Jump to content

Sign in to follow this  
ThirdDrawerDown

Integrating a telescope [light bulb moment] - advice

Recommended Posts

Posted (edited)

Many people on SNA like to keep abreast of the latest research and discoveries and one of the more interesting recent announcements comes from an Israeli University. Their researches have literally delivered me with a light bulb moment. As a result I am seriously reconsidering my system design.

 

Because this is at the cutting edge of audio I am having some trouble working from first principles to integrate the telescope into the signal path and thought the SNA brains trust would be onto this and able to provide some guidance.

 

I better explain. Here is the advice. It explains things better than I could. Please excuse the length of the quote from Wired via Ars Technica.

 

Quote

The list of sophisticated eavesdropping techniques has grown steadily over years: wiretaps, hacked phones, bugs in the wall—even bouncing lasers off of a building's glass to pick up conversations inside. Now add another tool for audio spies: Any light bulb in a room that might be visible from a window.

 

Researchers from Israeli's Ben-Gurion University of the Negev and the Weizmann Institute of Science today revealed a new technique for long-distance eavesdropping they call "lamphone." They say it allows anyone with a laptop and less than a thousand dollars of equipment—just a telescope and a $400 electro-optical sensor—to listen in on any sounds in a room that's hundreds of feet away in real-time, simply by observing the minuscule vibrations those sounds create on the glass surface of a light bulb inside. By measuring the tiny changes in light output from the bulb that those vibrations cause, the researchers show that a spy can pick up sound clearly enough to discern the contents of conversations or even recognize a piece of music.

 

"Any sound in the room can be recovered from the room with no requirement to hack anything and no device in the room," says Ben Nassi, a security researcher at Ben-Gurion who developed the technique with fellow researchers Yaron Pirutin and Boris Zadov, and who plans to present their findings at the Black Hat security conference in August [2020]. "You just need line of sight to a hanging bulb, and this is it."

 

In their experiments, the researchers placed a series of telescopes around 80 feet away from a target office's light bulb, and put each telescope's eyepiece in front of a Thorlabs PDA100A2 electro-optical sensor. They then used an analog-to-digital converter to convert the electrical signals from that sensor to digital information. While they played music and speech recordings in the faraway room, they fed the information picked up by their set-up to a laptop, which analyzed the readings.

 

The researchers found that the tiny vibrations of the light bulb in response to sound—movements that they measured at as little as a few hundred microns—registered as measurable changes in the light their sensor picked up through each telescope. After processing the signal through software to filter out noise, they were able to reconstruct recordings of the sounds inside the room with remarkable fidelity: They showed, for instance, that they could reproduce an audible snippet of a speech from President Donald Trump well enough for it to be transcribed by Google's Cloud Speech API. They also generated a recording of the Beatles' "Let It Be" clear enough that the name-that-tune app Shazam could instantly recognize it.

 

The technique nonetheless has some limitations. In their tests, the researchers used a hanging bulb, and it's not clear if a bulb mounted in a fixed lamp or a ceiling fixture would vibrate enough to derive the same sort of audio signal. The voice and music recordings they used in their demonstrations were also louder than the average human conversation, with speakers turned to their maximum volume. But the team points out that they also used a relatively cheap electro-optical sensor and analog-to-digital converter, and could have upgraded to a more expensive one to pick up quieter conversations. LED bulbs also offer a signal-to-noise ratio that's about 6.3 times that of an incandescent bulb and 70 times a fluorescent one.

 

An immediate first step of course is in relation to wattage. From now on when someone talks to me about wattage, I'm going to have to ask if they are referring to amplifier wattage or light bulb wattage. For example hereabouts we are looking at a 2 x 375 watt combo, this is serious hi-fi, except it's infra-red and being installed in the bathroom ceiling as part of the renos, which means that the best listening position is not where the seat is.

 

Then there's the telescope question. Does that mean monaural? Are binoculars a better option to provide depth of field and soundstage?

 

How does one ensure good imaging? Should the telescope be fastened to the floor or completely decoupled by way of anti-vibration mounts etc. I think I'm going to have some real-life results for you, as in order to get the light bulb/ telescope signal path working properly I have no option but to put the telescope in the middle of the laundry floor. WAF has suddenly become a critical factor, and a dim view is being taken about limiting the times when the washing machine operates to periods when the stereo is off.

 

This research looks to be a positive contribution to civilization and in particular to audio technology. Given the nature of the research I can only assume that the research was sponsored by Mossad, and if so, this is a very good thing! Secret services get a bad rap, last news I heard about Mossad was they used New Zealand passports for an assassination in the Gulf, which really raised the question of "if that's how you treat your friends..." So sharing this cutting-edge audio news is certainly a step in the right direction.

 

Currently I'm looking at a pair of these, because non-spherical light bulbs might have a profound effect on the algorithms, such as loss of bass. Obviously I've taken the clear option for transparency.

 

4WattG150AmberSpiralDimmableLEDFilamentB

 

 

 

 

Edited by ThirdDrawerDown
fixed the quote

Share this post


Link to post
Share on other sites
4 minutes ago, ThirdDrawerDown said:

I better explain. Here is the advice. It explains things better than I could

Wow... that's pretty cool.   Comodity measuring/data processing is pretty impressive these days.

 

Also, quite scary for privacy.

Share this post


Link to post
Share on other sites

Everything is pretty much OK with some one listening in, so long as you don't turn on the light!

So work in the dark, most of us here do that normally don't we?

 

The listening in to another persons system whilst interesting however difficult it may be, say with a 7.1 HT system, how do you manage to get them to provide the music you prefer?

Share this post


Link to post
Share on other sites

The technology will be outdated with the move from light globes to LED bulbs.  

 

Share this post


Link to post
Share on other sites


18 hours ago, ThirdDrawerDown said:

LED bulbs also offer a signal-to-noise ratio that's about 6.3 times that of an incandescent bulb and 70 times a fluorescent one.

from the article.

Share this post


Link to post
Share on other sites
18 hours ago, ThirdDrawerDown said:

An immediate first step of course is in relation to wattage. From now on when someone talks to me about wattage, I'm going to have to ask if they are referring to amplifier wattage or light bulb wattage.

 

Yes, and distance of the listener to the light bulb is to be measured as whattage.

 

FYI, LED's don't sound as warm.

Share this post


Link to post
Share on other sites

The important thing to remember is that telescopes are most definitely directional.

Share this post


Link to post
Share on other sites

Neighbors dont need a telescope to know l am playing Deep purple at the moment.

 

regards Bruce

Share this post


Link to post
Share on other sites


Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Sign in to follow this  

  • Classifieds Statistics


    Currently Active Ads

    Total Sales (Since 2018)

    Total Sales Value (Last 14 Days)

    Total Ads Value (Since March 2020)
  • Recently Browsing   0 members

    No registered users viewing this page.

  • Similar Content

    • By getdisdude
      Item: Samsung Series 7 55" TV
      Location: Melb
      Price: Withdrawn.
      Item Condition: Excellent Condition
      Reason for selling: Upgrade
      Payment Method: Pickup - Cash, Paypal, COD Only
      Extra Info: This is actually a really good TV, the older samsungs really ruled the TV world before OLED. 
       
      TV in excellent condition no scratch or marks and comes with remote - no Box sorry! Pick up St Kilda Road
       
      Pictures:
       
       




    • By antik
      Selling my Samsung 40" Series 6 LED TV due to upgrade. Model UA40C6900.
      Has been working flawlessly over the years and it has seen very little usage as I don't watch much TV at all, only a bluray here and there.
      It has been professionally calibrated by Avical Australia (http://www.avical.com.au/) so you know you're getting the utmost best picture quality.
      This calibration cost $400 and trust me, it was worth every cent.
      Comes with remote, detailed calibration report and ultra-slim wall mount kit (similar to this: http://www.samsung.com/us/televisions-home-theater/television-home-theater-accessories/televisions/ultra-slim-wall-mount-wmn3000bx-za/).
      I think I have a spare HDMI cable floating around somewhere which I'll also include.
      Looking for $500
      Pickup from 3072


    • By BMC Audio Visual
      Item: Sim2 NERO 3 DLP Projector
      Location: Burwood VIC
      Price: $11,995
      Item Condition: NEW Shop display model in "as new" condition with less than 100hrs lamp use
      Reason for selling: We need to say goodbye to this special projector to make room for new models
      Payment Method: Pickup - Cash, Paypal, COD Only
      Extra Info:
      This SIM2 punches above its weight. This projector will give most 4K models a run for their money with its high-quality picture. The Nero 3 will enhance your home entertainment experience with images that are bright, sharp and beautifully realistic. It's made in Italy and as such has European tuning, ie natural yet vivid color, smooth movement and motion. You simply forget the technology and become engrossed in the picture quality and enjoy every moment that you are watching it. You are welcome to see it working. The unit is sold as new and with full 2 year warranty. This is a $20K projector and at $11,995 is a genuine bargain for the right buyer.
       
      LED is the source of illumination with 1-chip DLP image technology. This combination ensures that images are bright, sharp and very realistic. Full 1080p resolution that rivals cheaper 4K projectors images.
      With a specification list that reads: 1,400 lumens of light output (the equivalent of 2,000 lumens on lamp-based projectors), a 30,000:1 contrast ratio and a color gamut 135% that of the NTSC TV standard, this is an impressive projector. The typical application for the Nero 3 is medium/large home theatres and family rooms with moderate ambient light.
       
      INSTALLATION
      Lens Throw ratio NERO 3 1.51-2.88:1 (+/-5%) Lens shift V +/-60% / H +/-10% Digital keystone adjustment Vertical and Horizontal Picture size (inches diagonal) 65-200 Aspect ratio 4:3, 16:9 Anamorphic, LetterBox, panoramic, pixel to pixel + 3 custom-user adjustments  
       
      Pictures:

       
       
    • By @BenQ Australia
      Review: BenQ GS1 Portable LED Projector
      by Kelly Ainslie | Sep 29, 2017

      Why the BenQ GS1? Well, compared to what I was doing 2 years ago, the new BenQ GS1 is an amazing piece of kit, not just its size but how easily and how many different methods to watch content; from wireless streaming, direct HDMI and memory sticks and/or cards.

      Let me paint a mental picture; I started to take a data projector camping to have “movie nights under the stars” with our camping buddies, as this would be fun and good entertainment for the group while we camped in the middle of central Australia away from internet and mobile phones. This sounds simple enough, but when you break down what needed to happen, it actually wasn’t as easy as it seems. I needed to:
       
      1. Power the 240VAC 200W projector for at least 2 hours; I have a 1600 watt inverter in my camper and 240 A/H of Lithium batteries, not everyone has this.
       
      2. The old projector had speakers but not very loud so I need to make them louder, there wasn’t a headphone output jack and I typically use my Apple TV as a media player because I either use my iPad or laptop. So I turned to eBay and purchased $15 HDMI / audio splitter, it passed through the HDMI and had a 2.5mm stereo plug out, then I needed a few HDMI cables to patch in the HDMI audio splitter and a male to male 2.5mm stereo lead to take the audio to an external speaker.
       
      3. Provide a movie source, as I said earlier I would typically use an Apple TV to display from my iPad or Laptop as both didn’t have HDMI out, I would setup a hotspot network on my phone and wirelessly stream* the media…..
       
      4. Having some way of propping up the projector to keep it and everything else out of the dirt which was normally the box that I kept the projector in, balanced precariously on my small foot step from the back of the 4WD.
       

      Old Setup: So many cables!
       
      This all works to some degree of success but it was cumbersome to transport and needed a bit of time to setup and put away after the movie.

      So I hit the web to see what was out there in battery powered, LED, Wireless projectors and BAM! BenQ have made it, it was an OMG moment.

      I had to have it, it was early 2017 and I wasn’t available in Australia yet so I had to make do with the old setup for 6 more months. After being in regular contact with BenQ it finally hit the shelves in late July/August.

      My first impressions when I received the GS1 was that the packaging was basic but strong; a simple unbleached brown box with minimal packing and plastic (which I thought was really good as companies tend to over pack their products in so much plastic that is ultimately thrown into landfills) with the projector inside the padded black travel case and well protected.

      The overall build quality was great and felt strong and the included accessories were good too, it came with the padded bag, an IR remote, HDMI cable, silicone cover, slide on external battery, power pack/charger, small metal threaded insert (I’ll come back to this) and the instruction manual.
       
      The connection ports that could be seen were a Micro SD reader, HDMI, USB 2, USB 3 and from the manual says it has Bluetooth and Wi-Fi which I later found it supported DLNA, Miracast and Airplay* to some degree via apps as it is a full Android mobile operating system, WOW!

      Setup and configuring was simple, I just slide on the battery pack, slipped it in to the silicone boot and pressed the power button and it fired up to the setup screens that stepped me through the usual stuff like country, language, Wi-Fi network etc.
       
      Navigation was simple with the IR remote; it was like using an Apple TV with onscreen keyboard to click each letter at a time. Since it has Bluetooth I quickly found the BT setup menu and I connected a keyboard with track pad and from there it was a snap to navigate and enter info, search the web.

      The HDMI connection worked as expected and during my testing I trialled direct connecting from Surface Pro3, iPhone/iPad via apple HDMI adapter, Surface Pro via wireless HDMI adapter and my modified 12VDC powered Apple TV using an Ad-HOC Wi-Fi network and they all worked fine.
       
      I discovered the app store and downloaded VLC player and Kodi, with these apps I could attach a wireless HDD and my Surface Pro as a server and stream directly to the GS1, and it was awesome. I did find Kodi worked better than VLC player. Having access to apps I’m sure there are others for wireless media platforms*

      I also downloaded an MP4 movie to a micro SDHC card and USB stick both options work perfectly too. My preference was the Micro SD card as it didn’t stick out and potentially break off if knocked.
       
      The audio was ok, for the 2 x 2watt speakers in a small room, tent or caravan it would be fine, for open air it needed a bit more punch and the Bluetooth connectivity was just the trick, I paired it with my Bose mini soundLink and boom the movie came alive.
       
      I was keen to trial the tripod setup shown on the web and this wasn’t as good as all the other features so far. To mount the projector with the battery installed you need to use this threaded insert and slide it into a keyway slot on the bottom of the battery but it stayed proud of the battery so the projector wouldn’t sit properly on the QR plate and flopped around. Basically to get the projector to sit flat and firm I had to cut and drill a piece of plastic to make a spacer. This worked really well but makes me wonder if this was an after-thought! The projector is designed to be used with the battery but there is no permanent tripod screw, whereas the projector itself does have a permanent tripod screw.
       

      New BenQ setup: No cables!

      There were a few little things that I think need to be addressed for the second version and will most likely be a natural path, so I don’t want to discourage anyone thinking of this unit.

      Improvements:
      Micro SDXC support, at the time I tested the GS1 I used a 32gb Micro SDHC card which worked fine, I also tried a 128gb Micro SDXC card that I had permanently inserted in my SurfacePro3 which is where I store my movie content, the GS1 didn’t recognise it. Maybe next release version or firmware update?

      A battery switch physically to turn the power off to the GS1; if the GS1 projector and battery stayed connected together the unit could only be put into standby (not fully off) and in theory if you bumped the standby button on top on the unit would cause it to start-up, possibly in the travel case and run flat.

      A permanent and flush tripod screw mount built-in/moulded into the base of the battery. (This was my biggest and most annoying issue with the projector)
       

       
      Dual Bluetooth speaker support, this is not a problem but a wish list item. Presently you can only connect 1 pair of Bluetooth headphones. My thoughts are as a couple, the two of you may want to use the projector with headphones while camping or caravanning, because you don’t want to annoy the surrounding campers with explosions from the movie sound track. Sure you could use the wired headphone output through a splitter but then we are going back the bad old days. Another benefit of dual Bluetooth would be when having a large group movie night multiple BT speakers spread around the group would be awesome. Just an idea ;).

      In summary the projector is very awesome (accept for the battery tripod screw thing), it was simple to use with all of the modern connection methods one would want, plus it had the added advantage of apps because of the Android OS. I would totally recommend this product in its current version as it there isn’t anything that has these features, quality and convenience for the price. I would rate it at 4.5 thumbs up and/or 90%, this allows BenQ room to improve.
       
      *Airplay support by 3rd party Apps
    • By @BenQ Australia
      BenQ Launches GS1 Portable LED Projector
      A Must-Have Portable Entertainment For Both
      Indoor and Outdoor Environments
       
      --
       

      BenQ's GS1 portable LED projector (shown with battery and protective rubber case)
       
       
      Sydney, Australia, 29th September 2017 – BenQ, the global provider of digital lifestyle innovations, announces a new outdoor entertainment solution that will transform camping at night into an experience that you’ll never forget. GS1 will soon become the outdoor camping gear you won’t leave home without!
       
      Andrew Lambkin, Business Development Manager of BenQ Australia commented, “ As camping and outdoor holidays continue to grow in popularity, families are searching for new activities that can help them spend quality time together. The GS1 is the ideal solution, delivering portable entertainment that’s suitable for all ages. We are delighted to launch this new outdoor projector, it’s small enough to fit into any space ensuring it will be part of your essential camping kit.”
        
      Rewrite the Rules
      Streaming online content like movies, music and videos in seconds has never been simpler. You can also use the “BenQ Video Tray” Android phone app and share content directly to your phone. GS1 is a plug and play, palm-sized portable LED projector with built-in USB readers. You will be the envy of other campers and with no cables you can just sit back, relax and enjoy some hassle-free and well-earned downtime. Stream audio to your Bluetooth speakers and listen to truly memorable audio that’s just like a night at the movies. GS1 has a detachable 3-hour battery enough to last the evening. When you need more battery life just swap it out with additional optional batteries and enjoy the rest of your evening – this cable-free solution is perfect for outdoor entertainment.
       

      BenQ's GS1 portable LED projector
       
       
      Impress Your Friends. Entertain in Seconds
      Wherever you set up camp, with a simple one touch power button, GS1 will power up in just 3 seconds– so you can expand your world and entertain friends in style! The hassle-free GS1 portable projector features an intuitive user interface with inputs that enable multimedia entertainment and online streaming. Auto keystone adjusts the image to suit the screen – whether it’s your tent, caravan or motor home. The first time you use it, GS1’s set-up wizard makes it simple for non-technical users to get started and it will save your settings automatically, so the next time you use it you are ready to go! Wherever you set up, the foot can be manually adjusted to suit the height of your temporary screen- the GS1 is ready to go wherever you are.  
       
      Outdoor Camping Gear Designed to Cope with Every Day Family Life
      GS1 has a standard protective rubber case, perfect for families who need a little more protection. Even if it’s accidentally knocked onto the floor, the GS1 with its optional case is drop proof, which means it will even survive a fall of 60cm. What if a drink gets spilt? There’s no need to worry because GS1’s rubberized case is also IPX1 Splash Proof. Unlike other projectors, the GS1 emits low heat making it safe enough for inquisitive children to touch without hurting their hands.
       
       
      BenQ's GS1 - So small it fits into the palm of your hand
       
      So Small You’ll Never Leave Home Without It
      Packing for a camping holiday can be stressful when space is at a premium. GS1 comes with an attractive custom fitted bag designed to carry the projector, battery, protective rubber case, and all accessories. The GS1 (13.9cm x 14.6cm) is small enough to fit into any car trunk or caravan cupboard. Compact but powerful, the GS1 and battery weighs just 1kg and fits into the palm of your hand. With a short throw lens, GS1 can project a 60” image at just one meter, so you won’t upset your camping neighbours for taking up additional space.
       
      Enjoy a Movie Experience That’s Out of This World
      Even in low light, the GS1 will project against your tent, caravan or motorhome and delivers superb image quality every time. GS1 has several picture modes: Camping is the default which is brighter than Movie mode to take into account the light outdoors at night. In addition, there is Vivid mode so when you get home you can use this palm sized projector again and again and adjust the mode with one touch to suit you.
       
      BenQ’s GS1 portable projector is available now for RRP $999. Please visit BenQ’s website for more information.

×
×
  • Create New...