0LAUK0 PRE2018 3 Group 13 Dummy sentence: Difference between revisions

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<p>The first part is the braille display. The braille display refers to the way we’re going to display braille. This could be done with either providing a solid plate in which braille is already displayed and simply using that or a mechanisms which display’s the braille. This mechanism could for example be manually pushing the pins to create a braille display. Depending on the depth of which we want to test, there are multiple options to create the braille display.
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== Description ==
 
The dummy sentence is the first physical thing that will be designed. As stated earlier, the dummy sentence was chosen to be made to provide a full sentence in braille, without the product being extremely expensive. The initial plan was to make a prototype in which a full sentence could be displayed on demand. However, the final product will be a static sentence. The reasons for this will be explained in this section.
 
The final dummy could be used to further improve user research, for example by making the dummy out of different materials to test the preferences of the users. It could also be used to try out different positions of relevant buttons and switches.
 
== First ideas ==
 
The initial idea for a dummy sentence was to make a prototype with a predefined sentence, which could be displayed on demand. This way, the idea of a refreshable braille display, in which letters appear and disappear, remains. However, because no electronics are used, the cost of the prototype would be low.
 
With this in mind, the first version of the 3D model was made, which can be seen in the figure below.
 
[[File:Dummy.jpg|centre|500 px]]
 
As can be seen, the idea was to be able to screw this plate to a base below it, where the mechanism would be located to move a sentence up and down through the holes in the display. However, since the plan was to 3D print the model, it was realised that this was not realistic, since the 3D printer would have to print very fine screw thread. Therefore, the dummy was remodelled to be more “3D printer friendly”.
 
[[File:Dummy_V2.jpg|centre|500 px]]
 
== Adding the mechanism ==
 
Now that the general idea was established and the main part of the prototype was modelled, the mechanism to raise and lower the sentence could be added to the design. For this, it had to be decided what sentence would be displayed. Eventually, the Dutch sentence “Ik lees braille.” was chosen, which translates to “I read braille.” in English. The braille equivalent is shown in the figure below.
 
[[File: Ik_lees_braille._.jpg|centre|1000 px]]
 
Since the model had to be kept 3D printer friendly, adding this mechanism came with some difficulties in the modelling of the prototype. Eventually, after several new ideas and models, the design was finished, which can be seen in the figure below.
 
[[File: Dummy_V3.jpg|centre|500 px]]
 
=== Design features ===
There are a lot of things to note in this model. Firstly, the braille sentence, made of pins of different heights. The dots that will be displayed will protrude through the top plate of the prototype. The dots that are not used, have a lower pin instead of no pin at all. This is done to stay as closely to the eventual product as possible, where the pins are always there, just either raised or lowered.
 
The pillars below that to hold up the sentence so that it reaches the top of the prototype. It was chosen to raise the sentence, instead of lowering the total height of the model, to make the assembly easier. The pillars have been added so the sentence can be mounted to the base, without that taking too much material to print. This means that this design is more 3D printer friendly.
 
The whole mechanism of being able to raise or lower the sentence is in the eight holes that can be seen at the bottom of the top plate. Because there are holes on different heights, the top plate can be mounted to the base at two different heights. This equals the sentence being moved up or down, without having a complicated mechanism to go along with it. The functioning of this solution is shown in the figure below, with the first render being in the highest position, while the second render is in the lowest position.
 
<div style="display: inline; width: 1200px; float: right;">
[[File:Dummy_V3_noletters.jpg|550 px]][[File:Dummy_V3_letters.jpg|576 px]] </div>
<br><br>
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<br><br>
<br><br>
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<br><br>
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== 3D printing problems ==
With the model completely finished, while also considering the limitations of 3D printing, the model was ready to be printed. Mister Van Gorp, the skills trainer of the Mechanical Engineering department, was paid a visit to evaluate the design and to print it at the department’s printers. Eventually, the conclusion was drawn that the holes and braille pins were too small to print, so the design would not function. This meant that the whole design had to be remodelled again. Together with mister Van Gorp, a backup plan was made and tested.
=== Backup plan ===
The backup plan that was executed was to implement the pins into the top plate, and therefore have a completely static prototype instead of having two different positions of the pins. To try if this did work, because the pins would still have a tiny diameter, a test sample was printed to see if this plan would work.
Since the orientation of the print made a big difference, after the first test had failed, other orientations were tried. The results are shown in the figure below. The left sample is printed as it was modelled, the middle sample is printed upside-down and the right sample is printed on its side.


The first option is to create a very basic braille display dummy. This dummy would be similar to a solid plate, which contains braille, and could be attached on top of the casing of the robot. This form of braille display will be relatively simply and will ignore the user preferences for material types or other preferences such as a button and focus more on main interactions. These interactions will be purely based on what they think of the idea and what they would improve. This option would be sufficient in case you want to verify the intent of your product. In case you want to test multiple things such as user preferences for example materials or buttons, this option might be insufficient. On another note, this option might be sufficient as a base dummy in which you can extent later on. For example it might be possible attach the materials which you wish to test into the basic braille display or to create buttons at the end of the display. However, depending on the design of the display, extensions might have a low quality.
[[File: Testsamples.jpeg|centre|500 px]]
<br><br>


The second option for the braille display would be to design a display similar to the previous one, but instead design it with these extensions already included. In other words, a braille display consisting of a  to-be-tested material which contains braille which is changeable. This could be done in either two ways. The first one would be to create a display on which the materials can be attached upon in such a way that the readability of the display is sufficient. This method would allow for easier testing since both materials could easily be changed and it allows for reusability of the braille display. The main problem with this method would be the technical problem, in which you have to create a mechanism with a loosely coupled material who ensures sufficient readability. The main problem with the readability would be the that the material would simply be pushed up completely by the braille pins since it’s loosely attached. This problem would could be solved by making the material more attached to the braille display, however this method might then lose its purpose depending on how tight the attachment is.<br>
It is easy to see that printing it on the side gives the best result. Therefore, the whole model was printed on its side which resulted in the final prototype as can be seen in the figure below.
The second method to achieve this option would be to create the multiple displays in which the to-be-tested material are integrated. In these displays, the materials would be strongly attached to the display. This method does not suffer from the problems that the previous method does. This method instead uses more materials, as multiple displays have to be created. Additionally, due to the aforementioned reasons, the reusability of the display is lower.
<br><br>


The dummy is 3D printed to have a physical product. The top part of this is already finished, which is shown in the figure below.
[[File: Dummy_V5_printed.jpg|centre|800 px]]
[[File:Dummy_top.jpeg]]
</p>

Latest revision as of 12:11, 4 April 2019

Description

The dummy sentence is the first physical thing that will be designed. As stated earlier, the dummy sentence was chosen to be made to provide a full sentence in braille, without the product being extremely expensive. The initial plan was to make a prototype in which a full sentence could be displayed on demand. However, the final product will be a static sentence. The reasons for this will be explained in this section.

The final dummy could be used to further improve user research, for example by making the dummy out of different materials to test the preferences of the users. It could also be used to try out different positions of relevant buttons and switches.

First ideas

The initial idea for a dummy sentence was to make a prototype with a predefined sentence, which could be displayed on demand. This way, the idea of a refreshable braille display, in which letters appear and disappear, remains. However, because no electronics are used, the cost of the prototype would be low.

With this in mind, the first version of the 3D model was made, which can be seen in the figure below.

Dummy.jpg

As can be seen, the idea was to be able to screw this plate to a base below it, where the mechanism would be located to move a sentence up and down through the holes in the display. However, since the plan was to 3D print the model, it was realised that this was not realistic, since the 3D printer would have to print very fine screw thread. Therefore, the dummy was remodelled to be more “3D printer friendly”.

Dummy V2.jpg

Adding the mechanism

Now that the general idea was established and the main part of the prototype was modelled, the mechanism to raise and lower the sentence could be added to the design. For this, it had to be decided what sentence would be displayed. Eventually, the Dutch sentence “Ik lees braille.” was chosen, which translates to “I read braille.” in English. The braille equivalent is shown in the figure below.

Ik lees braille. .jpg

Since the model had to be kept 3D printer friendly, adding this mechanism came with some difficulties in the modelling of the prototype. Eventually, after several new ideas and models, the design was finished, which can be seen in the figure below.

Dummy V3.jpg


Design features

There are a lot of things to note in this model. Firstly, the braille sentence, made of pins of different heights. The dots that will be displayed will protrude through the top plate of the prototype. The dots that are not used, have a lower pin instead of no pin at all. This is done to stay as closely to the eventual product as possible, where the pins are always there, just either raised or lowered.

The pillars below that to hold up the sentence so that it reaches the top of the prototype. It was chosen to raise the sentence, instead of lowering the total height of the model, to make the assembly easier. The pillars have been added so the sentence can be mounted to the base, without that taking too much material to print. This means that this design is more 3D printer friendly.

The whole mechanism of being able to raise or lower the sentence is in the eight holes that can be seen at the bottom of the top plate. Because there are holes on different heights, the top plate can be mounted to the base at two different heights. This equals the sentence being moved up or down, without having a complicated mechanism to go along with it. The functioning of this solution is shown in the figure below, with the first render being in the highest position, while the second render is in the lowest position.

Dummy V3 noletters.jpgDummy V3 letters.jpg























3D printing problems

With the model completely finished, while also considering the limitations of 3D printing, the model was ready to be printed. Mister Van Gorp, the skills trainer of the Mechanical Engineering department, was paid a visit to evaluate the design and to print it at the department’s printers. Eventually, the conclusion was drawn that the holes and braille pins were too small to print, so the design would not function. This meant that the whole design had to be remodelled again. Together with mister Van Gorp, a backup plan was made and tested.

Backup plan

The backup plan that was executed was to implement the pins into the top plate, and therefore have a completely static prototype instead of having two different positions of the pins. To try if this did work, because the pins would still have a tiny diameter, a test sample was printed to see if this plan would work.

Since the orientation of the print made a big difference, after the first test had failed, other orientations were tried. The results are shown in the figure below. The left sample is printed as it was modelled, the middle sample is printed upside-down and the right sample is printed on its side.

Testsamples.jpeg

It is easy to see that printing it on the side gives the best result. Therefore, the whole model was printed on its side which resulted in the final prototype as can be seen in the figure below.

Dummy V5 printed.jpg