hapticity » actuators

My hometown's newspaper puts those annoying quotes around the word "feel"

David Birnbaum — Wed, 12 Nov 2008 19:51:17 +0000

The San Diego Union-Tribune recently published an article about haptics:

On one computer, users could “feel” the contours of a virtual rabbit.

Do users “feel” the contours of a virtual rabbit, or do they just feel them? Do we “read” text on the internet, or just read it? When we watch a movie do we “see” the actors? Harumph.

The article is about Butterfly Haptics, which is a haptic interface based on magnetic levitation. I “felt” it at SIGGRAPH ’08, and it was extraordinarily crisp and strong. The only problem is that the workspace (range of motion) is tiny compared to other haptic interfaces, and there doesn’t seem to be a clear development path for expanding the workspace using magnetic technology. Nevertheless, it’s great to be able to add magnetic field actuation to the relatively limited number of technologies that can be used for haptic display.

Vibration motors

David Birnbaum — Mon, 07 Jul 2008 00:05:45 +0000

An Instructable on how to build a DIY vibration motor.

I bought a few vibration motors from Solarbotics a while back and they worked very well.

Brain-computer-tactor chair

David Birnbaum — Fri, 20 Jun 2008 16:08:12 +0000

Shown last month at MoMA, the Mind Chair:

A movie camera is attached to an enhanced grid of 400 solenoids installed in the back of the Mind Chair. People are able to sit in the chair, close their eyes and concentrate on the images which are vibrated into their backs by the solenoids.

Also check out the variant called Mind Chair Polyprop, which seems like an effort to make a more practical, mass-producible version.

(via Dezeen)

Flexible, scalable tactile displays

David Birnbaum — Thu, 12 Jun 2008 16:12:35 +0000

An announcement of mechanotactile displays you can wear like a Band-Aid. The potential for clothing and contoured surfaces is massive. Reading the article the first time through I thought the display used electrical skin stimulation, but looking again I noticed this:

The display can convey information to the wearer when the electrodes induce a voltage across the films. A voltage causes the films to compress down and expand outward. In doing so, the films put pressure on the wearer’s skin, inducing a “mild sensation.”

I wonder how “mild” they’re talking about. The sensations that a tactile display can deliver has a lot to do with the depth of the sensory organs it can reach. From the press release I’m guessing the stimulator doesn’t displace all that much skin, meaning it can do tactile notifications and maybe even Braille, but not vibration or edge display. For the details we’ll have to wait for the next IEEE Transactions on Robotics.

(via Engadget)

Mobile haptics in The Economist

Dave — Tue, 20 Mar 2007 23:36:34 +0000

The print edition of The Economist came out with an interesting article on mobile haptics last week, which is now available online. It points out that the iPhone lacks what little haptic feedback a normal phone provides in favor of a touch screen, and notes that Samsung’s SCH-W559, not yet available in North America, will utilize an active haptic display. That product uses Immersion’s VibeTonz technology, which I haven’t felt. Although the vibration signal is said to be “very precise,” I find vibration motors to be heavy and bulky and always having a weaker transient response and resolution than other actuation methods. But the first generation of mobile haptics is already getting by with unbalanced motors, so it seems to make some sense to try to refine them until other actuators hit the market.

The article also interviews Vincent Hayward of McGill University’s Center for Intelligent Machines who has been developing skin stretching techniques to simulate tactile stimuli normal to the contact area. I saw him present his “THMB” system at the Enactive conference in Montreal, and it looked damn cool. (“Looked” not “felt,” because again… no demo. Maybe I’ll make an appointment to walk over there one of these days and check it out.) It’s a MEMS, positioned on the device to be felt by the tip of the thumb (essentially the same place as Sony’s scroll wheel).

Speaking of which, I recently read about Sony’s own moble vibrotactile platform, which it calls the TouchEngine—an extremely thin vibration actuator made out of piezoelectric film. But it’s not for the thumbtip; it’s installed on the back of the device, and sits in contact with the user’s palm.