The Haptic Timer
A long time ago, I sold haptic devices to research labs at universities. They were complicated, precise instruments that were used to mimic forces in six or even seven degrees of freedom. The main applications were for researching teleoperation and virtual surgeries, though I encountered a few interesting applications beyond these areas.
The main challenge in haptics, especially kinematic haptics — the mimicking of forces of an object encountering another object — is latency. Force travels very fast through a rigid object. In the case of teleoperation, the target system needs to sense the force it’s encountering and then transmit it to the haptic device and then the haptic device needs to generate that force extremely quickly for the user to sense it.
How quick? The golden latency was under 1 ms.
Why? Because then the input needs to be transmitted back to the target system to apply the equivalent force and then close the loop and send the new force to the user.
In between the systems were applications, application layers, operating system layers, hardware drivers, and input / output devices, encoders, motor drivers, and the motors themselves. Any component could introduce lag and break the suspense of disbelief.
I have never performed laparoscopic surgery. I have stayed at a Holiday Inn Express and I have performed virtual surgery with a surgery simulator. At least at the time, the virtual surgery tool, which consisted of two haptic manipulators and a stereo scope for viewing the surgery, seemed rubbery. Pulling muscle tissue and poking a needle through cartiledge seemed real, but tapping on a bone or something hard had too much give.
When visiting research labs, there were other haptics applications that were innovative and had their pros and cons. One prosthetics lab using small inflatable blisters can transmitted pressure almost instantaneously from one surface to another with no controller, electronics, or other devices. An amputee missing the bottom portion of her leg could sense the pressure on the sole of her foot through the air blisters inflating on her knee.
Tactile haptic devices were also used in vests for combat simulators in some labs or as gloves to sense whether something was being held. Scientists were piercing the edge of human cognition and sensory experiences in their research.
Recently, I again encountered haptics albeit in a clever and simple way — as a timer.
When I was growing up, I had a timer that would help me brush my teeth. It was little alligator and I don’t recall if it was battery powered or not, but you’d press its toothbrush and it would brush its teeth for 30 seconds. You were to brush your teeth as long as it was brushing its teeth. In the 80s, 30 seconds of brushing was long enough to prevent cavities.
My electric toothbrush and it provides a timer function. How? It pulses the motor every 30 seconds to let you know how much time has passed. 30 seconds for bottom front, bottom back, top front, then top back. It’s almost inverse haptics, as the motor stops vibrating to indicate the passing of time, rather then turning on.
These new applications of simple and old technologies are a delight. We can contemplate new applications of mature technologies from a decade ago being revamped into new products.
Lidar in the fridge?
E-ink mirrors?
Cut and fit luminescent wallpaper?
Aerogel oven mitts?
Let the convergences continue.
