Infrared-based haptic ‘buzz’ device found to work as well as vision in experiment

August 12, 2014

Favela observes Amon as she uses the Enactive Torch during a demonstration of detecting a doorway (credit: University of Cincinnati)

University of Cincinnati psychology grad student Luis Favela has tested the ability of blind people* to navigate a house-like structure using a device called the Enactive  Torch.

Favela found the device enables the visually impaired to judge their ability to comfortably pass through narrow passages, like an open door or busy sidewalk, as well as if they were actually seeing such pathways themselves.

The device uses a near-infrared (IR) transmitter (similar to those used in most TV remote controls) and an IR sensor to “see” objects in front of it, with a range of 10 centimeters (~4 inches) to 1 meter (~39 inches).

When it detects an object, the device generates a vibration through an attached wristband (feels similar to a cellphone “vibrate” mode). The buzz increases in intensity as the torch nears the object, letting the user make judgments about where to move.

The experiment

In Favela’s experiment, 27 undergraduate students with normal or corrected-to-normal vision and no prior experience with mobility assistance devices were asked to make perceptual judgments about their ability to pass through an opening a few feet in front of them without needing to shift their normal posture.

The Enactive Torch uses infrared sensors to “see” objects in front of it (credit: University of Cincinnati)

Favela tested participants’ judgments in three ways: using only their vision, using a cane while blindfolded and using the Enactive Torch while blindfolded. The idea was to compare judgments made with vision against those made by touch.

The results of the experiment were surprising. Favela figured vision-based judgments would be the most accurate because vision tends to be most people’s dominant perceptual modality. However, he found the three types of judgments were equally accurate.

“When you compare the participants’ judgments with vision, cane and Enactive Torch, there was not a significant difference, meaning that they made the same judgments,” Favela says. “The three modalities are functionally equivalent. People can carry out actions just about to the same degree whether they’re using their vision or their sense of touch. I was really surprised.”

Favela plans additional experiments requiring more complicated judgments, such as the ability to step over an obstacle or to climb stairs. With further study and improvements to the Enactive Torch, Favela says similar tools that augment touch-based perception could have a significant impact on the lives of the visually impaired.

How to buy or build your own Enactive Torch

The Enactive Torch is currently manufactured on a not-for-profit basis by Creative Robotics Ltd. Enactive Torch developers are creating an international not-for-profit Enactive Interface Consortium that will organize the development, construction, and distribution of the Enactive Torch as an open-source research platform under the Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Unported (CC BY-NC-SA 3.0) license.

“For those with electronics skills we have made the technical details, including the full circuit diagram and an example of Arduino source code freely available: Enactive Torch v3.0 tech. sheet,” according to co-developer Tom Froese, DPhil, a postdoctoral fellow of the Ikegami Laboratory at the University of Tokyo.

“If the future version of the Enactive Torch is smaller and more compact, kids who use it wouldn’t stand out from the crowd;’ they might feel like they blend in more,” he says, noting that people can quickly adapt to using the torch.

Favela presented his research, “Augmenting the Sensory Judgment Abilities of the Visually Impaired,” at the American Psychological Association’s (APA) annual convention, held Aug. 7–10 in Washington, D.C.

* The Centers for Disease Control and Prevention (CDC) predicts that more than 6 million Americans age 40 and older will be affected by blindness or low vision by 2030 — double the number from 2004 — due to diabetes or other chronic diseases and the rapidly aging population. The CDC also notes that vision loss is among the top 10 causes of disability in the U.S., and vision impairment is one of the most prevalent disabilities in children.