ForcePhone App Uses Ultrasonic Tone To Create Pressure-Sensitive Batphone

An anonymous reader quotes a report from The Stack: Researchers at the University of Michigan have created an app that makes any smartphone pressure-sensitive without additional hardware. The app, called ForcePhone, uses ultrasonic tones in the existing microphone and speaker hardware that respond to pressure for additional functionality for touchscreens. The app emits a high-frequency ultrasound tone from the device's existing microphone, which is inaudible to humans but can be picked up by the phone. That tone is calibrated to change depending on the pressure that the user gives on the screen or on the body of the phone. This gives users an additional way to interact with their device through the app alone. The additional functionality provided by ForcePhone can be used in a number of ways. Squeezing the body of the phone could take a user back a page, for example; or increased pressure on the touchscreen could act as a 'right-click' function, showing additional information on the app in use. Kan Shin, Professor at the University of Michigan, said, "You don't need a special screen or built-in sensors to do this. Now this functionality can be realized on any phone." He added, "We've augmented the user interface without requiring any special built-in sensors. ForcePhone increases the vocabulary between the phone and the user."

Batphone?

[rossdee]

DC comics lawsuit in 3 ,2, 1

Flawed

[Anonymous Coward]

Working at 18 khz, this is still within human capacity. It will irritate the hell out of dogs and cats.
And how is it supposed to work when you listen to music and play a game?
And not to mention battery drain.

Sorry. Complete rubbish.

Re: Flawed

[Christopher C]

The mosquito* is a device designed to repel most people under 25 years of age using a 17.4 KHz tone. It seems reasonable to me therefore that 18 KHz would be audible to people too, but it probably doesn't matter here; the tone is probably pretty low amplitude. This means it'll be both quiet and at the very threshold of what most people can even perceive. Useless? Don't be such grump! Its a pretty cool idea, even though they haven't worked out all the features yet. *The Mosquito: www.movingsoundtech.com

Re:

[rpstrong]

The GP linked article [phys.org] cites the tone as being over 18 KHz - but not by how much. I couldn't find a definitive number elsewhere; did I miss something?

Re:

[mrbester]

This does also rely on the speaker having the ability to output sound at that frequency.

Re:

[rpstrong]

According to this guy [stackexchange.com] - who actually did some testing - both the mic and speaker are typically good to at least 21 KHz. [geek.net.au]

Re:

[tomhath]

And how is it supposed to work when you listen to music and play a game?

The receiver can filter to that specific frequency, same as a ship can use sonar while the engine is running and the propeller is turning.

As far as irritating people, dogs, and cats - just keep the music turned up for a while; high frequencies are the first to go in the subsequent hearing loss and tinnitus.

Science 101

[Anonymous Coward]

The app emits a high-frequency ultrasound tone from the device's existing microphone

A microphone is for recording sound, not generating it.

Re:

[Hognoxious]

I thought that too, but you can use headphones as a microphone so I suppose the reverse applies.

Of course "can" and "should" are not synonyms, as anyone who's observed a dog using its tongue knows.

Re:

[Anonymous Coward]

Phones usually use condenser microphones, which have a built-in pre-amplifier and are therefore designed only to be used as microphones.

Re:

[Hognoxious]

Is "designed to" some kind of binding covenant enforced by heavenly thunderbolts?

Re: Science 101

[Blythe Bowman]

Speakers can be used as mics because they have an electromagnet inside simaler to what you find in an electric motor. Just as a motor can generate electricity by turning it or turn when you supply electricity to it, a speaker can generate electricity (audio signals) or use it to make sound. This is how most of the cheezy "Gi-Joe" kids walkie talkies of the 80s worked (the speaker was also used as the mic). Usualy when you do this, the audio sounds like shit, but it does not matter in your typical low fideli

Re:

[Anonymous Coward]

No my friend, that is a typo in the original article, and the author just copy/pasted it here. In the video they say clearly hat the sound is generated by the speakers.

Re:

[dbIII]

It's a piezoelectric crystal and can both generate sound when a current is applies or generate current when vibrated by a sound.

My dog will hate this

[NavyNasa]

How will dogs feel about this?

Re:

[Anonymous Coward]

Probably how I feel when I hear my neighbor's dogs barking during the night for no good reason when I'm trying to sleep: not too pleased at all!

Or probably how I feel when I have to walk around feces that dogs have deposited all over the sidewalk: not too pleased at all!

Or probably how I feel when I have to visit somebody's house and their dog slobbers all over me and leaves dog hair all over the place: not too pleased at all!

Or probably how I feel when I hear in the news that yet another dog attacked a you

Re:Battery life? Interference? Audible artifacts?

[Hognoxious]

supersonic sound

Yo dawg, i herd u like fast sound, so I put more speed in ur sound so ur sound is faster than sound which is faster than sound which is faster than sound which is faster than sound which is faster th
stack size exceeded. Baling out near line 214137.

butt dialing

[cellocgw]

If this functionality leads to an app which can detect being in a pocket, and defeat dialing when the phone is in a pocket, I'm all for it.

Re:

[Xenx]

You act like the technology is flawless. It isn't. For me, It's unreliable enough that I have to be careful when using it. But that all comes down to different factors. Like against my cheek, placement of the phone often doesn't block enough light to consistently disable the display. The even more annoying one for me is that the light sensor will often prevent me from turning the screen on to check messages. My hand isn't directly on the light sensor, but blocks enough to prevent me turning it on.

Re:

[Xenx]

Yes, because multiple phones from multiple manufacturers all suck. It's a usability issue. I have to find the sweet spot for it to turn off the display. If I move the phone up or down a bit, it's likely to get enough light to activate.They cannot accommodate everyone all the time. And for what it's worth.. Nexus 6, Nexus 6p, HTC M8 for sure. I also had a Note 2, and an LG Optimus G Pro. I can't vouch for those, as it's been a few years.

What now???

[Ecuador]

The app emits a high-frequency ultrasound tone from the device's existing microphone

I checked, for once it is not an error in the summary, the error is in the actual article.

Anyway, it should be "speaker", the microphone is used to pick up the sound to detect any tone shifts that would indicate pressure on the phone. I highly doubt that this is not very dependent on the construction of the phone, but who am I to doubt "batphone" technology...

Re:

[drinkypoo]

I highly doubt that this is not very dependent on the construction of the phone, but who am I to doubt "batphone" technology...

I'm quite sure that it is, but presumably this could be solved by a calibration stage. Getting that right is probably the hardest part of the whole process...

Batphone? Kids these days

[OzPeter]

In my day a Batphone was a big red phone that sat under a glass dish, and instead of a dial* it had single pushbutton. And when you pressed that button the Batphone on the other end started glowing and beeping in order to indicate an incoming call. That's a Batphone.

* A long time** ago telephones used to have rotary dials with all the digits 0 to 9 spaced around them with each digit associated with a finger sized hole. In order to make your phone call you would dial*** your number digit by digit. This involved placing your finger in the hole associated with the digit and rotating the complete dial clockwise until you reached the finger stop. At this point you would remove your finger and the dial would return to its original position. During the return phase the phone would issue a series of audible clicks, with the number clicks issued being calibrated to the digit that was dialed. These clicks were transmitted to the phone company and encoded the digit that was dialed.

** An even longer time ago telephones didn't even had dials. Instead they used voice activation (in a manner similar to Siri or Cortana or Echo, but implemented like Amazon's Mechanical Turk EG in a distributed manner) in order to complete your phone call. EG "Operator, connect me with ...."

*** Anachronism alert. Even though modern phones do not have rotary dials, us people with onions on our belts still "dial numbers"

Sounds like a bad idea...

[Anonymous Coward]

What about hearing damage? Inaudible is subjective. I can clearly hear 18kHz. I feel pain when near anti deer and anti cat devices that work similarly. Small children could have their hearing damaged and experience pain or anxiety from this. About time people agree to leave 16kHz to 25kHz frequencies alone. They are NOT inaudible to everyone.

Sound Science Says No

[nintendoeats]

Given the limitations of a cell phone for audio, I sure hope that the engineers haven't wasted energy making them emit and detect frequencies outside the true range of human hearing. 18 Khz is still well within audibility for many people.

Alternative uses

[JustAnotherOldGuy]

"This gives users an additional way to interact with their device through the app alone."

Translation:

"This gives advertisers an additional way to collect data on people that they'll never suspect."

But I can hear things...

[bobmajdakjr]

I would like to try one of these apps in my hand. I often hear high painful things designed to do shit like scare away bugs and birds that others around the city cannot. Even went to a few city council meetings to get some of them removed so I could walk down the street from my apt. Some of them are more of a feeling where I know its going on and it just feels odd (dog whistles), but some of them are pain stabs in all my face holes.