53399 Creative Soft Robotics

Project Objectives

The objective of this project was to utilize soft materials and a material class called “auxetics” to demonstrate the ways that shape and form can create unexpected actions and reactions. These metamaterials, so called due to their properties depending on their shape as well as the material they are made of, have a negative poissons ratio, which means they expand in two dimensions under a single axis load. Compared to traditional materials, this creates an unexpected and visually distinct effect that gets the viewer thinking more about shape and motion.

Creative Design Opportunities

Fabricating our auxetic designs using silicone materials allowed us to test the designs from established literature and modify them. The iterative process enabled us to test these structures at different scales, thicknesses, and densities to create the most dynamic and interesting patterns when applying tension. To avoid unnecessary work, we used the built-in stress simulation in Solidworks to make educated predictions on how the material will behave. The silicone fabrication process verified the relative accuracy of the simulation, which reduced our iterative workload significantly.

Not only does the fabrication process validate our assumptions, but it also allows us to modify and experiment with the current iteration. Using Rhino Grasshopper, we transformed and wrapped the grid-like design. However, the simulation was unable to manage the complexity of the form. Therefore, we had to cast and test the silicone with our hands.

Overall, the soft technologies and the fabrication process allowed us to iterate, improve, and realize our designs.

Process

Research

Our first step was to find past designs that had been proven to work. A deep dive into literature allowed us to find 4 main categories that we ended up modeling and testing. Each of these had distinct visual and motion properties, which we were only able to find out by running FEAs on the designs that we made. Further research allowed us to refine our designs, both by reviewing literature and by validating new designs. This allowed up to pare down the options to a few final designs that we would end up presenting. Our aim was to find unique angles on these auxetic designs by changing parameters, such as taking away links or distorting the mesh. Our continued testing process allowed us to create the most interesting effects on our final designs.

Digital

We used Rhino to create some of the existing auxetic designs from the previous research literature to design the 3D-print mold. This process was relatively quick and straightforward; however, we encountered the most difficulty transforming a design in Grasshopper.

Garth gave us the idea of adjusting an existing design, usually in a grid-like pattern, to see the outcome of such a transformation. This suggestion led to us developing a complex parametric Grasshopper script that uses attractor points and parameter controls. We could modify an existing pattern into two new patterns: expansion and contraction. However, due to issues with the scale and sizing of components, the contraction iteration could not be displayed at the final critique on April 26th.

Physical

As previously stated in Creative Design Process, casting silicone allowed us to verify our simulation results and test for new designs, but it also helped us to fine-tune the thickness and density of our designs. In our earliest iteration, we used one of the softer mixes of silicone, which resulted in the mesh failing structurally and breaking. Learning from our poor choice of materials, we opted for the stronger mix of silicone, which worked out great in the end. The stronger mix allowed us to apply more stress pressure on our mesh and realize its full structural potential.

Outcomes

The final three designs we chose were a uniform auxetic, a mesh of hexagons and auxetic combined, and one curved auxetic that was warped using an attractor point. These provided an interesting sequence of behaviors: the uniform introduces what an auxetic is, the combined contrasts that with an expected and known material, and the warp provides distinct and new interaction.

To house these meshes, we designed frames that served three main purposes. The first was to provide a solid way for the viewer to interact with the pieces. The frames had handles on them that attached to the meshes, allowing for distortion in a controlled, planned manner. The second purpose was to allow for a reference point that would show how much the mesh distorts. Being housed in a constant area while the form expands draws attention to how the shape of the mesh changes. The final purpose of the frame was to provide a way to lift the mesh off the table, which allowed for lighting effects. Since these meshes are very distinct in their shapes, we wanted to highlight how they interacted with light. We decided that shadow effects would be most interesting, and set up two above spotlights to create unique shadow effects under the frames.

Throughout the process, we learned that we should have tested our models physically more, rather than relying on the FEA for the designs. Having more physical models would have allowed us to develop more interesting shapes and behaviors. We also learned to focus more on the true purpose of the project. During each step, we tended to lose sight of the big picture, and instead focused on applications. We were guided to be more pragmatic and think about how each decision impacted the artistry of the piece, rather than trying to rush for an interesting application.

However, this project was certainly a success by our own standards. We were able to create really interesting and unexpected behaviors from our auxetic meshes. We succeeded in our purpose of making surprising and pleasing deformation, and the hands on aspect of the final designs helped in this effect. The viewers during the final presentation were really taken by surprise with the behavior of these meshes, which is exactly what we hoped for.

Video & Images

Citations & Supplemental Materials

Mizzi, Luke, et al. “Auxetic Metamaterials Exhibiting Giant Negative Poisson’s Ratios.” Physica Status Solidi (RRL) – Rapid Research Letters, vol. 9, no. 7, 2015, pp. 425–430., https://doi.org/10.1002/pssr.201510178.

Ren, Xin, et al. “Auxetic Metamaterials and Structures: A Review.” Smart Materials and Structures, vol. 27, no. 2, 2018, p. 023001., https://doi.org/10.1088/1361-665x/aaa61c.

Pan, Qi, et al. “Programmable Soft Bending Actuators with Auxetic Metamaterials.” Science China Technological Sciences, vol. 63, no. 12, 2020, pp. 2518–2526., https://doi.org/10.1007/s11431-020-1741-2.

Grasshopper Script:

https://drive.google.com/file/d/17Q0tD4kFrwGaWCBIePoLLMq2cEud6FP1/view?usp=sharing

Final Product & Frame Designs:

https://drive.google.com/file/d/1mG3Nu2QUIlcHzCPTOhHCXspGPzkfqKoY/view?usp=sharing

Contributions

Dunn: 3D printing molds, final mesh casting, frame design, frame cutting and assembly, Rhino modelling, attractor point setup

Elliot: Literature review, design selection, auxetic casting, frame cutting and assembly, FEA simulations, lighting and presentation setup, model cad for some meshes

The Development of Bow.

Project Overview:

Bow. is an interactive silicone robotic display. The display utilizes a camera to detect a user’s hand (wave) and, when a hand is present, reacts to the user. The display’s reaction is a mix between a wave and a bow.

Project Objectives:

The objective of our project was to create a finger-like pneumatically actuated silicone finger. Our immediate goal was to create a part which, when inflated via an air pump, bent in a way which mirrored a human finger. The loftier goal, which we were unable to complete during the duration of the course, was to develop the part so that it could attach itself to a user’s hand similarly to a brace or exoskeleton. In developing this part, we aimed to further our understanding of cavity geometry, specifically how it affected the inflation and actuation of a soft robotic part.

Creative Design Reflection:

The use of silicone in casting our part allowed us to mirror the fluidity and softness of a real finger’s movement. Additionally, with regard to the concept of attaching it to the user’s hand, we liked the fact that, although the part’s actuation would guide the user’s movement, the softness of the material would allow for the user to pushback/reject movements with far less strain than would be required to pushback against a hard exoskeleton.

In the end, we really enjoyed the fact that, although we did not attach the part to users’ hands, the softness of the material enabled far more user interaction than a harder material would have. At multiple times during the show, we witnessed users poking, prodding, and physically interacting with the parts. Being able to poke them — both while inflated and not — and watch their gelatinous recoil ended up being a fan favorite of those who came by our piece; while this was not intended, it added to the display greatly by allowing physical interaction, rather than only being able to engage through a computer screen.

Lastly, the use of soft technology added a shock-factor and intrigue to our display. When the piece inflates, two air pockets very obviously grow. Because of the softness of the material we used, these pockets seemingly came out of nowhere (as opposed to say, a balloon which is visually limp and deflated). Before engaging with our display, users weren’t quite able to tell what the movement of the part was going to be due to the parts’ opaqueness/translucency, so when the inflation and air pockets came seemingly out of nowhere, they were further enthralled.

Outcomes:

Successes

1. We were able to trial many different cavity designs and settle on both a shape and size (relative to the length and width of the part) which best achieved the inflation angle we desired
2. We designed, fabricated, and programmed an Arduino circuit which used computer vision input to control air pumps
3. We created an interactive display showcasing our research and creative display design.

Failures

1. We were unable to iterate on our design so that the user would be able to wear our part to undergo guided movement. We prototyped multiple different designs for this concept but did not get them to a showcase-able state in time for Rubbery Things.
2. We aimed to have a more complicated script which took into account specific user gestures to control the piece in a more complex way. Due to fabrication timing as well as the limitations of OpenCV via a serial bus, we were unable to update the motor state as rapidly as this goal would require to prevent popping the piece.
3. Although we were able to work around the issue by using an Arduino, we were not able to get a Raspberry Pi Pico to successfully trigger the motors. We’re still not sure why this failed, but were luckily able to switch gears and re-adapt our code to utilize an Arduino shortly before the show.

Technical Documentation

CAD Files:

All of the files linked below were created using SolidWorks, however, many of the designs were originated/conceived using Rhino software.

We designed our part by first 3D modeling the part we wished to obtain by pouring silicone into a mold. From there, we split the part vertically, and used each half to create cavities in a solid block. Lastly we needed to perform a complex split of the remaining part(s) of the block to create our mold top and bottom. The CAD files for our first iteration can be found here.

We continued iterating on our part by adhering a solid piece of silicone to the bottom in order to increase the thickness of the bottom of the part to achieve a more ideal bend. We do not have CAD parts for this piece, as it was poured from a stock mold found in the fabrication lab. The piece was trimmed to fit the surface area of the original, bonded part; the piece thickness was ~6mm.

Due to 3D printing delays, we were unable to iterate on the cavity shape as frequently as we had liked. The makeup for lost time, we developed a part which would allow us to cast and test six of our most promising cavity designs with 1 3D print. The files for this design can be found here.

Lastly, we combined the observations and results of testing multiple designs with minimal 3D prints into our final design. Luckily, this worked nearly perfectly, was easy to both pour and pull, and exceeded our expectations for Rubbery Things. The files for the final iteration can be found here.

Code Files:

Our original code can be found here. This code contains both Python files intended to be run on a computer, as well as MicroPython files intended to be run on a Raspberry Pi Pico. Some test files work as intended, however, the final display shown at Rubbery Things is not able to be achieved with this code.

Our final code can be found here. This is the code that was used during the final show. The folder contains Arduino code intended for an Arduino Uno and Python code for a computer. In order to successfully run this code, some elements (including port names, pin numbers, etc.) will need to be updated by the user.

Citations:

“Creating a Hand Tracking Module Using Python, Opencv, and MediaPipe.” Section, https://www.section.io/engineering-education/creating-a-hand-tracking-module/.

M. N. Golchin, A. Hadi and B. Tarvirdizadeh. Development of A New Soft Robotic Module Using Compressed Air and Shape Memory Alloys. In 2021 9th RSI International Conference on Robotics and Mechatronics (ICRoM), Tehran, Iran, Islamic Republic of. 517-522. https://doi.org/10.1109/ICRoM54204.2021.9663519

Partner Contributions

Maddie:

1. Created final CAD files for finger parts (SolidWorks)
2. Designed and fabricated circuit
3. Wrote Raspberry Pi Pico, Arduino, and Python scripts
4. Maintained and authored documentation
5. Created conceptual sketches

Xiaofan:

1. Spearheaded initial design research
2. Designed and built finalized display box
3. Designed hinge components
4. Created final project video
5. Wrote weekly updates for the group

Both:

1. Conceived final project display concept
2. Pour and bonded silicone parts
3. Continuously researched and updated cavity design

Statement of Objectives

The objective of this project is to create a soft robotic sculpture that reflects the organic response of plants to external stimuli, specifically touch. The sculpture consists of silicone-based parts in the shape of flowers and venus fly traps, which are pneumatically actuated based on capacitive touch sensing. When the parts are touched, the motors activate and fill the silicone flytraps/flowers, creating the illusion of the plant bending inwards, as if closing into the touch. After a few seconds, the parts deflate and return to their original state.

The goals of this project are:

1.  To demonstrate the potential of soft robotics to create organic, lifelike movements that are inspired by nature.
2. To explore the concept of passive response in plants and how it can be applied to robotics.
3. To engage and educate the target audience about the capabilities of soft robotics and the ways in which they can be used in creative applications.

The target audience for this project includes individuals who are interested in robotics, art, and the intersection between the two. This includes artists, engineers, students, and members of the general public who are curious about the possibilities of soft robotics. By showcasing the sculpture in a public setting, the project aims to spark interest and conversation around the topic of soft robotics and its potential to transform our understanding of nature-inspired design.

Reflection

The use of soft robotics technology in the creation of the pneumatic sculpture provided a unique opportunity to explore expressive design and how technology can be used to create organic, lifelike movements. By utilizing silicone-based parts, the sculpture was able to mimic the soft, pliable nature of natural forms, such as flowers and Venus fly traps. The pneumatic actuation allowed for precise and subtle movements, which created an immersive and engaging experience.

The inclusion of the acetate element was primarily for the purpose of adding stiffness and introducing a new material that is somewhere in between hard and soft. The use of capacitive touch sensing to trigger the pneumatic actuation added an interactive element to the sculpture. By responding to touch, the sculpture created a sense of intimacy and connection with the viewer, as the movements of the sculpture were a direct result of the viewer’s actions. This aspect of the sculpture highlighted the potential of soft robotics to create expressive and interactive designs that engage and captivate audiences.

Furthermore, the use of soft technologies for expressive purposes in this project opens up a range of creative possibilities for future projects. Soft robotics technology has the potential to be used in a variety of expressive applications, from art installations to interactive toys, and can create lifelike and engaging movements that mimic natural forms. The technology also allows for a level of customization and flexibility that is difficult to achieve with traditional robotics, as the soft materials can be molded and shaped into a variety of forms.

Outcomes

Successes:

1. The project successfully utilized soft robotics technology to create a unique and engaging sculpture that mimics the organic movements of plants.
2. The use of silicone-based parts allowed for a lifelike and flexible appearance, which contributed to the immersive experience for the viewer.
3. The capacitive touch sensing technology provided an interactive element to the sculpture and allowed for a direct connection between the viewer and the movement of the sculpture.
4. We successfully implemented an FSM in circuit python to control the movement of the motors which resulted in varied inflating and deflating motions for the plants.
5. The iterative design process led to the creation of some cool and unique silicone parts.

Failures:

1. The range of motion for the Venus fly-trap as well as the flowers was limited.
2. The use of acetate as a rigid and inflexible material for the leaves of the venus-fly trap resulted in a less organic and lifelike appearance for this part of the sculpture.
3. The project did not fully explore the potential of machine learning algorithms to create more nuanced and lifelike movements.
4. The project did not fully explore the use of alternative actuation methods, such as shape memory alloys or electroactive polymers, to achieve a higher range of motion for the venus fly-trap leaves.

Photographs

Citations

https://robotreporters.com/the-robotic-venus-flytrap-and-other-bio-inspired-soft-robot-actuators-psas-from-purdue-university/

Technical Documentation

• Codebase: https://drive.google.com/file/d/1PW6Rl5aj-DYl_8-PLJQsC3fAFIf5Q_uT/view?usp=share_link 
• CAD Flytrap: https://drive.google.com/file/d/1Xm4FTwDL6hjF1uotGPG8O9Ds15u_xU2T/view?usp=share_link 
• CAD Flower: https://drive.google.com/file/d/1res6GHl9D_EOqtkSACYrhW3BDqG5zrRN/view?usp=share_link 

Contributors

Aditti Ramsisaria:

• Mold design for fly-trap actuator and flower
• Electronics and code for pneumatic actuation
• Acetate mesh wiring

Catherine Liu:

• Silicone fabrication of parts
• Acetate mesh design and laser cutting

Both:

• Concept and implementation ideation

Project Objectives

To create a tactile experience that captures the nuance of human touch through gesture and movement. The wearable bracelet presents a novel approach to appreciating the complexities of human interaction and enhances our ability to communicate and connect with one another on a deeper level.

Reflection on the creative design opportunities

In our world, human gestures and phrases carry nuanced connotations not captured by verbal or visual communication. Soft robotics provides a unique opportunity to explore the subtleties of non-verbal communication and how they can fill in the gaps. In this project, we explore the use of silicone to create gesture-activated bracelets that aim to mimic the tactile experience of human touch.

Throughout the design process, we embrace the skin-like qualities of silicone and the aesthetic material changes during pneumatic actuation to communicate non-verbal affection and comfort in response to a gesture of greeting. The design of the bubbles on the bracelet and how they felt and looked on the skin was key consideration. The process of perfecting these involved experimenting with different shapes, sizes, and textures. Choreographing the actuation of the bracelet involved experimenting with the speed and pressure of air to create pulses that represent what the sender wants the receiver to feel when they perform a gesture. This required a deep understanding of the subtleties of each gesture and how they can be translated into a physical experience.

The marbling and coloring of the silicone offer an artistic interpretation of the grotesque nature of human flesh. This serves as a representation of the raw emotion, intimacy, and vulnerability that can be associated with touch-based communication.

Outcomes

SUCCESSES

Overall, we are very happy that we achieved creating an actuating bracelet that had such an interesting feeling and look to it. There are always more opportunities and avenues we wish we had time to further explore, but we did experiment a lot throughout, so we feel satisfied with our iterations. The downfall to lots of experimenting is that we spent a lot of time failing instead of moving toward a final form. We mainly played with different ways of actuating (phasing, alternating, and a gradual wave-like actuation), size, thickness, length, color, and sensors. However, our vast iterations proves we were willing to try things that were challenging and still found many great additions for our final bracelet. For example:

• We figured out early on that we enjoyed the bubble form and how interesting it looks and feel. We were able to easily iterate to make the bubbles expand properly on both sides. This created a nice sensation on the skin while wearing the bracelet. This was a consistent success with our prototypes and the final form.
• We created a mold that successfully caused an alternating actuation, which was incredibly cool, but wasn’t included in the final iteration because of other challenges and lack of time.
• We liked almost every color we made and got to have a lot of fun experimenting with this in the end. We believe that our colors create a very interesting story in the final product that really helped us create our story into something compelling
• Tying the bracelet together was interesting because it was less iterated on, but we found the sewing to be the easiest and most secure way, which actually caused us to create some interesting bracelets. We sewed a bracelet together which ended up looking really cool and it was a great iteration in our collection. Overall, the sewing was quite secure and we didn’t have to worry about it ripping or falling off.
• The accelerometer sensor ended up being very cool and we were able to make 3 different gestures and choreographed 3 different actuations for each gesture by changing the input to the air pump. We were also able to actuate the two sides of the bracelet with different timing, which made the actuation look more complex and interesting, kinda like a wave. This was a great success to us because we think it makes the interaction with the bracelet more interesting by creating multiple ways to communicate through this bracelet rather than having one input and output.

CHALLENGES

1. Bonding the silicone. Our bracelet mold had thin tubes running through it for actuation purposes which caused a lot of issues during the bonding process. The tubes get getting plugged which resulted in the actuation/inflation of the bubbles being very uneven.
2. 3D Printing. The 3D printers offered were not long enough to accommodate the full length of the bracelet which meant that we had to figure out a way to connect two silicone parts seamlessly. This proved to be pretty difficult and resulted in a very fragile bracelet. The IDEATE printers also broke halfway through the course so we couldn’t experiment with different connecting part designs that may have resolved the issue above.
3. Suctioning air out in the motor + pump system. When we created the system to actuate the bracelets we found that they didn’t vacuum the air out which meant the bracelets were at risk of popping (since the top layer was very thin). To work around this, we poked holes in the tubes to allow the air to leak out when the bubbles deflated. This allowed us to control the inflation and deflation in a way that was very natural.
4. Gesture detection vs classification. Initially, our plan for gesture detection was to collect data with the accelerometer to train a classifier for predicting gestures. However, there wasn’t enough memory on our Arduino and filtering out data points was outside the scope of the project so we ended up going with a gesture detection system based on thresholds of x, y, and z values on the accelerometer.

Citations

Technical documentation

Source code:

Original CAD files:

Photographs:

https://drive.google.com/drive/folders/1otIVnCnxDc3Mx3z4TsxX-oGGNbQXWG-d?usp=sharing

Video:

Contributions

Gia

• wired up circuitry on the breadboard and accelerometer
• Sewed bracelets together
• made a box for final video
• edited final photos and video
• modeled bracelet for video and pictures

Fiona

• created the CAD for the mold used in the final product
• casted, bonded, and colored silicone bracelets for the final demo and video
• choreographed the actuation for the final bracelet gestures
• coded a state machine based program for gesture detection using an accelerometer
• took pictures and video for final documentation

Both

• ideation
• created CAD molds and casted and bonded silicon prototypes
• tested prototypes and documented this
• sent in 3D prints and acquired them
• wrote part of documentation
• tested heart rate monitor in class
• made velcro for accelerometer

Project Objectives:

To imitate a living organism that reacts to human touch/proximity by way of group movement. The organism reactions should feel organic and unpredictable, engaging the audience.

Reflection on the Creative Design Opportunities:

We embraced the use of silicon, pneumatic actuation, and capacitive touch sensing to create a feeling of movement and mysticism in the piece. The silicon paired particularly well with the capacitive touch sensing while embedding the necessary wires into the individual silicon tentacles. Then our inflation technique, while simple, was effective in creating the desired movement.

Unfortunately due to 3D printer problems, the shape of the individual tentacles was quite blocky as opposed to our ideal, more rounded shape. However, we were able to effectively counteract this inorganic feeling through our use of color and environment staging. The 1-to-2 pink to orange gradient in fluorescent colors mimicked real sea anemone in a very productive way. Additionally, the off-white clay placed around the base of the anemone brought a natural texture to the surroundings.

Outcomes:

We are quite pleased with how our piece turned out. Our audience was surprised and delighted by the interactions with anemone. The color was especially well received as people had not seen silicon cast as a gradient before. They were particularly excited by one of the tentacles that had a lot of movement. The box also worked well by creating a “blank” display space, while also, of course, hiding all of our extra wires. The natural environmental quality was also not lost due to the space at the top of the box being made into a rough terrain. Serendipitously, the motors’ noises played a fun part in the final exhibition, with some audience members asking if the sounds were intentionally included.

The motors, however, did initially pose a challenge to us. They could not vacuum air out as advertised, so we had to find a work-around to still drain air out of the tentacles. In the end, we poked holes in the tubing itself to create intentional air leaks. This worked very well, the deflation process appeared very natural.

Another large issue for us was the defunct 3D printers, limiting what our shapes could be to our first iteration mold. However, as mentioned above, that seemed to also work out. A notable comment by an audience member was that they liked the shape because it felt more “crystalline”, amplifying the surprise and mysticism when the anemone would start to inflate.

Citations

K. Suzumori, S. Iikura and H. Tanaka, “Development of flexible microactuator and its applications to robotic mechanisms,” Proceedings. 1991 IEEE International Conference on Robotics and Automation, Sacramento, CA, USA, 1991, pp. 1622-1627 vol.2, doi: 10.1109/ROBOT.1991.131850.

Qi Wang, Zhenhua Wu, Jianyu Huang, Zhuolin Du, Yamei Yue, Dezhi Chen, Dong Li, Bin Su. Integration of sensing and shape-deforming capabilities for a bioinspired soft robot. In Composites Part B: Engineering, Volume 223, 15 October 2021, doi: 10.1016/j.compositesb.2021.109116.

T. Wang, Y. Zhang, Z. Zhu and S. Zhu, “An Electrohydraulic Control Device With Decoupling Effect for Three-Chamber Soft Actuators,” in IEEE/ASME Transactions on Mechatronics, vol. 27, no. 3, pp. 1683-1691, June 2022, doi: 10.1109/TMECH.2021.3087196.

Technical Documentation

Code:

CAD Files

Photographs

Contributions

Elise:

Silicon Fabricator: Mixed the silicon and poured it into the mold to make our tentacles. Responsible for the silicon color gradient idea.

Circuit Board Engineer: Wired the Raspberry PI, MOSFETs, capacitor, pumps, etc.

Box Laser Cutter: Designed and laser cut the box. Filled the top with paper clay.

Leah:

Movement Choreographer: Designed the intended timing of each pump to produce movement in each tentacle, creating 6 different “dances” for the anemone to perform.

Programmer: Wrote the code that turns the pumps on and off and reads the capacitor input.

Pump Mechanic: Poked holes in each tentacle pipe to cause a controlled leak. Determined the number of holes after a series of tests. Connected and hooked up each tentacle to a specific pump.

Both:

Mold Designers: Worked together to design the mold. Figured out and decided on a two-chamber system early on in the project.

Assistants: Each assisted the other with their primary duties. Leah assisted Elise with fabricating tentacles and wiring the MOSFETs. Elise assisted Leah with debugging and hooking up pumps.

Currently, we are working on fitting everything into the flower pot we bought as housing, and final wiring and testing of parts. Based on Garth’s feedback, Aditti also adjusted the code so that when 1 part is triggered, all the other parts also slightly inflate and deflate (giving them a little more life)

In class, we are hoping we can test our electronics with all the parts connected, and try fitting them into the flower pot housing.

gesture detection

We first found the thresholds for the four directions (left, right, forward, back) through trial and error and created conditions in the main loop to check for changes in the x, y, and z values that crossed these thresholds. We took inspiration for the algorithm from this paper: https://www.irjmets.com/uploadedfiles/paper/volume3/issue_2_february_2021/6052/1628083249.pdf

Then, we took at the axes of movement for three gestures: normal wave (left to right), cat wave (up down), and a palm flip. Based on the direction of movement across a time window, we were able to create loops in the main sequence to detect these movements.

Overall, this week we made good progress. We were able to 3D print our mold and cast our part for the final bracelet. We were also able to create a program that detects 3 types of gestures.

Casted Bracelets

https://drive.google.com/file/d/19sY36DcLptIkVzm0aVcRVbvsjIRpSGyS/view?usp=sharing

(our video testing our prototypes)

We casted a bunch of prototypes and we are trying to put together our final bracelet. We tested them all today and we are running into some issues with the tubes keep popping off, but we think we got some finalized versions that should work once we tie it together in a bracelet!

Here is us testing the whole bracelet mechanism together with all the gestures!

Final test prototype to see if it will work to silicon two bracelet parts together:

New objectives for the upcoming week

• Putting everything together: bracelet construction and making box with tube connection and making sure everything is seamless for show and documentation

need to buy

• idk maybe string if we want nicer string?

Once this decision has been made, we’ll update our existing CAD to both reflect the new cavity shape (if applicable) as well as the thicker bottom of the part that we discussed in previous updates. These modifications should be fairly quick to implement and send to the 3D printer as the current CAD is modularly designed!

We’ve also begun working on code for the showcase display of our design. The concept behind our display is that a computer vision program would see the user’s hand, decide whether it was open or closed, and activate the pump accordingly such that our model would mirror the position of the user’s hand.

The computer vision portion of the code is completed:

We are currently working on connecting the pumps to be controlled by a raspberry pi pico. The last step will be connecting the two portions of code together!

This is the new hinge model, which we expect to be printed in ABS and can be attached to the finger by means of a strap.

We were able to 3d print all of our final molds, including the expanded and contracted meshes with fine detail. These will be cast by 4/19, and ready to go for the final assembly.

We also finished our system design. Instead of computer control, we decided that direct interaction through a series of handles or rings would provide a more engaging experience for the users. The softness and springiness is intrinsic to our designs, so allowing people to get hands on with it makes more sense. The ability to also distort the meshes at different angles and forces is an advantage of the direct handling. The meshes will then be placed in clear acrylic frames, which will then be connected to the table.

For our final presentation, our conversation with Professor Zeglin was extremely helpful in redesigning the system. We tend to thing very utilitarian with our projects, so having a discussion about presentation and style was very helpful. Our idea is to raise the frames and experiment with lighting over the weekend.

Frame fabrication will take place later this week. We want to leave enough time to test the size, shapes, and interactivity of our system to ensure we make the most use of the interesting properties of the auxetic materials.

Monday, 4.10:

• Message Daniel about the pump thing
• Tried more scenarios with the pumps, no success
• Lent out vacuum pump, did not work
• Tried a pinhole technique for draining air
  • We have decided that this is the route that we will go for the rest of the project
• Started casting another tentacle, this time in orange

Wednesday, 4.12

• Sealed orange tentacle
• Made capacitive motor piano
• Reorganised breadboard to be more clean
• Updated the code
• Experimented more with holes in the tubing
  • Four holes seems good, inflating the other side at the same time seems to deflate it at a nice rate
• Made a little dance

Monday, 4.17:

• Cast duotone tentacle
  • Later: came back to bond the tentacle, as well as cast another duotone tentacle
• Worked on dances

Tuesday, 4.18:

• Continued work on casting and bonding