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Hand-Mounted Sonar For the Blind 98 writes "The Tacit, a wrist-mounted sonar device with haptic feedback, is like strapping a bat to your wrist to help you see. It makes use of two sonar ping sensors to measure the distance to the nearest obstacle. The relative distance to an object is then fed back to the user using two servos which apply pressure to the back of the wrist."

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Hand-Mounted Sonar For the Blind

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  • by ozmanjusri ( 601766 ) <aussie_bob@[ ] ['hot' in gap]> on Sunday August 21, 2011 @11:15PM (#37164672) Journal
    Well, the bad news is that it's an incredibly ugly watch.

    The good news is that it's users will never know.

  • by Anonymous Coward

    "Like strapping a bat to your wrist to help you see." Somehow that doesn't instill me with confidence in relation to using this product. That sounds like the stupidest idea I've ever heard. Not only do I not see it helping the blind to navigate, but it also sounds like it's extremely unwise :)

    • by Lysander7 ( 2085382 ) on Sunday August 21, 2011 @11:35PM (#37164736)

      You've obviously never heard of Ben Underwood (, whom is often listed among the top ten contemporary inspirational people. Not only was he able to "see" using echolocation via clicking noises with his tongue, he excelled at tasks such as mountain biking. And he is not the last blind person able to do so.

      • by narcc ( 412956 )

        That kid is amazing. Not only can he ride a bike around like any sighted kid, he can also play basket ball incredibly well.

        I recommend anyone unfamiliar go dig up some videos of this kid in action.

        • by jhoegl ( 638955 )
          Yeah, a portion of blind can see via clicking. I watched a documentary on this and the pitfalls of it. Apparently clicking can only let you see on a "2d plane", clicks are only reflective off of objects within your horizon. Meaning that you will not know about sudden drop offs until you fall into them.
          So, because clicking is basically sonar, I am thinking this device has the same fault.
          • I would venture that the 2d limitations of natural human sonar have more to do with the fact that our ears are in a horizontal plane and thus can't distinguish up/down variations. Except in special circumstances, the air through which the sound is travelling is not going to be stratified enough to make a difference.

            Given that, this is likely to sidestep that limitation, since it appears far more directional, and mounted on a hand, which is more natural to tilt than ones head.

            • I always wondered why I looked to the horizon when I heard what I thought was an aeroplane....

              Have you ever actually stepped outside? The variation in sound is amazing once you step away from that techno-crap....

              • Easily justified by the presence of a priori information. You know what an airplane sounds like and that unless you're at an airport, one would hope that it's in the air.

                Simply put, humans are incredible sensor platforms, able to synthesize information from both simple and complex sources. Nonetheless, your ears are essentially two point sensors, so while you can distinguish quite a bit by hearing alone, azimuth by differencing the volume to each ear (of course there's a front-to-back ambiguity), distance

                • by bronney ( 638318 )

                  Dude you ever lived in an apartment sandwiched by 2 Chinese families above and below you? When cooking time comes you can tell which one is chopping just by sitting in your living room.

                • by Linknoid ( 46137 )

                  Yes, the human ear can distinguish vertical position as well. Ever wonder why the outer ear (the pinna) is shaped so weird? It's so it will distort sound coming from different directions differently.

                  Here's an demonstration I saw at the Exploratorium in San Fransisco, but you can easily reproduce this at home.

                  Close your eyes, and have someone standing beside you jingle a ring of keys near your ear, above, below, and adjacent. It's easy to tell where the sound is coming from.

                  Now bend the top cartilage over

                • It is my understanding that your brain takes both the phase difference and the volume difference between the ears in to account when determining the source of the sound. Up/down/front/back are detected by changes in wave form due to the irregular way the ear is shaped.

          • This isn't true, your brain is able to locate the azimuth of a source using spectral differences imparted by the pinna and diffraction artifacts caused by your head and body. This is why HRTF headphones allow you to hear things "over" you and why IMAX and 10.2 speaker systems have speakers above the screen, and not just behind it.

            • Are you saying that the diffraction effects allow one to determine source altitude? Azimuth I would imagine is easily distinguishable from using the ears as mere point sensors, as I mentioned in a sibling post.

              Very interesting. (not saying that sarcastically).

            • by jhoegl ( 638955 )
              I am not going to pretend to know how they see or perceive things around them, but I saw it in the documentary. They went to a small drop off, probably 10 feet, natural in that there was no concrete, and they asked the blind guy if he "saw" it through his clicking. He did not. The reason they were testing him was because they wanted him to carry a cane, something he felt would create empathy for him, something he didnt want.

              Anyways, it is true in the case of the blind.
          • Yes, I saw that documentary too. While his skills were really good, the point was he still needed a cane (although it didn't want to use it, because it would show people that he was blind) Also if you have fast moving objects it could effect your view of the world a fast moving car between clicks can go from well out of your range to about to hit you.

            This skill is a great enhancement to using a cane. However not a full replacement for other services out there, and (at the risk of not being politically co

      • by arose ( 644256 )
        You've obviously never strapped a wild animal onto your wrist.
        • by vlm ( 69642 )

          You've obviously never strapped a wild animal onto your wrist.

          Falconry? At least for outdoor work I'm surprised to have never heard of any avian service animals. Its always "seeing eye dogs" never "seeing eye falcons"


          • Most birds are amazingly stupid and (forgive the pun) flighty. You could, possibly, train a crow or raven to be a useful service animal, but even they lack the degree of control over their defecatory functions that we expect service animals to display.

            • Most birds are amazingly stupid and (forgive the pun) flighty. You could, possibly, train a crow or raven to be a useful service animal, but even they lack the degree of control over their defecatory functions that we expect service animals to display.

              Use a tray. If that is too hard, wear white.

          • by arose ( 644256 )

            More tethered than strapped, not for long, mostly on the forearm and certainly not wild. There's also a thick leather glove involved, so falconry would involve tethering a trained animal to a glove covering the hand and forearm.

            Good effort nonetheless, I didn't think of that.

  • by intellitech ( 1912116 ) on Sunday August 21, 2011 @11:32PM (#37164722)

    And it should've, damnit.

    Keep reading for more information, build notes, parts list, schematics, and code. ...

    Important Note #2: The circuit and software is released under a Creative Commons BY-NC-SA license, which I think of as a "Don't be a jerk" license. In short: Make it, learn from it, teach it, improve it, modify it. Just share what you do, give credit, and don't sell any without contacting me first.

    PARTS LIST?!? CIRCUIT INFO?!? WOOOT! Now this looks like a damn fun toy.

    • by siddesu ( 698447 ) on Monday August 22, 2011 @12:56AM (#37164984)

      I did something similar for my blind dog, which it used for a year before it died earlier this year. I a circuit like this one as starting point: [], and a cheap vibration motor like this one: [], but you can use a parallax PING module or something similar.

      Basically, a controller (I used an atmega chip with an arduino bootloader) that sends pings and moves the motors stronger as the obstacle is closer. Mounted it on the head of the dog, and had the two vibration motors on two sides of the chest. The dog had it figured out in less than a day.

      The only "hard" part is that if you go DIY all the way, you'll need an oscilloscope to build the ultrasonic sensor thing, otherwise it is rather simple.

      • by siddesu ( 698447 )

        I a circuit like this one

        Doh ... I ACCIDENTALY a circuit like this one. The whole thing. Used, I mean.

        • by bronney ( 638318 )

          Dude your correction made it worst now I am so confused :D I can't divide by zero!!!1

      • by anilg ( 961244 )

        Interesting. Did you blog about this by any chance? Pics of it on the dog. I would've thought dogs wouldn't learn a whole new sense.. but they seem to corellate sensor input and the world well enough, according to what you say. I'd be interested in learning more about this..

        • by siddesu ( 698447 )
          No, I don't blog and I do not distribute videos, most of them are too ... unsuitable for distribution. If you want schematics, etc. we can work something out. It wasn't rocket science thing, really, just two buzzers on the pwm outputs and some electronics to measure distance and direction. And it wasn't a "new sense", ever since the dog got deaf and nearly blind it relied mostly on smell and touch to get around anyway.
      • My uncle had a small blind dog, and it fairly quickly learned the position of all the furniture in his house and would run around like it was sighted. Course, my uncle wasn't quite right and would move things so he could watch the dog run into them at full speed...

    • Can't speak to this device since it looks a lot more complex, but I did a similar project in school for my EE. It ended up pretty simple after considering more complex options. The device had an ultrasonic emitter, an ultrasonic receiver, a 555 timer and a speaker. The 555 drove the emitter and speaker at a given frequency of chirps. However if the receiver got the pulse early it would interrupt the 555 and cause it to transmit sooner. Thus as an object got near the frequency of chirps would go up.


  • ... Except its batteries can run out when the person is in the middle of a busy highway.
    • by Anonymous Coward

      How would a cane help in the middle of a busy highway?

      • Re: (Score:2, Funny)

        by Anonymous Coward
        You can hide your cigars in it if the nurse doesn't let you smoke.
    • Yeah, I sure wish those blind people would stay off the highway. They're enough of a road hazard already!

      Oh, you mean crossing a street? I guess they'd just do it the old-fashioned way in that case.

  • by AthanasiusKircher ( 1333179 ) on Sunday August 21, 2011 @11:33PM (#37164730)
    From the summary (a suggestion that sounds improbable and unadvised): strapping a bat to your wrist to help you see...

    From TFA:

    This is a project I'm calling Tacit. No, I didn't bother making an awkward backronym for it....

    I think he's not telling us everything. I'll bet the T in TACIT stands for pteropine... it's just that the 'p' is tacit......

  • human echolocation (Score:4, Informative)

    by phantomfive ( 622387 ) on Monday August 22, 2011 @12:04AM (#37164826) Journal
    Blind humans can do a better job of echolocation just with there ears. Check it out [] (An amazing more complete version, but it's long []).

    There's even a school that helps teach echolocation to blind people [], based in California, I believe. Wikipedia has a basic writeup on it [].

    Seriously it's pretty amazing to think that a human can develop echolocation ability. But we can.
    • The augmented sensitivity of hearing doesn't immediately happen when you go blind, it's something that improves over time, as an individual's senses are forced to compensate. I can see this being very useful for somebody who just lost their sight, or a blind individual who doesn't feel like attending a class.

      It's another option on the table, and that's exactly what I believe it was intended to be.

      • Are you one of those people who, when they find something new, cannot resist the urge to say why it is wrong? 'Blind people who don't feel like attending a class?' What?
        • Are you one of those people who, when they find something new, cannot resist the urge to say why it is wrong? 'Blind people who don't feel like attending a class?' What?

          Troll. You dropped a textual deuce all over the device listed in the article, then when someone pointed out more than one use case in which the device listed in the article could be useful, suddenly the other person is the one who "cannot resist the urge to say why it is wrong". Piss off.

          • Oh yeah? How big exactly is the set of people who are blind, don't like to go to classes, and want to learn how to use a hand sonar? You may call me a troll, but you aren't thinking clearly.
            • All of the blind people who use public restrooms, perhaps? Have you ever tried to find the toilet paper in a public restroom when the bulb has failed, or when the light switch is difficult to find?

              • Have you ever tried to find the toilet paper in a public restroom when the bulb has failed, or when the light switch is difficult to find?

                No actually, have you? Because it doesn't sound that sounds like all you have to do is reach around touching the walls until you find it. I mean, I'm sure finding toilet paper is a thing that might be helpful for blind people, but are you sure this device would help very much with that task?

            • Oh, goodie, another idiotic troll to pick apart! Hey, Captain Asperger's, did it occur to you that maybe the guy to whom you were replying mis-used the term "don't feel like going to classes" for the more understandable "lack the time or money to be able to go to a class"? I'm curious, are you volunteering to pay all the legally-blind people in the world with day jobs and busy schedules to attend the class? If not, shut the fuck up, you pathetic trolling piece of shit.
              • And the winner is...

              • I would have to assume a very large percentage of blind people are on disability. Someone who has just turned blind almost certainly is on disability (Not many people have jobs that can be done blind these days, can you name 3 jobs that don't involve navigating thin hallways, operating a computer (obviously not your computer so it hasn't been specially adapted for the blind), handling money etc.... Secondly money and experience, I'm sure the basics of the hand sonar will not take long, but actually using it
    • For two separate, month long periods about a year apart, I spent 30-45 minutes a day practicing echolocation.

      Do NOT start practicing in a carpeted room/house.
      DO start in a room with relatively hard surfaces first.
      DO start with your hands cupping your ears. The hardest part of this will be getting the consistency of your hand cups, but you'll come to recognize the tone of the rushing blood in your ears for consistent positioning.

      I never got very good, but did get to a point where in a dark room, I can get a
      • Sweet! I love hearing this kind of story! I was wondering what it would take for a non-blind person to get the hang of this. How long did it take before you started to get anything?
  • I think they really should have included that old submarine sonar ping [].

    Also, having watched the video... that's not going to work very well in a crowded room - the blind guy could be hit with a lot of sexual harassment complaints. It might make more sense built into some sort of headgear.

    • It was originally mounted on headgear, but presented problems. Aside from looking goofy, a version based around the head misses most obstacles, since they are generally near the ground.
  • dual use (Score:5, Funny)

    by Black Parrot ( 19622 ) on Monday August 22, 2011 @01:13AM (#37165032)

    And when someone hassles you too much, you just set it on 'stun' and give them a blast with it.

  • by frosty_tsm ( 933163 ) on Monday August 22, 2011 @01:24AM (#37165056)
    But if it's only sound-based, it's doomed to fail.

    Back in college (which wasn't exactly eons ago) I was programming robots to maneuver spaces using 1) a camera and 2) sonar and 3) infrared. As cool as sonar was, it had two major drawbacks. First, it could only check distance about once a second (partly due to the fact that there were 12 of them, but you get the idea). Second, the sound was very prone to being absorbed (fabric on a cube wall) or dispersed (angles). This resulted in some amusing thumps as the bot would get a no-response from the cube wall, think that it was wide open, turn to it, and floor it.

    Add some EM sensors and then you'll have something that makes the life of a blind man easier.
  • Unless the blind are supposed to be using this device while submerged under water...
  • this is one component closer to my superhero costume.

  • OK, this has some extras but white canes with SONAR and feedback existed in the mid 70's if not earlier.
    • You display an astounding lack of perspective. This is a home-made gizmo that runs off a 9V battery and is only a little bulkier than a fingerless glove with a cellphone stuck to it. I think that's a legitimate advance, in much the same way that the automobile was a significant progression from the steam wagon.

  • Why a sonar?
    Why just "aptic feedback"?
    I would have also a few cameras with image recognition (a-la kinect) on a head belt and a synthesized voice to whisper indications to the bearer.
    There are materials that cannot be easily detected by sonars as there are objetct not easily recognized by image analysis.
    The real breakthrough would be the blind to ask the computer: "what's written on this funny slashdot comment"?
    Or, what making noise on my left?

  • The Tacit, a wrist mounted sonar device with haptic feedback, is like strapping a bat to your wrist to help you see.

    Uh... yeah. That's exactly what it's like.

  • It might be a good combo with this gizmo []. Wonder if any blind people have tried the compass out?
  • "I've got an eye on my hand"

"Pull the wool over your own eyes!" -- J.R. "Bob" Dobbs