actual timeline was different from what we planned in our Grantt Chart Here is our finalized Grantt Chart:

Link to planned and finalized Grantt Chart: https://drive.google.com/drive/folders/1Gux7qvP9RXdP055vj5zmysM5eZiOxtmn?usp=sharing

In order to complete our project on time and efficiently, we distributed the workload equally among our group members. Arduino Programming: Done by Nigel Designing CAD for 3D Printing: Done by Bjorn 3D Printing of Parts: Done by Roy and Vernon Assembly of Prototype: Done by Whole Group Gathering of Materials: Done by Whole Group

3. Design and Build Process

In this section, provide documentation of the design and build process.

Part 1. Design of CAD and Valve Mechanism Schematic done by me.

Design of CAD for 3D printed parts:

CAD of Valve Disk

CAD of Valve Connection

For the designing and printing of parts, we had to design and print 2 parts for our prototype, valve connection, and disk, 2 of each.

For the valve disk, I created a circle of diameter 50mm, drew 2 smaller circles of diameter 7.6mm and a small rectangle in the middle of dimensions 3.6mm x 5.2mm. Lastly, I extruded the sketch by 5mm.

For the valve connects I drew a larger circle with a diameter of 25.4mm, a middle circle of 12.7mm, and a small circle of 7.6mm. I extruded the outer circle by 5mm, the middle circle by 21.55mm, and left the small circle not extruded.

I designed the middle hole of the valve disk to be the same as the stem of the stepper motor so it fits snugly onto the stepper motor. Since the tube we purchased had an internal diameter of 12.7mm we also designed the outer diameter of the valve connections to be 12.7mm to fit the tube. The holes of the disk were designed to have a sufficient flow rate when water is being drained. The thickness and height of the disk and valve connection were chosen to have a smaller form factor for our valve mechanism.

Hero Shot of CAD

Valve Mechanism Schemetic

Since we will need to drain water out from the container, we need to design a mechanism to act as a valve. Thus I created a schematic so we can base our valve mechanism design out of it.  We used the parts we created and purchased to make this valve mechanism. When the holes are aligned, water is able to flow through. When the disk rotates by 90 degrees the straw will get pinched thus stopping the flow of water.

Part 2. Arduino Programming (done by Nigel)

link to Blog: https://cp5070-2021-2b02-group3-nigel.blogspot.com/2022/02/project-development.html

We wanted the stepper motor to be able to have a 7 mins delay before turning 90 degrees for 1 min and then turning back to a close position. This will be run when the button on the board is pressed. In order to start, I had to copy and paste the code from the seller's website as it contains the code which allows the motor to move. Then in the void loop, I start off with the Toggle Button code in my Arduino Practical blog (DC Motor part) since I will be using it to run the code. Then I added a delay for 7mins (420000ms). The stepper motor has 2048 steps per revolution so, in order for it to turn around 90 degrees, I added them for a loop. Initial a (number of steps) = 0, a will keep on adding until it reaches 500 steps (90 degrees). Now I have to add the delay for every step and the direction. The minimum delay I found on the website is 2ms per step so I add a delay of 2ms in the for a loop. OneStep(false) is the direction of the step which is defined by the initial code. Currently, it is turning in a clockwise direction. For that, we wanted it to stay at this position for 1 min in order for all the hot water to drain out, and hence we added another delay for 1 min (60000ms). Lastly, we wanted the motor to turn back to its original position, so I copy the first for loop and paste it at the bottom, and changed the direction to anti-clockwise, OneStep(true) to OneStep(false). 

Here is what the code looks like:

File for the code: https://drive.google.com/file/d/15UW6aG8j52MsCDbGREOLuV5RaiDPSKtf/view?usp=sharing

Part 3. Brainstorming for the prototype (done by Roy).

Link it to Roy’s blog: https://cp5070-2021-2b02-group3-roy.blogspot.com/2022/02/project-development-entry.html

For the assembly process, from what Bjorn designed and Nigel coded, my main task that I spent the most time on was to get the prototype working as well as come out with new ideas when the old failed. 

Initially, we were following a different design:

However, due to issues we faced, we had to drop this idea completely. So the team and I started brainstorming. I came out with the idea to try to implement a vacuum and to perhaps use a tap as a start-stop valve.

But the final idea that we implemented was thought of by Vernon. I did a sketch after the idea has been selected and tried to visualize the design:

We spent the next day in school to try to implement the design, such as fabricating the initial tube, mounting of motor, and testing the mechanism:         

Part 4. 3D Printing of  Parts (done by Vernon).

Link it to Vernon’s blog: https://cp5070-2021-2b02-group3-vernon.blogspot.com/search/label/8.%20Project%20Development

To use the 3D printer in the workshop we had to book the printer we were going to use. Before going to workshop to use the printer, Bjorn had sent me the file of the CAD parts he designed. My job was to goto W3 to print and troubleshoot if problems were to arise.

Here is the Cura setting I used for the printer which was the Creality ender-3. I used the same settings for both parts we printed.

A small issue that arose was the sizing of the square was a little too small which we found out after the first print. It was a easy fix as we just need to adjust the length and width of the square.

Here is the photo of the parts printed.

In total i printed 5 parts. It took slightly more than 4hours to print all 5 parts. The first part was defective as it was the wrong size.

Here is a short timelapse for the Disk.

 

Part 5. Integration of all parts and electronics (done by the whole group)

Firstly, we connected the valve connection to the container using some silicone sealant.

Next, we connected the tube to the valve connection and container using some silicone sealant.

Next, to create the valve mechanism. We then used duct tape to secure the valve disk and motor onto the bottom of the container.

We then started on the wiring of the motor to the Arduino board. The 5V pin of the Arduino board was connected to the '+' pin on the driver board. the ground pin on the Arduino Board was connected to the '-' pin on the driver board. Pins 9, 10, 11, 12 were connected to the driver board as stated in the Arduino code.

Lastly, we added the waste container on the bottle and the electronic housing.

Hero shot of the prototype:

Video of valve mechanism in action:

Product Demonstration Video:

Finalized fusion 360 design files:

Valve Connection:

Valve Disk:

4. Problems and solutions

In this section describe the problems encountered in the design and build process and how the team solved them.

Problem 1: Parts Breaking

We had quite severe issues after we first constructed the prototype. 

After assembling it in school, we ensured that it was in good working condition. 

We proceeded to leave it overnight. But when we opened up the prototype the next day, the stepper motor corroded badly due to water leakage, and our tube broke. We had another stepper motor that we had to switch to in fear of safety. Thus we needed to recreate our prototype. 

Our final prototype failed due to the straw. As the straw was too rigid, after excessive use, it couldn't straighten back to allow for the water to pass through, which prevented the draining of the water.

Problem 2: Problems with our Initial Design

We had an initial idea where the disk is able to block the flow of water when the holes are not aligned and allow water to flow when the disk rotates 90 degrees and the holes are aligned. However there was a problem with our initial idea.

We tried to add sealant between gaps however, the friction between the sealant and the disk made it too difficult for the stepper motor to rotate. Our solution was to use the new design mentioned earlier.

Problem 3: Unable to use 12V Solenoid Valve

Initially, we wanted to use a 12V solenoid valve. However, due to limitations and restrictions, we had to scrap this idea and design a valve mechanism ourselves.

5. Project Design Files as downloadable files

Link: https://drive.google.com/drive/folders/1cXuNUvqClMpqXbsQs_gDCVzex5HCwjKA?usp=sharing

Hypothesis Testing

 HYPOTHESIS TESTING TASK📝

For this assignment, We are tasked to use the DOE experimental data that your practical team has collected both for FULL Factorial and FRACTIONAL Factorial.

DOE PRACTICAL TEAM MEMBERS (fill this according to your DOE practical):

1. Bjorn Lim

2. Darren

3. Gwyn

4. Cui Han

5. Hai Jie

Data collected for FULL factorial design using CATAPULT A (fill this according to your DOE practical result)

Data collected for FRACTIONAL factorial design using CATAPULT B (fill this according to your DOE practical result): 

Bjorn will use Run #1 from FRACTIONAL factorial and Run#1 from FULL factorial.

Darren will use Run #7 from FRACTIONAL factorial and Run#7 from FULL factorial.

Gwyn will use Run #6 from FRACTIONAL factorial and Run#6 from FULL factorial.

Cui Han will use Run #4 from FRACTIONAL factorial and Run#4 from FULL factorial.

Hai Jie will use Run #4 from FRACTIONAL factorial and Run#4 from FULL factorial.

USE THIS TEMPLATE TABLE and fill all the blanks

The QUESTION	The catapult (the ones that were used in the DOE practical) manufacturer needs to determine the consistency of the products they have manufactured. Therefore they want to determine whether CATAPULT A produces the same flying distance of projectile as that of CATAPULT B.
Scope of the test	The human factor is assumed to be negligible. Therefore different user will not have any effect on the flying distance of projectile. Flying distance for catapult A and catapult B is collected using the factors below: Arm length =  24.5 cm Start angle = 5 degree Stop angle = 45 degree
Step 1: State the statistical Hypotheses:	State the null hypothesis (H0): Catapult A and B produce the same flying distance of the projectile. 𝜇A = 𝜇B Assuming µ is the flying distance of the projectile. State the alternative hypothesis (H1): Catapult A and B do not produce the same flying distance of the projectile. 𝜇A ≠ 𝜇B Assuming µ is the flying distance of the projectile.
Step 2: Formulate an analysis plan.	Sample size is 8 runs. Since 8 runs is a small sample size, Therefore t-test will be used. Since the sign of H1 is ‘≠’, a two tailed test is used. Significance level (α) used in this test is 0.05
Step 3: Calculate the test statistic	State the mean and standard deviation of sample catapult A: Number of runs = 8 runs Mean = 229.2cm Standard Deviation = 5.78cm State the mean and standard deviation of sample catapult B: Number of runs = 8 runs Mean = 144.4cm Standard Deviation = 11.03cm Compute the value of the test statistic (t): At a significance level of 0.05, percentile is the 97.5th
Step 4: Make a decision based on result	Type of test (check one only) Left-tailed test: [ __ ]  Critical value tα = - ______ Right-tailed test: [ __ ]  Critical value tα =  ______ Two-tailed test: [ ✓ ]  Critical value tα/2 (t0.975) = ± 2.145 Use the t-distribution table to determine the critical value of tα or tα/2 Compare the values of test statistics, t, and critical value(s), tα or ± tα/2 Since the test statistic, t = 18.02 lies in the rejection region, the null hypothesis is rejected. At 0.05 level of significance, Catapult A and B do not produce the same flying distance of the projectile Therefore Ho is rejected.
Conclusion that answer the initial question	Since the null hypothesis is rejected, the alternative hypothesis is accepted. Catapult A and B do not produce the same flying distance of the projectile.
Compare your conclusion with the conclusion from the other team members. What inferences can you make from these comparisons?	My conclusion is the same as the conclusion from my other team members. However, my t calculated is much higher than the t calculated by my other team members. This creates a larger margin in my t calculated and the t0.975 value. This shows that Run #1 from FRACTIONAL factorial and Run#1 from FULL factorial has a much more significant difference in the flying distance produced by catapult A and B. Since our conclusion is consistent for all the runs, the comparison shows that catapult A and B do not produce the same flying distance even when the settings (arm length, start angle, stop angle) are changed.

Conclusion:

For this task, we were able to use the data we collected in our previous DOE practical to perform hypothesis testing. We were already able to practice hypothesis testing during our tutorial lesson however, I was not able to grasp the reason for using this tool. This exercise really helped me to understand how and when to utilize this tool as we were able to perform the calculations using real data we collected. During the DOE practical, I already hypothesize that the 2 catapults produce very different launch distances however by looking just at the pure data, it is not easy to prove the significance of my hypothesis. By using the hypothesis testing tool and calculating the values, I am able to prove my hypothesis. As a person interested in math and numbers, I really found this task interesting.  I will try to use this tool in the final project if CCPD if we were needed to perform any experiment for data collection and we need to prove our hypothesis. 

I used to think that we were able to prove our hypothesis just by looking at the raw data of an experiment. However, how after learning how to use the hypothesis testing tool, I believe that this tool is a definite way to prove our hypothesis using numbers and calculations. I believe this tool will be a life-saver in the upcoming Capstone project in year 3 as experiments will be inevitable and we will need to prove our hypothesis as part of our assessment,