This Haptic Interface Will Blow You Away

In the field of human-computer interaction, haptic feedback systems lag far behind other key components, like display and input technologies. This disparity hinders the potential for creating more immersive and intuitive interfaces, as the sense of touch plays a crucial role in how we perceive and interact with the digital world. Current haptic technologies often struggle with limitations in precision, responsiveness, and versatility, making it challenging to replicate the nuanced tactile experiences found in the real world. Even in cases where the interfaces are up to the task, they tend to be cumbersome, limiting their widespread adoption in real-world applications.

Noncontact haptic technologies are presently being developed to reduce the burden and discomfort associated with attaching instruments directly to the body. A lot of buzz has recently surrounded an emerging technology called synthetic jets (synjets), which are simple devices that generate a zero-net-mass-flux jet of air. These devices are compact and inexpensive, and can be used to build contactless mid-air haptic interfaces that operate from a distance. They are capable of rendering complex haptic effects that can be controlled with a high degree of precision.

A trio of researchers at Carnegie Mellon University have taken a special interest in synjets, and have recently carried out some work demonstrating some of the types of haptic feedback that can be produced with them. They have also created a variety of prototype devices that demonstrate the versatility of the technology in a wide range of real-world applications. Finally, the team quantified the performance of their designs to assist other developers in building their own synjet-based systems in the future.

By way of background, synjets work by generating tactile feedback through rapid, controlled bursts of air. These jets are created by oscillating diaphragms or membranes within a small cavity, which alternately suck in and expel air through an orifice. Unlike traditional jets that require a continuous source of air, synjets operate on the principle of zero-net-mass-flux, meaning they produce pulses of air without a net mass flow. This capability allows synjets to deliver precise and localized bursts of air that can simulate touch sensations on the skin. In haptic interfaces, these air pulses can mimic the feeling of texture, pressure, or motion, enhancing the user's tactile experience without physical contact.

In this work, the team built synjets by using audio speakers as the driving mechanism, in conjunction with laser-cut acrylic pieces to help direct airflow. The synjets cost between 2 and 89 dollars to produce.

These devices were built into a virtual reality headset in one demonstration. The synjets would render sensations on the face to simulate sprays of water or car crashes in a driving simulator. A similar setup was used in an augmented reality application that showed how bursts of air can be used for giving navigational directions or alerting a user to waiting notifications.

By fitting a powerful synjet into a vehicle’s dashboard, it was demonstrated that functions like blindspot detection could provide feedback to drivers with steerable jets of air. Entertainment applications were also developed which augment television viewing and gaming.

The researchers have open-sourced their design files, and have also made instructions available for building custom synjet actuators in their GitHub repository. There is still plenty of room for innovation in this nascent field, so if you have some ideas, now is the time to try them out.