Visually Impaired Pulse Echo Ranging (VIPER)

A technology for helping those whose vision is impaired to more easily navigate through their local environments

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Some people have diminished vision or no vision, which can impair spatial perception. Impaired spatial perception can impair awareness of surroundings, which can impair mobility and performance of tasks.

By sequentially generating precisely tailored acoustic pressure waves propagating in several directions, the pressure waves adapted to interact with environmental objects and to produce responses audible to a user, the user can rely on the external structures of the user's ears and the binaural inputs provided by the user's two ears to facilitate enhanced spatial perception of the locations of the environmental objects. Accordingly, those with vision impairments can more easily navigate based on their enhanced awareness of the locations of the environmental objects.

VIPER uses technology protected by United States Patents No. 8,059,823 and 8,391,499. No licenses or permissions of the patented technology have been granted. Discussion of such possibilities is welcome.

Part 1 of the VIPER video shows a blind user using the prototype to navigate in his home:

Part 2 of the VIPER video shows opening the enclosure to reveal the internal components of the prototype:

The prototype shown above uses an Atmel ATtiny13V 8-bit microcontroller to drive four n-channel MOSFETs, each of which pulses a piezoelectric transducer. The transducers used in the prototype are piezoelectric horn tweeters obtained from All Electronics. A 150-ohm resistor is connected across each tweeter. The prototype is powered by ten AA batteries, nominally providing 15 volts DC, which is switched by the mini toggle switch on the enclosure. The 15 volts DC is applied directly to the tweeters, with the MOSFETs between the tweeers and ground, energizing the tweeters when short positive pulses are applied to the gates of the MOSFETs by the microcontroller. The 15 volts DC is also applied to a 78L05 regulator to provide 5 volts DC to power the microcontroller.

The microcontroller sequentially pulses the transducers, for example, in a left, right, down, forward pattern. The directivity of the transducers provides respective sectors of coverage. The sectors of coverage need not be mutually exclusive but can provide a diversity of echolocation to the ears and brain from which a more complete and detailed spatial image may be formed.

After each sequence is performed, a pause is provided. Unlike other assistive technology that provides continuous stimulus to the user, the VIPER prototype is essentially time-division multiplexed with the ambient audio cues from the environment surrounding the user, allowing the user to receive all of those diverse cues undisturbed except during those few milliseconds during which the pulses and their echoes are heard. Thus, the VIPER prototype can provide new information to a user without appreciably disturbing the user's ability to receive information from existing sources.


Assembly language code for Atmel Studio

plain - 2.09 kB - 10/10/2016 at 14:25


Portable Network Graphics (PNG) - 17.59 kB - 10/09/2016 at 23:26


pro - 1.03 kB - 10/09/2016 at 19:28


gpi - 1.30 kB - 10/09/2016 at 19:28


pin - 1.43 kB - 10/09/2016 at 19:28


View all 19 files

  • 1 × Atmel ATtiny13V 8-bit microcontroller in 8-pin package
  • 4 × 2N7000 N-channel MOSFET
  • 4 × Piezoelectric tweeter Piezoelectric tweeter with exponential horn
  • 4 × Resistor Resistor across piezoelectric tweeter terminals
  • 1 × 78L05 5V fixed three-terminal voltage regulator

View all 11 components

  • Human tongue clicks and how the brain performs echolocation

    R. Snyder10/10/2016 at 00:41 0 comments

    At least one blind person has developed a high level of proficiency in echolocation using tongue clicks. However, the clicking tongue is a single emitter. The VIPER device provides multiple emitters oriented in different directions to allow a mosaic image to be formed from multiple sectors of echo information, enhancing overall spatial perception.

    Self-consciousness of making clicking sounds with one's tongue can discourage persons from making tongue clicks. The electronically generated acoustic pulses of the VIPER device can avoid such self-consciousness by attributing the sound to the device, not the user, similar to way those who are uncomfortable singing karaoke are generally comfortable listening to music from other sources.

    Functional magnetic resonance imaging (fMRI) provides an amazing way to study the portions of the brain involved in various human activities in real time. Scientists have used fMRI to study human echolocation in early and late blind echolocation experts.

  • Uploaded video of the VIPER prototype

    R. Snyder10/10/2016 at 00:05 0 comments

    Parts 1 and 2 of a video of the VIPER prototype have been uploaded to Vimeo. See details section above for links.

  • Uploaded photo of waveform on digital storage oscilloscope (DSO)

    R. Snyder10/09/2016 at 23:20 0 comments

    My Tek 2212 DSO isn't the latest technology, as can be seen from the sparse dots of the waveform, but, with a microphone connected to it, it does reveal that the pulses rapidly rise and exponentially decay, falling to half their peak level within 3mS. Sound travels at approximately 340m/s, but, since it has to go out and come back before the echo is received, its speed is effectively halved to approximately 170m/s for echolocation in terms of distance to the object being perceived. That means the approximately 3mS pulse effectively occupies about half a meter of echolocation range.

    The pulse waveform oscillates at around 2.3kHz, perhaps as a result of a resonant frequency of the piezoelectric transducer. I have ordered more transducers and plan to employ them in different ways and possibly modify them to alter any resonances they may have.

  • Uploaded prototype photos

    R. Snyder10/09/2016 at 21:29 0 comments

    Posted high-resolution photos of the project showing the VIPER prototype inside and out.

  • Uploaded netlist, pinlist, and other files

    R. Snyder10/09/2016 at 19:30 0 comments

    The uploaded files have the file extensions .net, .pin, .gpi, and .pro.

  • Uploaded NC drill files

    R. Snyder10/09/2016 at 19:25 0 comments

    The NC drill files, with the file extensions .drd, .dri, and .whl, are Excellon NC drill files.

  • Uploaded Gerber files

    R. Snyder10/09/2016 at 19:18 0 comments

    Note: The Gerber files, with file extensions .cmp, .sol, .plc, .pls, .stc, and .sts, are Gerber RS274X files.

  • Uploaded PCB layout

    R. Snyder10/09/2016 at 19:12 0 comments

    Note: The piezoelectric transducer pads, power switch pads, and battery pads are laid out as if those components are to be mounted on the printed circuit board (PCB), but those components can (and at least in the case of the transducers should) be separated from the PCB by wires.

  • Uploaded schematic diagram

    R. Snyder10/09/2016 at 19:08 0 comments

    Note: The schematic diagram shows TN0604N3 MOSFETs as they were available in the parts library and have the same pinout as the 2N7000 specified in the bill of materials. The schematic diagram also shows piezoelectric transducers that were available in the parts library, but any of a wide range of piezoelectric transducers can be used. The capacitor and resistor values are not critical, and a wide range of values can be substituted.

  • It's not just engineering. It's science.

    R. Snyder10/08/2016 at 00:48 0 comments

    The carefully tailored acoustic pulses emitted by the VIPER provide an abrupt wavefront that reduces ambiguity in spatial perception even if simply providing a higher signal-to-noise ratio of the returning wavefront. However, those pulses are also interesting in that there is a phenomenon known as the precedence effect, which describes a psychoacoustic masking of subsequent wavefronts after a first wavefront is perceived. The duration over which the masking persists is dependent upon the nature of the sound being heard, with a shorter duration of masking for acoustic pulses and longer duration for more complex sounds. Accordingly, the carefully tailored acoustic pulses of the VIPER provide advantage not only in perceiving the range of the closest acoustically reflective object, but also in resolving additional objects at greater distances.

    Recent research suggests that a person's engagement in an echolocation task, as opposed to mere listening, can reduce psychoacoustic echo suppression. As the experiment distinguished between listening to exogenous sounds and engaging in echolocation using self-vocalized sounds, it appears some question may remain as to how echo suppression may be affected when engaging in echolocation using exogenous sounds. While control experiments were performed to attempt to distinguish effects of self-vocalized sounds vs. exogenous sounds, it is questionable whether the duration of such experiments were commensurate with the on-going duration of interaction of a user with the VIPER.

    One question I have is whether a user's extended interaction with the VIPER can inhibit echo-suppression during the echolocation task even with exogenous sounds. One phenomenon that could conceivably support such improved performance over time is neuroplasticity.

    Even if the precedence effect were not appreciably reduced, that is not problematic for the VIPER, as precedence effect still allows perception of the echo from the closest acoustically reflective object, which being nearest to the person using the VIPER, is likely a more important object of which to be aware than objects farther from the person.

View all 14 project logs

  • 1
    Step 1

    Before continuing, obtain a personal non-commercial non-transferable non-exclusive limited license to the patented technology (contact me for details).

  • 2
    Step 2

    Build a circuit board having the voltage regulator, capacitors, microcontroller, and MOSFETs. The resistors may be included on the circuit board or installed across the piezoelectric tweeter terminals.

  • 3
    Step 3

    Cut holes in the enclosure to mount the piezoelectric tweeters and the power switch.

View all 13 instructions

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