Concept¶
The idea is to build a remote control that will the embedded device. The remote control will be small and will be mounted on a cane that is used to assist visually impaired people.
The user of this device is anyone, but above all this equipment is designed for visually impaired people.
The product of the physical design is the production of an actual small remote controller, which will be designed to be mounted on a cane for the visually impaired. It will have a total of five buttons. The first four buttons will be numbered in Braille and the fifth will be the largest and will be used for voice assistance.
Case¶
The 3D print visualization for our remote control will be created in SketchUp software. All files can be found here:
Design¶
In the picture below you can see a sketch of the dimensions of the remote controller. The related user story is:
As a user, I would like to have enough space between the buttons so that I can feel the difference between the buttons.
As a user, I would like to have the number one written in braille on the first button so that I can feel what button I am pressing without needing to see it.
Here you can see the button that contains the number one written in braille. For more information about Braille, see Physical Design - Research.
As a user, I would like to have the number two written in braille on the second button so that I can feel what button I am pressing without needing to see it.
Here you can see the button that contains the number two written in braille. For more information about Braille, see Physical Design - Research.
As a user, I would like to have the number three written in braille on the third button so that I can feel what button I am pressing without needing to see it.
Here you can see the button that contains the number three written in braille. For more information about Braille, see Physical Design - Research.
As a user, I would like to have the number four written in braille on the fourth button so that I can feel what button I am pressing without needing to see it.
Here you can see the button that contains the number four written in braille. For more information about Braille, see Physical Design - Research.
As a user, I would like to have a big button (the size of 2 buttons) that connects me to the voice assistant so that I can ask questions.
After the first failed attempt at 3D printing the casing, I found that I needed to make the holes bigger. So I increased all the dimensions of the part for the buttons by 5 mm. Thus, the dimensions for the first four button holes are: 13,50 mm x 13,50 mm. And the dimension for the hole for the voice assistant button is 18.50 mm x 18.50 mm.
As a user, I want to be able to plug a cable into the ESP32 through the case so that I can power the remote.
This picture of the implemented case in Sketchup shows the opening for the USB C port, which corresponds to the width of our USB cables.
Here you can see the result of our 3D printed model:
As a user, I would like my remote to have a max thickness of 5cm to make it easy to mount to my cane.
As a user, I would like to have a slim design using the PCB so the overall size of the case can be smaller.
As a user, I would like to have enough space between the buttons so that I can feel the difference between the buttons.
Below you can see the complete model, split into two parts for 3D printing, of our remote control created in SketchUp. The minimum thickness of our remote control will be 0.2 cm. You can also see the dimensions in the pictures below. Related to this are the user stories that are mentioned above this text.
Here you can see the whole part of the controller without the top part:
Here you can see the model area in detail, where there is a post on each corner that will hold the top of the remote controller:
Here you can see the top of the remote controller:
Here you can see another part with the same dimensions as the top part. Only this part is without button holes and will serve as the bottom side of the casing:
Digital manufacturing¶
We decided to print our physical design in a 3D printer. The main reason is that we are designing a remote control that will be mounted on a stick. I think the design may be too complex to create using a laser cutter, so we prefer to use a 3D printer. The controller design, as shown in the 3D models in SketchUp software, shows the controller with the projected buttons displayed in Braille. These notches I think the 3D printer can handle more easily than me learning to use a laser cutter and doing it properly by hand. However, I have never used 3D printing and this will be my first product made from a 3D printer.
After the 3D model was accurately measured and correctly completed, I started printing. The first thing I had to do was download the Cura software, which is made by Ultimaker, where I inserted my 3D model in the STL file. It uses a language called “G-code” that can be transferred to other printers. Then I edited it, prepared it for printing on the Ender 3 printer.
Firstly I divided my model for printing into two parts: top and bottom. The top part took an hour and a half to print. And the bottom part took 2 hours and 42 minutes. But after discovering that the bottom main part didn’t print out all the way. I had to cut the columns in each corner and print a new part, exactly the same dimensions as the top part, but without the button holes. Anyway, that part also took an hour and a half.
Here you can see the prepared top in Ultimaker Cura and on the bottom left is the estimated duration.
Material¶
As a user, I would like the material the remote is made of to be an inexpensive material, so it is affordable to me.
I used PLA material. This material should be stiff and strong. It is also becoming more and more common filament for 3D printing. It’s probably user friendly because it has a low melting point. PLA can be used in both Ultimaker and Prusa printers, because the filament does not require a heated bed.
Printing¶
Here you can see the 3D printing process of our remote controller.
For the first 5 to 10 minutes or so, it’s a good idea to wait to see what the first layers of the print look like so you can just check that everything is correct and the print will be fine. You can see the first layers in the picture below:
The next photo is from the printing process:
Here in the third picture in the “printing” section you can see the correct and finished top part of our remote controller:
Here you can see the beginning of the printing of the bottom of the casing:
Here you can see the bottom printed part, which was not printed in complete form:
Failures¶
I somehow overlooked the information that for 3D printing the model should be created in millimeters and not centimeters. So I had to redo my finished model in centimeters all over again in millimeters. Fortunately, I’ll remember that now. This is what it looked like the first time in centimeters:
When I inserted the STL file into the Ultimaker Cura software, I found, because of the red marking, that there were two errors. At the same time, the STL file was fine. However, I tried to edit the model again in SketchUp and fortunately it was successful and after that it didn’t find any errors. In the image below you can see the red highlighted bugs in Ultimaker Cura:
After the first printout of the bottom part, I found that the bottom part didn’t print completely. So I had to come up with an idea to fix it. I had two choices:
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The first option was to rebuild the model in Sketchup, because obviously there was some mistake and the very bottom part didn’t show up in UltimakerCura.
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The second option was to cut the corner posts on each side from the bottom and print only the top part again, but without the button holes. So that the newly printed part would fit nicely into the cover and hold just as well as the top part of the casing.
I decided to choose the second option, which was definitely less time taking for me than starting to modelling again.
Here you can see another failure. When I had the idea to cut the column on each corner, because of the missing background, I didn’t realize that this would make my accurately measured model smaller and the PCB wouldn’t fit in the housing:
