Documentation

1. Choosing the final project idea:

• I picked the soft gripper due to its balanced difficulty, perfect for a novice like me. The original concept could be easily expanded upon due to the addition of a codable air pump, which may be an enjoyable challenge for me. Furthermore, it includes programming, but in a new language (Arduino). With a combination of robotics, engineering, and computer science, this idea greatly interested me as a fitting senior year project.

1. Programming the Air Valve

As a first-year engineering student, I wanted to explore a project that could easily incorporate entry-level skills but also challenge myself in this STEM field. With that in mind, I began researching for such projects, such as mechanical wings and origami robots. However, when Mr. Dubick referred to a pneumatic robot, providing an example of a tentacle, I knew that I wanted to follow suit in the soft robotics area. Thus, I decided to create a soft robotic gripper.

Design Statement: If successful, my soft robotic gripper will be able to be controlled to inflate and deflate in order to pick up and drop items. This project was based on Harrison_89’s soft robotic grabber on Instructables.

In the beginning of school, I first researched and ordered materials needed for my gripper. While the engineering lab had most of the materials required for the molding and casting portion, I needed to buy the pumps, valve, and other circuitry items for the programming. I also looked into how to use my boards, Cricket and Circuit Playground Express, which required different programming formats. Once I received my materials, I began to experiment with the circuit boards, actually getting familiar with the programming. The Circuit utilizes Arduino, MakeCode, or CircuitPython, none of which were familiar to me. At first, I started off with Arduino, where I was able to program the LED to blink and show to Mr. Dubick. I then worked with the MakeCode, which provided an easier way to directly code the different systems of drives, motors, and signals. With MakeCode I was able to program an air pump to inflate or deflate a balloon, showing steady progress towards my coding.

In January, I began the molding and casting process, following the Instructables to create the cardboard molds with the laser cutter. Mr. Dubick aided me in utilizing the degassing chamber to eradicate air bubbles in the EcoFlex silicone mixture, which lessened the chances of my gripper popping. Each gripper requires a top and bottom piece, and I made a thin and thicker version of each. For both styles, I combined the pieces with more EcoFlex and poked a hole to the center for the tubing to blow the gripper up. After they were fused, I ribboned each leg and poured more EcoFlex to ensure the ribbons maintained position, the gripper could still hold on to other items, and the gaps between the tubing and the gripper would not leak air. Through trial and error, I ultimately used the thicker gripper as the final gripper, as they were less likely to have air balloon up in one area.

Once my physical gripper was done, I could focus more on coding. I jumped around from MakerCode to Arduino, trying to get the air valve to work, but to no avail. Finally, I moved on to CircuitPython, which finally allowed me to inflate and deflate the gripper within the same program. With that set, I could now use the Circuit’s buttons to control when to inflate and deflate.

While this whole project took longer than I expected, I was most surprised at the amount of time it took to completely mold and cast the gripper. Besides the top and bottom pieces, I also had to account for the ribbons and filling in gaps to ensure the gripper was completely sealed. Furthermore, the programming also became an unexpected challenge. New to the methods of coding the Crickit and Circuit, I couldn’t figure out how to control the air valve for a long time. However, as I want to major in computer science, this provided an exciting opportunity to test my computer skills. With Dr. Harris’ guidance, I figured out that the MakeCode format was too simplistic and that I needed to use CircuitPython, which allowed for a wider range of actions. Python programming allowed me to control the timing of the pumping and the direction of airflow with the air pump.

For the next step in this project, I would like to create a container to store the air pumps, air valve, tubing, and circuit boards. This would most likely be a hexagonal box to snugly fit the shape of the Crickit. The Playground Express would be exposed up, in order for the control buttons to be used to inflate and deflate the gripper. Utlizing some sort of crane-like device would also be useful in maneuvering the gripper, as currently I have to handhold it over the intended object.

This soft robotic gripper has shown me how I can persevere even when it seems improbable. When I became frustrated with not being able to fix my programming and make the air valve actually work, I didn’t quit my work and stay content with only one working motor. Instead, I persisted to continue researching about this new format and programming the Circuit. Eventually, this clearly paid off, as my project demonstrates both a satisfactory physical and electrical completion.