Prototype¶
A quick description of a drawbot is a robot that can write simple programming language as python,C/C++ or java scripts
to generate two-dimensional graphics.
The builtin graphics contains rectangles, ovals, paths, polygons, text objects and transparency.
The drawbot is mostly an ideal tool to teach the basics of programming. Children that use the drawbot get graphical
feedback via coding.
With this they can start understanding programming concepts such as variables, conditional statements, functions.
The prototype of the drawbot is simply made of 3D printed materials and two stepper motors with a servo motor connected to the pcb and Wemos.
Drawbot models¶
The drawbot prototype is split in four 3D printed components the models are the .stl files that would be reference in this documentation. The 3D models are meant to be put together as a whole functioning product.
Disk model¶
This disk will be the platform where the drawbot draws its drawings on a flat surface that spins round and round. A standard quality print with 10% infill takes 5 hours and 38 minutes to print according to Cura.
Measurements regarding the drawing surface disk of the prototype print
- Disk diameter = 16 cm- Disk height = 0,5 cm
- Stepper motor attachment hole: - Attachment ring height = 1 cm - Depth = 6 mm
- Length = 4,92 mm
- Width = 2,92 mm
Pen ring model¶
The pen ring model is the holder for the pen that will be moved by the servo motor. It is used to move the pen on and off the drawing platform. A standard quality print with 10% infill takes 24 minutes to print according to Cura.
Measurements regarding the pen attachment of the prototype print
- Ring outer diameter = 2,5 cm- Ring inner diameter = 1,5 cm
- Ring height = 1,5 cm
- Screw hole diameter = 5 mm
Stepper arm model¶
The arm model is use for holding the pen in place while drawing. It’s purpose is to move the pen accurate over the drawing platform. A standard quality print with 10% infill takes 2 hours and 2 minutes to print according to Cura.
Measurements regarding the arm of the prototype print
- Length = 15,1 cm- Width = 3,2 cm
- Pen hole diameter = 1,5 cm
- Stepper motor attachment hole: - Depth = 6 mm
- Length = 4,92 mm
- Width = 2,92 mm
drawbot stand model¶
The stand is mainly the model that holds everything in place and basically completes the product as a whole. It is the
biggest of all four models.
A standard quality print with 10% infill takes 7 hours and 57 minutes to print according to Cura.
Reference.model.drawbot_stand
Measurements regarding the base of the prototype print
- Stand: - Left tower height = 8 cm- Right tower height = 3 cm
- Width = 7 cm
- Length = 18 cm
- Towers width = 5 cm
- Towers length = 5 cm
- Stepper Motor: - Mount hole length = 3,1 cm
- Mount hole width = 2,9 cm
- Mount hole depth = 1,5 cm
- Height = 2,9 cm
- Mount height = 1,9 cm
- Arm height = 2,2 cm
- Mount height for arm = 1,9cm
3D print material¶
PLA filament is used to create 3D-designed products and is the most recognizable material in every 3D printer. The PLA material is easy to get and can be used by anyone With a 3D printer with no issue. because of that is the cost of PLA filament at the cheap side of the market. The PLA is very easy to process by the printer because of its light flexible material. So the PLA filament is overall the best material to use for printing. For more information check the PLA source URL under the text.
Model errors¶
This are the user stories involving the discovered problem during the procces of creating the Draw-bot.
- As a user, I want a stable platform that the drawbot can draw on, because with an unstable platform I can’t draw consistent lines.
- As a developer, I want materials that combats and isolate the heat of the stepper motor, because the stepper motors will melt/heat up the 3d model after a while.
- As a user, I want more physical support by the stepper arm, because the stepper arm weakens after a while.
Model versions¶
During the draw-bot project, there will be always a different version of the draw-bot. With a minor tweak to the model itself or sometimes a whole re-model of the design itself. With this, we want to show the process design of the draw-bot from the beginning to the end. It’s a way to show that there is always progress in the design idea that’s coming closer with each version to the final product. Down below you will see the different versions of the draw-bot that was created in this project.
Version 1¶
The first version is specifically designed to house the two stepper motors in a fixed position. It was also in the project description of making a machine with those specific components build in. The first iteration was deciding which method of drawing would be best to build for kids. There were two methods a polar coordinate system and a cartesian coordinate system. The polar method was the best because it was easier to build for kids than building a cartesian Draw-bot.
The cartesian design would be too complex to build by kids. The design exists out of a stand that holds the two stepper motors in place with one stepper motor higher than the other. The reason is for the pen to be held in place with an arm to move the pen over the platform. The design was meant to resemble a record player for drawing shapes based on the two steppermoter’s steps.
Version 2¶
The second version is created to give the Stepper motor to adjust the position with the help of popsicle sticks. The idea of popsicle sticks came into play when the client was speaking of something children would often fidget with. The client wanted the product to become more child friendly so there was less plastic for fewer printing hours. The first version had an issue with the stepper motor getting too hot nearby the 3d material started to heat up and weaken. So for that choice, I thought of having four pillars for each motor to hold in place.
The popsicle was used in a way to hold the motor airborne. So in case, the motor gets hot the 3d material won’t have a direct touch on the motor. It is a way to prevent the 3d materials from weakening. The client Also wanted the motor to be adjusted in the position for better range. So I chose the popsicle as a way to move the position of the motor.
Version 3¶
The third version is designed to adjust the Stepper motor and the Stand itself with the help of popsicle sticks. After the second version, the client wanted less plastic and more popsicle connection. So I decided to cut the stand and made sure that popsicles could be used to connect the two. It was the client’s request to have more rangs to draw. The stand with the popsicle was a way to extend the range of the stand so that it can be adjusted anytime.
Version 4¶
The fourth version is designed to be half popsicle and half 3D material. It was more so to adjust any part of the design with popsicles. The client wanted a design that can compare to lego. So I choose to make and print two stepper motors holders that can connect with a popsicle. The problem with the stepper motor getting too hot was solved instead of hot it was warm. The 3D material was able to handle that kind of temperature more so that was not the issue anymore. Also because the third version with pillars was not stable to hold the disk and the stepper arm in place. The pillars on is own were not strong and could break off easily if not watched carefully.
So It was decided to create support on the stepper motor holders to help with stabilizing the disk and arm. To hold everything in place for the two holders a beam was created that can insert the popsicles in the beam and connect with the stepper motor holders. At first, I thought to use a connector joint to connect all, but the connector joint was not good enough to hold the drawbot in place. For the arm, I used three popsicles to re-enforce the arm for a more stable drawing, but also to use and adjust the length of the arm. The client requested that the drawbot be designed in a way to be more adjustable than before.
The popsicle is self can be cut to suit a certain length that the user desires and that is what the client wanted to have the freedom to adjust it yourself. In a way, the design is more child friendly and can be used as a building kit to create your very own drawbot.
