Haptic Device Offers GPS Navigation for the Blind
Meghan Brown posted on September 11, 2015 |
Navigation system taps into user’s sense of touch to provide directions for the visually impaired.
A new handheld navigation device using haptics (the sense of touch) shows potential to assist the visually impaired find their way around.

Engineer Adam Spiers, a post-doc associate at the Yale University robotics lab, created the handheld, shapeshifting cube which he calls the “Haptic Sandwich.”

The top half of the cube twists to indicate a change of direction, and extends forward to indicate the distance required to reach the destination. Users know they have reached their destination once the shape has returned to its original home position.

The Haptic Sandwich changes shape to direct users. Image courtesy Yale University.
The Haptic Sandwich changes shape to direct users. Image courtesy Yale University.

Spiers primarily built the device using a research grade Stratys Fortus 3D printer capable of printing dissolvable support material. This allowed him to design and build more intricate features for the internal mechanisms.

Printing elements of the gear transmissions directly onto the device parts reduced both the number of parts and the overall size of the device. This also allowed the necessary increased force and torque output from the servo actuators to enable device operation even in a tight grip.

The Haptic Sandwich is carefully designed to prevent places the user could get their fingers pinched during device movement.

Spiers said building the device took some trial and error because there was little precedent for it.

One of the great things about designing and building the device with a 3D printer, according to Spiers, was that whenever he made mechanical improvements to the device, he could easily email a part file to his collaborators at Open University in the UK. 

“They could then print out the new part and swap it out in their haptic device. This was also great for making copies of the device and having spare parts on hand,” he said. 

In terms of maintenance or repair, the Haptic Sandwich is designed to be dismantled and rebuilt simply and quickly, without requiring any special engineering skills.  This feature makes the device particularly appealing for potential consumer use.

The tool has already seen use within an interactive theatre production based on Edwin A. Abbott’s novel Flatland, in which it was called by the name “Animotus.”

Audience members with and without visual impairments were kept in complete darkness as they wandered through the performance space. As the audience moved about, a spoken narrative and sound effects told the story.

The Haptic Sandwich in use during the Flatland performance. Image courtesy of Yale University.

The Haptic Sandwich in use during the Flatland performance. Image courtesy of Yale University.

For the purposes of the theatre production, Spiers created an indoor GPS-like positioning system, which tracked people’s movements using a radio frequency-based localization system and tilt-compensated magnetometers (digital compasses) in a wearable suit.

A similar set up could be very useful within the home of a recently blinded individual.

Each haptic device communicated wirelessly with a laptop that managed the navigation system through custom software. 

Overall, the system achieved similar accuracy to what is expected from satellite GPS.

“I’d like to try this for the outdoors,” Spiers said. “Hook it up to Google Maps and see what happens.”  Having the device connected to GPS mapping services could allow navigation to any destination the user has the location or coordinates for, in both urban and natural environments.

Spiers also thinks Haptic Sandwich devices have the potential to guide sighted and visually impaired hikers effectively and accurately, while remaining unobtrusive and easy to operate. He believes too many haptic devices rely on vibration, which can be annoying or use audio cues that can be distracting for people with visual impairments.

More information on the Haptic Sandwich is available through the Yale University Grab Lab.

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