NOTE: Images can be expanded by clicking on them
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Welcome to the skill learning page. This page is a collection of work on skills that I wanted to improve upon or learn. This page contains:
- cost model/costing comparison
- concept drawings and practice
- line work and shadow practice
- electronics workshop
- plasma cutter workshop
- wind tunnel workshop
- what I want to improve on and learnin the future
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Cost model/ Costing comparison
One of the skills I decided I would learn more about is making a cost model and comparing the costs with others. This was mainly to help to compare existing talking colour detectors with my own designed colour detector for the blind sensor aid project. In the past, my cost models would be very basic and would not cover everything. Also the layout was very messy so I needed to learn a way of making cost models which was more informative and overall better.
To do this I used the book Product Design and Development Seventh Edition by Steven D. Eppinger. In this book on page 11o and page 111 there is a section on developing a cost model of a product. I used this to create a practice cost model. Here is an image of the cost model I made:
Here I applied the same format but added a section at the bottom so that I could compare the prices. For this practice, I only filled the graph with the components that I brought to build. For the proper one on the blind sensor aid project page, I have also added more parts. This includes the casing of the device, electricity used to make and I have also added a part for if someone was hired to construct and input the code onto the device.
By using this book I have learnt how to produce a cost model which is accurate, neat and is one that can provide a lot of information.
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Concept drawings and practise
To improve my skills I wanted to work on my concepts. Previously they would just be quick sketches without any description. To improve them and make them better I made a practise concept which included a title, labels, shading, accuracy (using tools inside to produce accurate lines), and colour. Here is a photo of the practise concept that I made:
I also worked on my shadows so that I could implement this as well. Other features that I will implement on proper concepts is more draws showing how the device is to be used. This can be as simple as a drawing of a hand. This is also good because it gives the viewer a sense of scale. Here is a photo of the shadows and cubes I practised:
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Line work practice and shadow practice
To improve on my concept drawing skills I decided to use Montague J. book on perspective drawing to practise shadows and line work. There are three types of lines that I have been practising which are used in different places on a sketch. To practice the line work I used Boldmere fine liners in sizes 0.03mm, 0.5mm and 1mm pen tips:
To begin with, I started by drawing some 3d shapes in a two point perspective view. Once this was complete I moved on and started with the 0.5mm fine liner. This was for the outside lines and would be of a medium thickness compared to the other lines. Montague J. book shows that the outside lines should be thick but not as thin as the inside lines and not as thick as bottom lines or lines which are in contact with a surface. I chose to use the 0.5mm line finer because I felt it produced the best line out of the set I have. Here are some photos of the outside line work I did:
Once this was completed I moved onto the second type of line, the bottom lines. For these lines they should be thicker than all the other lines on a sketch because they are in contact with a surface. For this I used the 1mm fine liner, I like to go over the line twice to make it even thicker. Sometimes when you just draw the line once, it can seem very hard to see the difference in the line. Also I felt as though it looked more appealing. Here are the drawings with the bottom line:
The next step was to add the final type of line: the inside lines. These lines should be the thinnest of all the lines and for this I used the smallest fine liner that I had which was 0.03mm. An issue I had with this fine liner was that no matter how I used it, it would always seem quite similar to the outside lines in terms of thickness. If I were to add shading or colour I would probably remove these lines entirely as the edges of the shape can be seen on the borders of the different shaded areas. Below are the drawings with the inside lines:
From this line work and the use of Montague J. book I have learnt how to apply different types of lines to a sketch properly. I can further improve by adjusting the thickness of the lines and potentially removing the inside lines dependant on the type of drawing and what other features are involved such as colour and shading.
I decided for these drawings that I wasn’t going to include colour. I thought having dashed sections would look better and I wanted to practice this and some shadows. Having a background colour may have also made it look a bit messy and not as appealing. I decided to add dashed lines to the drawings on the surfaces that were furthest from the light source as these are meant to be the darkest faces.
I also decided to draw the outlines of the shadow. I did this by making a point on the horizon line and drawing lines to this point from the corners that are touching the floor/corners that are on the bottom lines. From here I then made another point vertically above the point on the horizon line and drew lines from this point to the top corners above the corners that were marked. This created intersection points which made up the outline of the shadow. For this I used the 0.5mm fine liner. Here are the drawings with the dashed lines and the outline of the shadowed areas:
Once this was completed all I had to do was fill in the shadows. I decided not to give one of the drawings shadows to see a comparison between a drawing with a shadow and one without. To fill in the shadows I used NOVA dual-tip designer markers. These are alcohol based markers for colouring. For the shadows I used the blackest markers that I had.
If I wanted to make the shadows realistic, I could have drawn a background, something like bricks or grass, and draw this area quite dark but not as dark as a solid black. Below is photos of the drawings with the shadows:
What I have learnt
I have learnt how to use shadows and different lines on a drawing. I wanted to learn this because it would help improve my drawings and concepts, making them stand out more. I decided to learn the line work because I wanted to add more detail to my drawings as my sketches prior to this were one constant line using a pencil. This was okay but it meant that concepts and sketches that I drew up were different to see and seemed quite boring. By learning how to draw and use different lines with a fine liner, my concepts have been much clearer and easier to understand. I intended on using this skill in all my concepts and sketches going forward.
I wanted to learn how to draw shadows as this would help make my drawings look even better and more realistic. In the past I typically would using shading to show where the light would come from. This was good as it helps make the drawing look solid but they wouldn’t look that realistic. Because of this I learnt how to draw shadows. I needed to do this so that I could draw them correctly, with the correct shaping. Going forward, I want to combine all these different aspects to make realistic and well drawn concepts. I also want to be able to manage the different aspects correctly so that there isn’t too much and it looks good. I will continue to develop these skills by practicing and reading more into the topic.
References for improving concept drawing and sketch practice
Allen J. (2007) Drawing Geometry A Primer of Basic Forms for Artists, Designers and Architects. Edinburgh, Floris Books.
Allen J. (2012) Making Geometry Exploring Three-Dimensional Forms. Edinburgh, Floris Books.
Montague J. (2010) Basic Perspective Drawing A Visual Approach. Fifth Edition. New Jersey, John Wiley & Sons.
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Here are some other drawings that I produced:
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Electronics workshop
In the electronics workshop I recapped about some parts of electronic circuits and the machinery and tools used. I also learnt how to solder circuits onto PCB boards. These skills were then used to make a function moisture sensor. Here is a photo of the moisture sensor that was built:
I was then put into a group where our task was to produce a webpage about the multi-meter device. This webpage would then be used to help younger students learn about the device, how to use it and learn what it can be used for. Here is the link to the webpage we produced:
https://blogs.brighton.ac.uk/eelabs/multimeter
My contribution to this task was the video on how to operate the device and identifying the different buttons. This webpage was designed to be a multi-meter guide package which people could use. I worked on this package with Scott and Sam of which Scott made a diagram of the tool.
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Plasma cutter workshop
For this workshop and induction I was shown how the plasma cutter operates. This was then used to produced a small box using the bending machine and a mallet. Below is a photo of the box that was produced.
The plasma cutter works off of a CAD drawing file that has been exported to a DXF file. This system also used G-code to guide the tool to cut the desired shape. the plasma cutter works on three axis and is used to cutter metal sheets whereas a laser cutter is used for softer materials such as MDF, plastics and others. Once the metal sheet had been cut out, they were then dipped in water. This was to cool them off because the plasma produces lots of heat. I was then tasked with forming it into a box. The first two sides where shaped using the blending machine and the others had to be bent using a mallet. This was because the previous bend prevented the bending machine from being used properly and the box would have become deformed.
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Wind tunnel workshop
In this workshop, I learnt how to operate the wind tunnel and I performed an experiment. This was then used to produce some sets of data and graphs showing what shape was the most aerodynamic. The wind tunnel was used to measure the horizontal drag.
Below are some photos of the different models and calibrations that were used for the tests:
Bullet model, flat-faced cylinder model and steel ball model photos
Golf ball model, load cell and bracket photos
The thermometer on the barometer measured 21 degrees Celsius at the time of testing.
The barometric pressure (air pressure) was 171.0 mm of mercury.
The wind tunnel can work in both directions and this can impact the measurements. If the wind travels from right to left, the drag forces that is read will read negatives and vice versa. For this experiment the wind was moving in this direction and because of this the lowest value out of the tests represented the highest drag force.
A 3 kilo load cell, a 12V power supply, an anemometer (used to measure the speed of the wind in m/s) and a multimeter was used in these experiments. The multimeter was calibrated so that instead of measuring volts it would measure newtons.
For each test results results were taken at 0 RPM to 800 RPM in increment of 200 RPM.
First tests
The first models that were tested was the flat-faced cylinder model and the bullet shaped model. Below are the results that were produced:
Once these models had been test, it was decided that the bracket that held the models, was to be tested by itself. This was so that later, when the results had all been gather, it could be subtracted to obtain the true values of the model’s drag force. Below are the results of the bracket and a mean result which was used to obtain the true values:
Next, the bracket was removed and the load cell itself was test. This had to be done so that the true values could be calculated to the steel ball and golf ball tests since as they would not use the bracket. Here are the results for the load cell:
From here, the test moved onto testing the steel ball and the golf ball. This was to see whether a golf ball was more aerodynamic than a standard smooth ball. Below are the results of the steel ball and the golf ball:
With the completion of the steel ball and golf ball tests, all the wind tunnel test were complete. Next was to complete the calculations and tables to find the true values and produce some graphs to see which is the most aerodynamic. Below are some tables that were produced to find the true drag force of the balls and the models:
Below are the graphs that were produced and here is a download link to the excel document that was produced:
Click Here: Iain Griffin Wind tunnel results
Reynolds number:
To calculate Reynolds number we use this formula:
Reynolds number can also be calculated using:
images from: https://www.engineeringtoolbox.com/reynolds-number-d_237.html
For these wind tunnel tests, the last formula was used.
u is the flow velocity (m/s) of the for the model.
L is the length of the model
V is the kinematic viscosity
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What I want to improve on and learn in the future
In the future I would like to learn and improve my skills in manufacturing and making items. In the past I have had knowledge and training in different machinery but have never really used them. I would like to learn more about the machines and how I can use them in projects in the future. This would help broaden my knowledge and would improve the items that I make. This could improve the quality and my accuracy and it could help the product function better than they did before. I would also like to learn a bit in how mechanism work and mechanical movements such as gearing, pulleys and others. I have a book by Henry T. Brown on these covering lots of areas such as Pin-wheel escapement, water wheels, scroll gears and many more mechanisms that appear everyday. Learning this could optimise my designs more and overall improve my knowledge in this area.
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