Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

Guitar tuner that uses phone accelerometer

tautme.github.io

Post reply on HN
Print view View original

71–80 of 105 posts

Re: Guitar tuner that uses phone accelerometer

#71

Post by ok_dad »

sandworm101 wrote: post #54
MomsAVoxell wrote: post #51

Earlier quoted context omitted.

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 buf…

The NSA could turn on your flip phones mic thirty years ago without you knowing, I don’t think they needed to do all that fancy stuff with hard drives. That’s just research that they funded to cover up the fact that they owned every computing device on the planet for a while.

Re: Guitar tuner that uses phone accelerometer

#72

Post by adm4 »

tiluha wrote: post #14
adm4 wrote: post #2

guitar detuner that uses accelerometer instead of microphone, it doesn't really work, but amazing to see how sensitive they are.

It really is crazy. Placing my phone on my chest lying down i can clearly see my heartbeat on the graph

good idea https://tautme.github.io/phone-sensors/heartRate.html , try setting it on the ground and see how sensitive it is to foot steps.... or earthquake https://seismosense.com

Re: Guitar tuner that uses phone accelerometer

#73

Post by lightedman »

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

"Wouldn't you need to rewire the headphones?"

This is basic physics controlling the effect here, not electrical routing. Speakers are microphones by their very design. To make them work as a microphone, you merely speak into them with them plugged into an input jack that provides at minimum a line level electrical signal to be modified by wiggling the speaker cone/diaphragm back and forth.

Re: Guitar tuner that uses phone accelerometer

#74

Post by maxbond »

ge96 wrote: post #65
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.

Tangent but the hidden no-electronics bug "The Thing / Great Seal Bug" really crazy

It had no internal power supply, it worked like an RFID tag, but it was electronic.

Tangentially, I didn't know this (from Wikipedia):

> The Thing was designed by Soviet Russian inventor Leon Theremin, best known for his invention of the theremin, an electronic musical instrument.

Re: Guitar tuner that uses phone accelerometer

#75

Post by lightedman »

recursive wrote: post #62
nubinetwork wrote: post #18

This sounds neat, but I think I owned a tuner for about 6 weeks before I could do it by ear... EADGBe isn't that hard.

So what do you do when the lead singer is engaging in some stage banter and you need to tune between songs? IEMs? With what reference pitch?

A good chunk of us are in tune (pun intended) with our instruments to the point that we can simply feel the vibrations and know where we are with regards to tuning.

I haven't touched a tuner in about half a decade.

Re: Guitar tuner that uses phone accelerometer

#76

Post by ge96 »

maxbond wrote: post #74
ge96 wrote: post #65

Earlier quoted context omitted.

Tangent but the hidden no-electronics bug "The Thing / Great Seal Bug" really crazy

It had no internal power supply, it worked like an RFID tag, but it was electronic. Tangentially, I didn't know this (from Wikipedia): > The Thing was designed by Soviet Russian inventor Leon Theremin, best known for his invention of the theremin, an electronic musical instrument.

Yeah I was going for no battery

Idk though when I read it, it seems like it's literally an antenna attached to a can "resonator" is that electronics? It is I guess since it can carry an RF wave? Electronics I think of a chip or circuitry. I get it has to be some form of a circuit to work even as a monopole.

The article says it though: "...hung in his office behind his desk, and which contained an electronic device"

Re: Guitar tuner that uses phone accelerometer

#77

Post by recursive »

lightedman wrote: post #75
recursive wrote: post #62

Earlier quoted context omitted.

So what do you do when the lead singer is engaging in some stage banter and you need to tune between songs? IEMs? With what reference pitch?

A good chunk of us are in tune (pun intended) with our instruments to the point that we can simply feel the vibrations and know where we are with regards to tuning. I haven't touched a tuner in about half a decade.

That sounds like a very useful skill for a working player. But it seems to come with a couple of significant conditions.

I can believe this is possible. But I don't think this is a reasonable thing as a baseline expectation for a player with 6 weeks of experience, which was the original comment in this thread.

I don't know the details, but I imagine you're feeling beats transmitted through the neck or something. But if that is the case (an assumption) it still requires you to have at least one known-good string, unless you're playing solo.

So, for these circumstances, and others, a pedal-based or clip-on headstock tuner seem like they still have plenty of practical application.

Re: Guitar tuner that uses phone accelerometer

#79

Post by soperj »

adzm wrote: post #63
DANmode wrote: post #61

Earlier quoted context omitted.

This is fascinating. Thanks for sharing.

The beat frequencies are pretty noticable, just tune until they go away

That's the terminology I was looking for. Didn't know whether to tune up or down without changing frets, could tell when it was right though.

Re: Guitar tuner that uses phone accelerometer

#80

Post by maxbond »

ge96 wrote: post #76
maxbond wrote: post #74

Earlier quoted context omitted.

It had no internal power supply, it worked like an RFID tag, but it was electronic. Tangentially, I didn't know this (from Wikipedia): > The Thing was designed by Soviet Russian inventor Leon Theremin, best known for his invention of the theremin, an electronic musical instrument.

Yeah I was going for no battery Idk though when I read it, it seems like it's literally an antenna attached to a can "resonator" is that electronics? It is I guess since it can carry an RF wave? Electronics I think of a chip or circuitry. I get it has to be some form of a circuit to work even as a monopole. The article says it though: "...hung in his office behind his desk, and which contained an electronic device"

I think if you saw it on a bench hooked up to wires, it would be intuitive that it was a circuit. It's equivalent, but instead of being coupled via wires it's coupled via RF. I think it feels like there's no return path and that the circuit is open, but it's a real circuit with complicated/uncommon coupling to the power source.

A resonator is both a component in the circuit (the case is a cavity resonator) and the type of circuit this is. When illuminated (or hooked up to a power supply on the bench), it produces a sine wave, and holding all else equal the frequency is a function of the capacitance of our membrane capacitor. That membrane is flapping about due to sound, changing the distance between the plates of our capacitor and thus it's capacitance. So this shifts the frequency we're resonating at and encodes the audio into our output signal (frequency modulation).

So it's very similar to a standard LC resonator circuit you might make on a breadboard.

I'll leave you with another story of clever KGB sabotage. The KGB controlled facilities used to construct the US embassy in Moscow in 1979. They were able to extensively bug the building. They were also able to mix thousands of diodes into the concrete. This defeated NLJD (https://en.wikipedia.org/wiki/Nonlinear_junction_detector) based bug detection because they detected the diodes in every direction.

Post reply on HN