Project Development

 Template for Project Development Entry

Our team Chemical Device

So, our team came up with the idea to make an automatic tea maker that can make the perfect cup of tea. Our tea-maker will be able to adjust accordingly to the type of tea used to like Chinese tea, green tea, earl grey, etc. This is to ensure that the tea is made at its optimum temperature and steeping time.

Chemical device sketch:

  

Team Planning, allocation, and execution

Team members:

CEO - Miguel

COO - Jun Weng

CFO - Brayden

Planned Timeline:

Actual Timeline:

Task	Date (Time)
Brainstorming	1/1 - 4/2 (36 days)
Material Collection	18/1 - 4/2 (18 days)
Coding	20/1 - 13/2 (25 days)
Physical Creation & Integration	2/2 - 16/2 (14 days)

Task Allocation:

Task	Person In Charge
Brainstorming	ALL
Material Collection	Jun Weng & Brayden
Design & Laser-Cutting of Housing	Jun Weng
Coding of Components	Miguel
Design & 3D Printing of small parts	Brayden
Assembly & Integration	ALL

Design and Build Process

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

Part 1. Design and Build of Housing (done by Jun Weng).

https://cp5070-2021-2b02-group2-junweng.blogspot.com/

Part 2. Design and Build of gear & rack (done by Brayden).

https://cp5070-2021-2b02-group2-brayden.blogspot.com/ 

The video below shows how the Prototype of a smaller gear and rack came about. To test out whether the dimensions for the final gear and rack are usable, I decided to make a miniature version of the final gear and rack to test it. After knowing that it works, I left the 3D printer to make the hour-long final print.

The photo below shows the miniature gear & linear rack

The video below shows the first gear and rack design for the final design. I left this video in as I wanted to explain how the gear came about and how in the future, other people can find out how to easily make a similar gear to shape it to however they want. There is a script in Fusion360 that allows one to be able to make gear and this is something that I highly recommend as it not only cut down time but allows users for easy editing of new gear.

The photo below is the printed gear

For the video below, this is how I made the linear rack for the gear. So first of all, I made one of the teeth for the rack. I tried to imitate the teeth from the gear so after getting a generic shape where I felt happy about it. I duplicate the teeth along with the rectangle with the parameters I choose. After communicating with my group members, I found out that I need to make 2 protruding tabs with holes in them so they can each hold the temperature sensor and strainer. There is a picture that shows 2 racks and the top rack was rejected as there was a defect hence there is a reprint that is shown at the bottom.

The photo below is the rack in the process of being printed

The photo below is the failed rack and final rack

This is the rack that was designed and printed. After the print, I realised that I did not increase the BackThickness from 5mm to 30mm. This has caused the overall structure to not be as long as expected and it caused some problems where the strainer did not have sufficient space to be used. I have only realised this issue after assembling the final product and we did not have sufficient time to do another print hence we just went with this rack.

Part 3. Design and Build of supports (done by Jun Weng).

https://cp5070-2021-2b02-group2-junweng.blogspot.com/

Part 4. Programming of Motor, LCD & Temperature Sensor (done by Miguel). 

https://cp5070-2021-2b02-group2-miguel.blogspot.com/ 

Part 5. Integration of all parts and electronics (done by all members)

Embed the finalized fusion 360 design files.

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Documentation for integration.

Once all materials were ready, we put the housing together first. With the slots, it was easy to secure. We then added the cubes onto the corners, and then finally secured the slots with hot glue. The hinge for the door was put together with adhesive tape.

Next, we put the components inside. We set up the breadboard externally first, with connections to the components done later. We put the breadboard in the center of the base, and components at their respective holes laser cut previously.

The Arduino board was then placed on the side so that there is less tension between the wiring of the components and the breadboard. The Arduino board would be powered by a power bank.

Once the wiring was complete, we put the support onto the rack and attach the rack’s teeth to the gear’s teeth. After testing there was too much force on the rack that it cannot move. Hence solid scraps had to be used to keep their shape and allow for movement.

Finally, as the rack could not fit the weight of the sensor, we placed it on the side of the housing. Here is our finalised design:

Problems and solutions

3D Printing

Problem:

It was difficult to visualise and come up with the dimensions of the teeth for the linear rack. 

The rack overall took a long time to print and make as there was a lot of experimentation with the parameters to make the final print. 

Solution:

Make a small sample prototype to experiment and see if the design will work

Make the final design smaller and thinner

Programming

Problem:

The temperature sensor was not working on one Arduino board

Temperature sensor had started overheating despite the correct arrangement

No data came out

Solution:

After a bit of counseling and tryouts we found that the issue stems from the Arduino board and not the sensor itself

Had to only use one Arduino board for our prototype

Integration

Problem:

The supports had too tight a gap to be used for intended use

Original idea was to secure the rack using just 1 support

After testing, there was little to no linear movement with just 1 small support

Solution:

As one support is too small, we had to use different sized supports (scrap from our testing) to clamp the rack

Able to enforce a very smooth linear movement while reusing material

The linear rack is also not inserted in the support as planned

Limitations

Design Flaws 

Stepper motor too weak

Original idea was to use 1 stepper motor and attach the temperature sensor and strainer onto the linear rack

Motor was unable to lift the linear rack more than once

Solution:

Removing the temperature sensor and strainer from the linear rack to put less stress on the stepper motor

Replace the current stepper motor with a 12V stepper motor for more power

Time Management - Many last-minute calls

Although we had followed the timeline we overlooked a few details

Set us back a lot & stressed us out till the end

Solution:

Do team meetings about logistics before any physical creation

Update each other about their workload & fill in gaps

Hypothesis Testing

For this week of blogging, I will be writing about the experience that I obtained from hypothesis testing using full and fractional. The 3 factors used are the Length of the Catapult Arm(A), Start angle(B), Stop angle(C).

Below show the data obtained for Full Factorial: 

The data below show what was obtained for Fractional design:

Brayden will use Run 5 from Fractional Factorial and Run 5 from Full Factorial.

Jolyn will use Run 3 from Fractional Factorial and Run 3 from Full Factorial.

Kalyani will use Run 4 from Fractional Factorial and Run 4 from Full Factorial.

Gideon will use Run 6 from Fractional Factorial and Run 6 from Full Factorial.

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 the different users will not have any effect on the flying distance of the projectile. Flying distance for catapult A and catapult B is collected using the factors below: Arm length =  24.1cm Start angle = 0 degree Stop angle = 90 degree
Step 1: State the statistical Hypotheses:	State the null hypothesis (H0): U1 = U2 There will not be any effect on the distance the projectile can fly State the alternative hypothesis (H1): U1 ≠ U2 There will be an effect on the distance that the projectile can fly
Step 2: Formulate an analysis plan.	The sample size is 8 < 30. Therefore t-test will be used. Since the sign of H1 is ≠, a two-tailed test is used. The 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: Mean: 105.6 Standard deviation: 1.78  State the mean and standard deviation of sample catapult B: Mean: 117.0 Standard deviation: 3.07 Compute the value of the test statistic (t):
Step 4: Make a decision based on the result type	Type of test  Two-tailed test: [ ✓ ]  Critical value tα/2 = ± 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 T = -8.50 Therefore Ho is rejected.
The conclusion that answers the initial question	To conclude, there is an effect on the distance traveled by the projectile based on the calculation made above.
Compare your conclusion with the conclusion from the other team members. What inferences can you make from these comparisons?	By comparison between my conclusion with Kalyani and Jolyn’s conclusion. It is safe to say that H。is rejected hence, the different users have an effect on the flying distance of the projectile.  Out of the many inferences, I will write 2 which I found to be the most interesting. The first inference would be that the different rubber bands have different strengths in tension. Some rubber bands are tighter hence increasing the strength of the catapult while other rubber bands are looser so it has caused the catapult to have less strength. It is difficult to find rubber bands of equal tightness. Another inference was the start angle for the 2 catapults is different. For catapult A, the original start angle is not truly 0० as it is slightly more tilted while catapult B has a normal 0०. Thus, the distance recorded could be affected by these 2 inferences

Reflection:

After learning about hypothesis testing, I realised that it was a concept that is pretty easy to learn but not master. Hence, I knew that I will be revisiting the lesson material when I need. After, the practical and the lesson practice, I can use hypothesis testing for any project that requires this skill

Design of Experiment(DOE)

For this week, I was assigned case 1 for the Design of Experiment. Hence I used Excel to find out how many uncooked kernels are left in the bag. I assign 3 factors according to A being Diameter, B for Microwaving time, and C for Power. 

The table below shows the data provided.

So, to compare the factors in 1 graph, I will need to find the average of High/Low A, B, and C. Thus, the graph below will show the Full Factorial Analysis.

As shown above, the gradient from each line shows how much change. Hence it can be determined that C(Power) has the biggest change in gradient while A(Diameter) has the least change for the gradient.

The tables and graphs below will show the interaction effect between 2 factors. The interaction effect is basically what 1 factor does to the other factor when there are different values. Hence I have done the interaction effect of (AxB),(AxC),(BxC).

In AxB, the gradient for High B is negative while Low B is positive. Hence there is significant interaction between A and B

In AxC, the gradient change is not that huge so there is not a big significant interaction between A and C.

In BxC, both gradients are negative and for one there is a steep gradient. So, there is a big significant interaction between B and C.

For Fractional Factorial Design, I choose the results from runs 2,3,5,8 as there are factors of both - & + equal number of times. This will result in an orthogonal design with good statistical properties

As shown in the graph above.

A(Diameter of the bowl) increased from 10 to 15cm, the mass of the bullets increase from 1.15g to 1.9g.

B(Microwaving time) increases from 4 to 6 minutes, the mass of bullets decreases from 2.1g to 0.95g.

C(Power) increases from 75% to 100%, the mass of bullets decreases from 2.55g to 0.50g.

So, what can be seen from the graph would be that the gradient for Power is the steepest followed by Microwaving time and lastly Diameter. There are similarities between Fraction Factional and Full Factorial so using Fraction Factional is more desirable as fewer runs are done hence, less time and materials are needed to get the same results

When converting Excel to Google Sheets, the file was corrupted so I was only left with the screenshots I took.

3D Printing Adventure

In this week, we are tasked to complete a 3D printing project and make something that cannot be easily made subtractively. What that means is that the model that we make or design should not be able to be made through other means like laser cutting or carving it.

So, the 3D model I was planning to make was something that can meet the requirements so I thought of a design that is similar to the green lantern logo, but that would be too simplistic so I wanted to add a star within the circle of the logo.

This is something like expectation vs reality as what I imagine making was the star is facing the side view in the lantern. After taking about 1-2 hours trying to figure out using Google or asking my friends while experimenting with the different ways to achieve what I had in mind. I gave up knowing that I have to just go with what I made and print it the next day as it was getting quite late and unknowingly spent too much time on this.

So this is the final design in Fusion360

 

This is the STL file using Cura: https://drive.google.com/file/d/1mJaJ-LQJoAjK0H20HVML4rXmod-a9nR9/view?usp=sharing

When I send it to Ultimaker Cura as an STL file and slice the file, I found out that it only took a few minutes which made me realise that the print may not be sturdy enough due the to parameters I set for the model. I decided to print it anyways to get a test print for future references.

In my 2nd print, I decided to increase the infill so to make it more sturdy as the first print broke within a few minutes of me playing around with it. I also tried to tilt the model to be standing vertically for this print as I needed it to so some indication of having supports but it seems that the tilting made the print messed up.

This is the 2nd print with the support.

This is the shot for both the prints. 

Hero Shot:

This is me giving 3D printing a try and I did enjoy myself from the thought process to the actualisation of the print. I am very excited to utilise 3D printing for the best tea maker project after learning about 3D printing. I think that I just need to spend more time experimenting with Fusion360 and Ultimaker Cura to bring out the full potential of 3D printing. I hope that the next time I use 3D printing, I will be more adept at bringing my concepts to life.

PS: I totally did not realise that I did not publish this and only realise it when I need to submit the next blog