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Phased Array Microphone (2023)

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Re: Phased Array Microphone (2023)

#111

Post by t0mas88 »

entropicdrifter wrote: post #38
frankus wrote: post #15

"As part of the calibration, the speed of sound is also a parameter which is optimized to obtain the best model of the system, which allows this whole procedure to act as a ridiculously overengineered thermometer." Reminds me of the electronics adage: "all sensors are temperature sensors, some measure other things as well."

It does act as a thermometer, if and only if the altitude remains constant. The speed of sound fluctuates with both temperature and altitude

The speed of sound fluctuates with density. Altitude and temperature both change density.

Re: Phased Array Microphone (2023)

#112

Post by biot »

immibis wrote: post #87
sitkack wrote: post #84

Earlier quoted context omitted.

All diodes are also light SENSING is you try hard enough.

You don't have to try hard. Just use it as a photodiode and it magically works. However, if it's inside a plastic case that blocks light, it doesn't. Due to some law about entropy, efficient processes are necessarily reversible. That's why electric motors - some of the most efficient machines ever invented - are also generators.

> However, if it's inside a plastic case that blocks light, it doesn't.

You want an ordinary diode to allow current to flow easily when it senses light? Simple: shine a powerful laser at the plastic-encased diode and it will melt the plastic and liquify the metal, fusing it together and allowing current to flow again. See? You just needed to try harder.

Re: Phased Array Microphone (2023)

#113

Post by danielheath »

frankus wrote: post #15

"As part of the calibration, the speed of sound is also a parameter which is optimized to obtain the best model of the system, which allows this whole procedure to act as a ridiculously overengineered thermometer." Reminds me of the electronics adage: "all sensors are temperature sensors, some measure other things as well."

Back in high school, I built (with some parental assistance) an apparatus to measure how quickly the pressure would drop (in a pressurized cylinder) when a very small hole allowed air to leak out.

Turns out, not only can you measure temperature that way, but can extrapolate the graph out to find absolute zero (IIRC my result was out by about 20 kelvin, which I think is pretty damn good for a high-school-garage project).

Re: Phased Array Microphone (2023)

#114

Post by crote »

elictronic wrote: post #34
crote wrote: post #4

I'm a bit surprised by those long "arm" PCBs. They are already doing calibration to account for some relatively large offsets: why not place each sensor on its own PCB, mount them to some carrier structure, and let calibration deal with the rest?

Pcb manufacturing is cheap. I put 20 parts 1.5 inch by 24 inch into pcbway and ended up with final delivered cost of 240 dollars. Not having to deal with wiring that many individual boards and all days of headaches tracking down issues is well worth it in my book.

Huh, you're right. I expected 24-inch-long PCBs to be quite a bit more expensive, but even 4-layer boards at those sizes are still available at discount prices. I guess such thin boards could be used to fill in edges of mixed-order panels? It does make me wonder why they say "the array" was $700. Maybe assembly was extremely expensive

It doesn't seem they weren't really able to benefit from it all that much, though: half of them arrived defective, and they had to do quite a lot of debugging to fix them.

Re: Phased Array Microphone (2023)

#115

Post by sitkack »

hinkley wrote: post #42
amelius wrote: post #2

Nice. It would be cool if this project could cleanly separate sources based on location. That would be a bit like a lightfield camera, where you can edit the focusing parameters after the image has already been taken, but now with sound. https://en.wikipedia.org/wiki/Light_field_camera

I’m still sad these didn’t become a thing. I don’t need a 48MP camera phone. No seriously. I do not.

If you can get a microlens array infront of that 48MP imager, you can have the light field camera you seek.

Re: Phased Array Microphone (2023)

#116

Post by sitkack »

Salmonfisher11 wrote: post #26
spankalee wrote: post #14

Earlier quoted context omitted.

I've always wanted this for videoconferencing room. A microphone array around the screen should be able to dynamically focus on the active talkers and cancel out background noise and echos to get much better sound quality that the muddy crap we usually get. If there were a speaker array around the screens too, you might be able to localize the audio for each person so that it seems like the sound is coming from where…

Beamforming is standard in modern conference room gear. It's being used for making a video focus on the active speaker and optimizing his audio. Have a look at the "Meeting Owl" for example. It works great up to a limit (around 5m) then you will need additional microphones closer to the speaker.

XMOS targets this space specifically.

https://www.xmos.com/ a descendant of the Transputer.

Re: Phased Array Microphone (2023)

#117

Post by sitkack »

immibis wrote: post #87
sitkack wrote: post #84

Earlier quoted context omitted.

All diodes are also light SENSING is you try hard enough.

You don't have to try hard. Just use it as a photodiode and it magically works. However, if it's inside a plastic case that blocks light, it doesn't. Due to some law about entropy, efficient processes are necessarily reversible. That's why electric motors - some of the most efficient machines ever invented - are also generators.

All diodes are photodiodes, one has to be esp careful of glass encapsulated diodes. I have had that bite me before.

Re: Phased Array Microphone (2023)

#118

Post by billyjmc »

adrianmonk wrote: post #69
__MatrixMan__ wrote: post #31

Earlier quoted context omitted.

I wish could rent one to figure out which device in my office has a squealing capacitor. I can hear it well enough to be driven crazy by it, but not well enough to find it. I start disconnecting things to narrow it down but then convince myself that it's my ears ringing. I'm unsure if I'll age out of this problem, or if worse hearing will just recreate it at different thresholds.

You might have some luck with a spectrum analyzer app[1]. A fixed-pitch whine should show up as a line on the waterfall graph. If you move the phone around to differently locations, you might see the line getting stronger or weaker. You can also try rotating the phone to different orientations to see if it is coming from a particular direction. I used this to locate an annoying squeal coming from some equipment at wo…

Phyphox is a great sensor suite app for undergrad Physics experiments, and it includes a spectrum analyzer. Also, it supports both iOS and Android.

Re: Phased Array Microphone (2023)

#120

Post by dleary »

redblacktree wrote: post #99
lscharen wrote: post #67

Earlier quoted context omitted.

Reminds me of Intellectual Venture's Optical Fence developed to track and kill mosquitoes with short laser pulses. As a side-effect of the precision needed to spatially locate the mosquitoes, they could detect different wing beat frequencies that allowed target discrimination by sex and species.

Where can I buy one?

This laser mosquito killer is, and always has been, a PR whitewashing campaign for Intellectual Venture's reputation.

This device has never been built, never been purchasable, and it is ALWAYS brought up whenever IV wants to talk about how cool they are.

And I say this as someone who loosely knows and was friends with a few people that worked there. They brought up this same invention when they were talking about their work. They eventually soured on the company, once they saw the actual sausage being made.

IV is a patent troll, shaking down people doing the real work of developing products.

They trot out this invention, and a handful of others, to appear like they are a public benefit. Never mind that most of these inventions don't really exist, have never been manufactured.

They hide the extent of their holdings, they hide the byzantine network of shell companies they use to mask their holdings, and they spend a significant amount of their money lobbying (bribing).

Why do they need to hide all of this?

Look at their front page, prominently featuring the "Autoscope", for fighting malaria. Fighting malaria sounds great, they're the good guys, right? Now do a bit of web searching to try to find out what the Autoscope is and where it's being used. It's vaporware press release articles going back 8 years.

Look at their "spinouts" page, and try to find any real substance at all on these companies. It is all gossamer, marketing speak with nothing behind it when you actually go looking for it.

Meanwhile, they hold a portfolio of more than 40,000 patents, and they siphon off billions from the real economy. Part of their "licensing agreement" is that you can't talk badly about them after they shake you down, or else the price goes up.

They are rent-seeking parasites.

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