Sensing everything

Presented at CHI 2012, Touché is a capacitive system for pervasive, continuous sensing. Among other amazing capabilities, it can accurately sense gestures a user makes on his own body. “It is conceivable that one day mobile devices could have no screens or buttons, and rely exclusively on the body as the input surface.” Touché.

Printed strain sensors = "sense of touch"

In future, the robot could find its own way. A sensor will endow it with a sense of touch and help it to detect its undersea environment autonomously.

“One component in this tactile capability is a strain gauge,” says Marcus Maiwald…“If the robot encounters an obstacle,” he explains, “the strain gauge is distorted and the electrical resistance changes. The special feature of our strain gauge is that it is not glued but printed on – which means we can apply the sensor to curved surfaces of the robot.”

The sensor system on this robot is not all that complex; strain gauges are literally a dime a dozen (or less). But the configuration of the sensors reminds us of an animal body, and that’s what intrigues us. Since the strain sensors are printed along the surface of the robot in a continuous way (rather than being attached at some specific point), we’re reminded of how touch receptors are embedded throughout the skin, bringing to mind the phrase “sense of touch.” The Roomba has a mechanical sensor that is technically similar to the ones in this new robot, but we don’t talk about the Roomba having a sense of touch because the sensor is in a discrete place. To have a sense of touch you need to be able to sense contact (almost) anywhere on the surface of the body.

Laser Doppler Vibrometry in triage

Vibration sensors help EMTs take vital signs from a distance of five to 40 feet:

Because time is the most precious resource in a crisis, every second shaved can be a life-saver. With this in mind, S&T wants to make a revolutionary leap forward in triage. Why not 30 seconds per person? And why not from a distance?

Laser Doppler Vibrometry [has] been used in aircraft and automotive components, acoustic speakers, radar technology, and landmine detection. When connected to a camera, the vibrometer can measure the velocity and displacement of vibrating objects. An algorithm then converts those data points into measurements emergency medical responders can use in their rapid assessment of a patient’s critical medical conditions.

Whiskers as haptic sensor arrays

Whiskers provide animals with complex perceptual content. In fact, all the things that whiskers actually do are fascinating.

The dimensionality of the data can be modeled according to how an animal moves them through space:

Rat whiskers move actively in one dimension, rotating at their base in a plane roughly parallel to the ground. When the whiskers hit an object, they can be deflected backwards, upwards or downwards by contact with the object. The mechanical bending of the whisker activates many thousands of sensory receptors located in the follicle at the whisker base. The receptors, in turn, send neural signals to the brain, where a three-dimensional image is presumably generated.

Hartmann and Solomon showed that their robotic whiskers could extract information about object shape by “whisking” (sweeping) the whiskers across a small sculpted head, which was chosen specifically for its complex shape. As the whiskers move across the object, strain gauges sense the bending of the whiskers and thus determine the location of different points on the head. A computer program then “connects the dots” to create a three-dimensional representation of the object.

More on that “three-dimensional image” from the end of the first paragraph — whiskers indeed construct a high resolution spatial map:

Based on discoveries in primates and cats, scientists previously thought that highly refined maps representing the complexities of the external world were the exclusive domain of the visual cortex in mammals. This new map is a miniature schematic, representing the direction a whisker is moved when it brushes against an object.

“This study is a great counter example to the prevailing view that only the visual cortex has beautiful, overlapping, multiplexed maps,” said Christopher Moore, a principal investigator at the McGovern Institute and an assistant professor in the Department of Brain and Cognitive Sciences, where he holds the Mitsui Career Development Chair.

Researchers are now working towards developing code for a whisker-like sensor array to be used for robotics. Could this software have human interface applications as well?

This reminds me of the impressive and thought-provoking Haptic Radar/Extended Skin Project. Although the sensing medium in that case was ultrasound rather than a deformable, physical substrate, and the resolution of the stimulators much lower, the researchers state that they intend to make the system more whisker-like as they develop it.

[via Science Daily]

Compact tactile sensors

Man, would I ever love to get ahold of one of these tactile sensors developed for the Shadow Robot Company. Responding to pressure ranging between 0.1 N and 25 N using a quantum tunneling composite material, each sensor has up to 34 individual sensing units, on-board digital signal conditioning, and is the size of a human fingertip. I would bet that this sensor could be used to crudely model the non-pacinian 3 (np3) psychophysical sensory channel, which constructs an acute neural image of skin deformation.

A development kit is available for £1450, which includes one sensor and some interfacing materials. That’s a bit out of my range, but if someone from Shadow is reading this, I will give you free publicity if you send me a sample!

(via aiGuru)

Two essential posts from a man like Tom Igoe

Lots of great stuff at the blog of Tom Igoe, a physical interaction designer and new media artist. He points to a nice little .zip file of circuit schematic symbols in Illustrator format. But even more essential is his tutorial on how to generate graphs of sensor data with three lines of Wiring code. I could definitely see using this instead of MATLAB to create quick example images for presentations and the like. Plus, all the software you need is free and comes standard with OS X.