The project is conceived on the idea of using your arm or elbow to open a common round doorknob. The intention is for it to be used during the Covid-19 crisis. Therefore, the design is open source and free to be modified for specific dimensions. All parts of the assembly can be 3d printed, including the mechanical parts. The attachment allows a door to be pushed and pulled without spreading or having hand contact with viruses and pathogens. The goal was to achieve a simple design can be easily 3d printed and distributed through the maker community around the globe. One distinct feature of this model is that it is compatible with cylindrical doorknobs which are common in different parts of the globe. Thermochromic pigments were implemented on the door-attachment so that surface leaves a temporary trace of discoloration on itself if someone touched it with their hands.

Design Team

Rafael Vargas- Creative Director and Additive Manufacturing Expert

Cristina Centeno- Computational Designer

Chad M Wall- Mechanical Designer

Attachmentassembled in a typical round knob and a person about to open the door using the arm

Opening motion of the door knob attachment for a push opening door.

Summary of usability of dorrhandle attachment

Installed clamp with pull lever option assembled (for pull doors)

main 3d printed parts and assembly options.

Prototypes ans Iterations of design process

Throughout the Covid-19 pandemic many designers have responded with designs and prototypes that intend to provide solutions to various problems caused by the distinct peculiarities possessed the virus causing the situation. One of the problems that is very prevalent is the inevitable exposure to pathogens when persons have direct contact with common surfaces like light switches and doorknobs. Round doorknobs specifically are difficult to open without direct contact with the body.

The design begins from the intention of 3d printing a model that could be attached to any round doorknob, this way enabling the possibility of pushing or pulling the door after turning the knob while using parts of your arm other than the hands. All the parts of assembly can be 3d printed freely and the parts can be modified, edited and remixed to fit the specific conditions of the users.

In addition to providing the design to be open source and available to everybody, material experiments have been done by using color changing pigments on the 3d printed parts with the intention of leaving an imprint of people who have incorrectly touched the doorknob. That way we encourage cleaning and disinfecting the attachment when it has been left with finger marks. It also serves as a reminder for not touching the door with your hands. The heat reacting pigment responds to body heat and leaves a temporary mark that can last for up to 10 minutes depending on the room temperature.

The design is downloadable here.

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