Soft Bubble Grippers
for Robust and Perceptive

The Tactile team at TRI is working on highly compliant tactile sensors and the algorithms to put them to good use.

Our “bubbles” and various other compliant sensors turn hard robots into soft robots, allowing for intentional and advantageous contact-rich, sometimes sloppy but always controllable, interactions between our robot’s body and the world.

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The Team

Our Tactile team brings together complementary research and engineering expertise in soft robotics, manipulation, humanoid systems, physical human-robot interaction, education, entertainment, software development and consumer electronics.

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Build a Punyo Gripper

Build Exploded View

Let's Get Started

We are excited to release the build instructions and design files for our Punyo Bubble Gripper v2.0 so that our friends and colleagues can test our technology, improve upon it, and take us closer to building robotic assistants for the home! This new version is built around Intel's Realsense D405 Depth Camera

The Punyo project information is distributed using the Creative Commons Attribution-NonCommercial 4.0 International license.

For access to all the information you need to build your own Punyo Gripper, please view & acknowledge the license.

Build Instructions v2.0

The following document provides instructions on how to build TRI’s tactile sensing Punyo Bubble Grippers. After reading this document, users should understand the following:

  • Safety hazards and mitigations
  • Bubble module fabrication
    • Tools, materials, supplies and fabrication file downloads
    • Acrylic “window” laser cutting, etching and threaded insert installation
    • Latex preparation and pattern printing process
    • Production of 3D printed components
    • Assembly techniques
    • Inflation and deflation
    • Bubble storage
  • Bubble Gripper assembly
    • CAD and 3D printable file downloads
    • 3D printing your bubble gripper parts
    • Threaded insert installation
    • Internal depth camera installation
    • Bubble module installation
    • Pressure sensing electronics and installation
    • Final assembly
  • Common mistakes
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Bill of Materials

You’re going to need some stuff to get started. Take a look at your shopping list.

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Part Files

Here’s the parts you’re going to want to get fabricating. Use your favorite colors and be sure to share your creation!

The following files will enable you to 3D print and laser cut all pieces you need for the complete Punyo Gripper assembly. STL files are 3D mesh files used for 3D printing. Vector files are used for laser cutting. SOLIDWORKS files are source CAD files that can be used to modify components.

Download Build Files

You can find v1.1 (based on PMD's picoflexx v1) instructions and build files here.


The Soft-Bubble Sensor works with ROS2 on Linux.

ROS Package

Work with Us

We developed a demonstration kit to showcase the Punyo Soft-Bubble Sensor. If you'd like to receive updates, please let us know.

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CWBB 2022

Build a Punyo Gripper: Education and Open Source for Humanoid Robots


Punyo-1: Soft tactile-sensing upper-body robot for large object manipulation and physical human interaction

Video Paper

SEED: Series Elastic End Effectors in 6D for Visuotactile Tool Use

Video Paper

Monocular Depth Estimation for Soft Visuotactile Sensors

Video Paper

Variable compliance and geometry regulation of Soft-Bubble grippers with active pressure control

Video Paper
TRI Press Release

Sensing is believing: More Capable Robot Hands with the Soft Bubble Gripper

Video Release

Soft-bubble grippers for robust and perceptive manipulation

Video Paper

Fast model-based contact patch and pose estimation for deformable dense-geometry tactile sensors

Video Paper

Soft-bubble: A highly compliant dense geometry tactile sensor for robot manipulation

Video Paper

Meet Punyo

Punyo is an artistic rendering of the Tactile team’s dream domestic robot. The word “punyo” is a Japanese word that elicits feelings of chubby, cute resilience - our Punyo concept robot is soft, interactive, affordable, safe, durable and capable. Most importantly, unlike many other robots, Punyo is not afraid to safely make a lot of contact and uses its whole body to get jobs done and interact with the world and its humans.

Punyo bots