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Guitar tuner that uses phone accelerometer

tautme.github.io

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Re: Guitar tuner that uses phone accelerometer

#51

Post by MomsAVoxell »

pc86 wrote: post #42
Akuehne wrote: post #24

This has some very interesting privacy and security risks. If the tech can do more complex frequency analysis, then couldn't it essentially be used as a microphone for a device that doesn't need permission.

It's a pretty well-known exploit that the CIA is capable of turning a lot of electronics with speakers into microphones. I imagine there is an entire classified backlog of things they can turn into microphones without the target's knowledge.

The accelerometers that protect the average hard drive are easily subverted for this purpose.

Re: Guitar tuner that uses phone accelerometer

#52

Post by nerdsniper »

righthand wrote: post #46
pc86 wrote: post #42

Earlier quoted context omitted.

It's a pretty well-known exploit that the CIA is capable of turning a lot of electronics with speakers into microphones. I imagine there is an entire classified backlog of things they can turn into microphones without the target's knowledge.

The CIA…plug a set of regular headphones into a microphone jack, open a recording application and speak into the headphone speaker, you don’t need a 3 letter agency for that physics open secret.

Wouldn't you need to rewire the headphones? Headphones use a 3-pin TRS whereas a 4-pin TRRS plug is used when you add a microphone. Regardless if the 4-pin is CTIA or OMTP, it's generally only going to get shorted to ground if a 3-pin TRS plug is plugged into a 4-pin TRRS socket, or if a 4-pin TRRS plug is plugged into a 3-pin TRS socket.

Diagram: https://i.sstatic.net/8rSD2.jpg

Re: Guitar tuner that uses phone accelerometer

#53

Post by kps »

nerdsniper wrote: post #52
righthand wrote: post #46

Earlier quoted context omitted.

The CIA…plug a set of regular headphones into a microphone jack, open a recording application and speak into the headphone speaker, you don’t need a 3 letter agency for that physics open secret.

Wouldn't you need to rewire the headphones? Headphones use a 3-pin TRS whereas a 4-pin TRRS plug is used when you add a microphone. Regardless if the 4-pin is CTIA or OMTP, it's generally only going to get shorted to ground if a 3-pin TRS plug is plugged into a 4-pin TRRS socket, or if a 4-pin TRRS plug is plugged into a 3-pin TRS socket. Diagram: https://i.sstatic.net/8rSD2.jpg

Non-phone non-Apple devices often have a TRS microphone input separate from the TRS headphone output.

Re: Guitar tuner that uses phone accelerometer

#54

Post by sandworm101 »

MomsAVoxell wrote: post #51
pc86 wrote: post #42

Earlier quoted context omitted.

It's a pretty well-known exploit that the CIA is capable of turning a lot of electronics with speakers into microphones. I imagine there is an entire classified backlog of things they can turn into microphones without the target's knowledge.

The accelerometers that protect the average hard drive are easily subverted for this purpose.

There is something better. The little sensor that maintains the distance between the spinning platter and the armature is sensitive enough to be a reasonable microphone. But it is inside a heavy metal box (the HDD) so you do need to shout at it.

https://physics.aps.org/articles/v12/24

>> They tapped into the feedback system that helps control the position of the read head above the magnetic disk. When the head is buffeted by sound waves, the vibrations are reflected in the voltage signal produced by the drive’s position sensors. By reading this signal, Fu and his colleagues were able to make high-quality recordings of people speaking near the drive.

Re: Guitar tuner that uses phone accelerometer

#57

Post by foobarian »

dehrmann wrote: post #56

The more reliable guitar tuners do something like this. You clip them on the neck, and they detect vibrations in the wood rather than from sound in the air.

Violin/other strings tuners tend to have this mode for orchestra uses with many people next to you also making sounds.

Re: Guitar tuner that uses phone accelerometer

#58

Post by soperj »

dehrmann wrote: post #56

The more reliable guitar tuners do something like this. You clip them on the neck, and they detect vibrations in the wood rather than from sound in the air.

oddly, this is how I learned to tune my guitar. I'm pretty tone deaf, but can feel the difference between the reference string and the string I'm trying to tune through the guitar.

Re: Guitar tuner that uses phone accelerometer

#59

Post by jjk166 »

Akuehne wrote: post #24

This has some very interesting privacy and security risks. If the tech can do more complex frequency analysis, then couldn't it essentially be used as a microphone for a device that doesn't need permission.

I doubt the sampling rate is anywhere near what you would need to make out dialog in a sound recording. You might be able to tell who is speaking though if you had a voice profile.

Re: Guitar tuner that uses phone accelerometer

#60

Post by DANmode »

weard_beard wrote: post #27
Akuehne wrote: post #24

This has some very interesting privacy and security risks. If the tech can do more complex frequency analysis, then couldn't it essentially be used as a microphone for a device that doesn't need permission.

Sounds like you've got a great idea for a proof of concept for DefCon next year...

Probably worth reviewing prior art for inspiration:

0) https://www.usenix.org/conference/usenixsecurity14/technical...

1) https://infocondb.org/con/black-hat/black-hat-europe-2014/gy...

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