help me in designing a "voice direction detection" component

hello! i am designing a robot along the many functionalities, one of the hard things to do is its voice direction detection module which would detect direction of the voice of some person, and comes towards the person. Can any one tell me how to design the voice detection module.

Reply to
Dr_PhD
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One thing you might try is mounting multiple mics or transducers on opposing sides of your robot. If the robot is large enough, the mic facing the source of sound will have a greater presence of low frequency sounds.

Just a thought.

Adam

Reply to
Jacobe Hazzard

Maybe combine sound with infrared (humans also emit IR). Standard components, but I admit it will not work if there is more than one warmblooded animal present.

Wim

Reply to
Wim Ton

----------------------------- Little rotating horn made out of two sandwiched disks with radial partitions within that directs sound to a high-gain mic, and its optical circuit knows which way it's pointed, and the mic is amplified to an op-amp rectifier circuit to a small cap, and then a negative slope-detector points the direction. Or a circle of mics in small horns and they compete for loudness.

Or you can use two ears cupped forward on a rotatable head with a pattern of multiple mics in each with partitions in them so that they can sense directionality based on loudness. Make the head turn toward the expected direction from that data and then recalculate and rinse and repeat. Then have the program turn the bot till the head is forward again and it will automatically come to you.

-Steve --

-Steve Walz snipped-for-privacy@armory.com ftp://ftp.armory.com/pub/user/rstevew Electronics Site!! 1000's of Files and Dirs!! With Schematics Galore!!

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Reply to
R. Steve Walz

One possibility is to use the time delay between multiple microphones. Voice wouldn't be the best thing for this, something like a click or other sound with a short attack time. Two microphones would give you the ability to tell the angle the sound is coming from, but not whether it's in front or back of you. Three mics would give enough information to you. The math is non-trivial, but I think it could be easily enough done in a PIC by using a table lookup of precalculated angles from 0-90 degrees.

With a spacing of 1' between two of the microphones, there would be a delay varying from 0 to about 1mS depending upon the angle of incidence of the sound being heard. The third mic is place ahead of or behind the two used for timing measurements. It is used only to tell whether the sound is coming from the front or back. Depending upon which of the two timing mics hear the sound first gives you the right or left component (assuming mikes are placed like ears; one on the left and one on the right.

So now to calculate the angle it's coming from (0 being straight ahead), you look up the delay angle in the table indexed by delay time. Subtract from 360 if the left mic heard it first. Now the tricky part is if the rear mic heard it before either of the timing mics, then you have to mirror the angle back by subtracting it from 180 if the sound came from the right side, or subtracting it from 540 if it came from the left side.

This is off the top of my head, but I think it should work. Someone will correct me if I'm wrong. ;-)

michael

Reply to
Anthony Fremont

I think this may be (but can't absolutely be sure) what you want. Hope your up on your eignenspace matrix analysis. Sure wish I could understand what in the hell they're talking about though ;-)

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Predictably, Hasbro Toys figured out how to accomplish this for a buck and a half

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and another entry into the fray

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There are detection schema other than voice that may be more appropriate for your needs.

"Passive infrared detection refers to the detection of a change in heat in an area or emitted by an object (i.e. body heat). The motion sensors are triggered when the level of heat detected changes from the ambient temperature to a higher or lower temperature."

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Of course, none of the above directly address your request for a schematic or "how to" design procedure but by following the above links and any bibliographies to which they make reference, you just might get lucky.

Google: voice direction detection

Good luck with your project.

Reply to
Baphomet

And immediately after posting, this link for robotic supplies came in on sci.electronics.basic

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Reply to
Baphomet

and one more resource but they are currently off-line

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Reply to
Baphomet

Some more links that may be of interest........ Measure phase difference:

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Speed of sound in humid air calc:

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HTHs Greg the Grog

Reply to
Grog

You might want to try the doppler trick used by radio transmitter detection equipment, for instance radio amateur 'fox hunt' equipment, where they electronically switch between multiple attennas to simulate an antenna fast going around in circles. You mount several non-moving omnidirectional microphones spaced in a circle around the head (say 8 miniature fet mikes pointing upwards). Electronically switch between them so that the 'active' microphone appears to be going in circles. This 'rotation' has to be done considerable slower (say, 10 Hz) than the lowest frequency you are going to monitor. You determine doppler variations by looking for the rotation frequency in the signal. And because you know which direction the virtual microphone is rotating, you can determine the direction of the sound source. But there are considerable complications compared to radio use:

- In radio, you're looking at a single frequency, single source known to be coming from one (unknown) direction.

- With sound, you might have multiple sources, at multiple frequecies each. If you limit the approach to e.g. a (dog) whistle, that might make things very much simpler. I think that in theory this approach might be able to determine the directions of multiple sound sources simultaneously, but you probably have to throw a lot of math and cpu power at it; once you manage that, you likely can split the audio streams so that each source has its own stream.

Mat Nieuwenhoven

Reply to
Mat Nieuwenhoven

Might work okay if you're outside where there are no reflections. But inside, with reflections - lotsa luck.

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Reply to
Watson A.Name - "Watt Sun

Works fine in an anechoic chamber but in a real room where there are reflections off walls this is harder than you can imagine. The reflections can be larger than the original apparently too (non-min phase impulse reponse).

Tom

Reply to
Tom

In a gratuitous crosspost to the following groups:

sci.electr>

Another problem with this is if someone wants to fool a robot by recording voice onto a tape (/minidisc/CDR/mp3 medium) and play it back for the robot on a boom-box or other player. Such an IR detector would be useful, however, as a hint to the robot that it is hearing a voice not attached to a person.

Reply to
Ben Bradley

Like the human ear does: listen to phase differences, the phase between sevaral pickups tells you the direction.

Regards,

Pieter Hoeben

Reply to
Pieter Hoeben

Hi,

Not simple to do unless you are detecting a very short, specific noise.

Theoretically, for such a thing as a voice....

1) Digitize inputs from three sensors in a triangle formation. 2) Compute 'cross correleation' between each pair to find the time differences. 3) Compute a 'solution' for the only source direction that can produce these specific time differences. 4) Write your doctoral thesis with the results.
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Luhan Monat
"LuhanKnows" At 'Yahoo' dot 'Com'
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Reply to
Luhan Monat

why write a thesis on something similar to phased array sonar?

mike

Reply to
Active8

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