An Introduction to Echolocation with Sunu band

What is Echolocation?

Certain animals like bats and dolphins are able to navigate their environments using sound. Echolocation is the ability to use sound and echoes that reflect off of matter in order to find the exact location of objects within an environment.  

Bats are capable of producing high frequency sounds. These high frequency sound waves, known as ultrasound, interact with objects that are within the environment, and a portion of these ultrasonic waves ‘bounce back’. These reflected sound waves are called echoes. Bats listen for these echoes to know their position in space and their relative distance to objects that are within their environment.

Humans are also capable of using echolocation. Daniel Kish, President of World Access For The Blind is the pioneer of human echolocation, he has been training blind travelers to use the human echolocation technique for years. Human echolocators navigate their surroundings by producing a series of ‘clicks’. Human echolocators are trained to listen to the echoes their sound waves produce and through these soundwaves are able to gage the location of objects within their environment. Thanks to the miniaturization of sensors and precision actuators, Sunu Band is capable of realizing the electronic form of echolocation.

How Sunu Band Uses Sonar for Echolocation

Sunu Band enables you to navigate your surroundings with echolocation by combining sonar with precise vibratory feedback that you can feel on your wrist. Sunu Band uses a sonar transducer that is capable of emitting high frequency sound waves while ‘listening’ to- or detecting the reflected sounds or echoes that bounce back off objects.

Haptic Feedback

The Sunu Band processes the information derived from the reflected sound or echoes and relays that back to the user via a series of precise vibratory pulses. This is referred to as haptic feedback — the use of tangible feedback to transform and relay information to the user.

Sonar is Directional

Sunu Band is only capable of detecting the echoes (that reflect off of objects) from the same direction in which the ultrasound is emitted. In other words, think of Sunu Band as a flashlight that uses sound instead of light. Just like any flashlight, the direction in which you aim the sonar sensor is where you will be able to detect the presence of objects.

The ultrasonic wave emitted from the sonar sensor travels away from the Sunu Band in the form of cone. Objects that are within the area of this cone will interact with the ultrasound and produce echoes.

Should you wear Sunu Band in a particular way?

You can wear Sunu Band on either your left or right hand. It is important to wear Sunu Band so that the sonar sensor is on the same side as your thumb. The reason for this is when you bring your arms to your side, as you get ready to walk, the natural position of your hands and wrist will allow the sonar sensor to point directly ahead.

Sonar Range

The maximum distance at which we begin detecting the presence of an object that is in the same direction of the sonar sensor is referred to as the sonar range. Sunu Band uses two distinct sonar modes:

  • Short range mode: detects objects up to 4-5 ft. or 1.5 meters away. You swipe-in on the touchpad to enter into the short range mode. You will immediately feel one pulse to indicate that you are now in the short range mode.
  • Long range mode: detects objects up to 15 ft. or 5 meters away. You swipe-out on the touchpad to enter into the long range mode. You will immediately feel two pulses to indicate that you are now in the long range mode.

How the vibration feedback changes when you approach an object.

Sunu Band uses vibrations to tell you that an object is nearby. The frequency of the vibration pulses changes as you get closer (or further away) from the object. Sunu Band changes the frequency of the vibration pulses to provide you with a sense of how close an object is. Here is what happens to the vibration pulses when an object is within range:

  • Intermittent pulses: mean that Sunu Band is detecting an object that is at the limit of the range of the current sonar mode. These intermittent pulses tell you that there is an object furtheR away from you.
  • Moderate pulsations: mean that Sunu band is detecting an object that is closer to you in range. As you approach the object, the pulses become more frequent. As you become further away from the object, the pulses become less frequent.
  • Constant vibration: means that an object is sufficiently close to you that you should either stop or pay close attention, you may soon collide with said object. As soon as you feel constant vibrations, you may extend your hand (or cane) and touch the object.

Sonar Sensitivity

Sunu Band’s sonar modes are designed to enable you to navigate outdoor and indoor environments, or spaces that are more open (with less obstacles) and spaces that are more crowded. You can switch between the two sonar modes to navigate these kinds of environments.

Each sonar mode has a specific range and sensitivity. Sensitivity is the power at which the ultrasound is emitted from the sonar sensor. In other words, the sensitivity is like the volume on your stereo. Varying the sensitivity of the sonar sensor allows us to navigate various environments such as crowded space or more open spaces like the outdoors. Generally speaking, with:

  • High sensitivity: we are able to detect thinner objects like signposts, tree branches, bushes, etc. High sensitivity is useful when navigating outdoors like on sidewalks, or in parks, etc.
  • Low sensitivity: we are able to detect gaps such as spaces between people, doorways and thresholds. Low sensitivity is ideal in indoor spaces or in situations where you want to find a gap or doorway. It is also useful for trailing or queuing in a line, for example when you are traveling, waiting in line at the bank or even getting in line to order your morning coffee.

Sunu Band’s sonar mode default settings are as follows:

  1. Short range mode: low sensitivity
  2. Long range mode: high sensitivity

Ultimately, the sonar mode you use is entirely up to you. The Sunu App allows you to customize your sonar modes to fit specific needs. Within the Sunu App you can adjust the sonar range and sensitivity. Remember that you can revert back to the device default settings at anytime.

Introductory Exercises

The following exercises are intended to help you become acquainted with Sunu Band’s sonar and haptic vibratory feedback. You can carry out these exercises standing in place.

Exercise 1. Sensing The Presence or Absence of a Nearby Object

Now that we’ve learned how the Sunu Band’s sonar and vibratory feedback work, let’s begin by experiencing what it feels like when an object is close to you and when it’s further away. To begin this exercise:

  1. Wear the Sunu Band on either hand. For this example, as well as all of our exercises we’ll use our right hand.
  2. Press the navigate button. You will feel a long pulse followed by one short pulse.
  3. Switch to the short range sonar mode by swiping-in on the touchpad. You will feel one short pulse to indicate that you are now in the short range sonar mode.

Now that Sunu Band is ready and we are standing in place, we will do the following:

  1. Stand in a place that is clear of objects, any object should be at least 4-5 ft. or 1.5 meters away.
  2. Lower you hand wearing the Sunu Band (right hand) so that the inside of your palm is touching the front of your thigh. This will align the position of the Sunu Band and the sonar sensor for the following exercise.

You should not feel any vibratory feedback at this time because there are no objects that are within range and in the direction of the sonar sensor.

Now let’s feel what happens when an object is close by:

  1. Slowly raise your other arm, the one without Sunu Band (the left arm), and observe what happens to the vibratory feedback.
  2. As you raise your other arm, there will be a point where your arm and hand are directly in the path of the sonar sensor. Notice how the vibration feedback feels.
  3. You will feel constant vibrations when your arm is directly in front of the sonar sensor. The constant vibrations mean that your arms is sufficiently close to the sonar sensor.

Now let’s do the reverse by:

  1. As you lower your other arm you’ll notice what happens to the vibratory feedback as soon as your arm is no long in the path of the sonar sensor.

Repeat this exercise a couple of times until you feel comfortable sensing your free arm with Sunu Band.

Exercise 2. Sensing the Direction of An Object

Now we’re going to explore the importance of aiming the sonar sensor and how we can discern if an object is to our left, right or directly in front of us. We can do this exercise by standing in place. To begin this exercise:

  1. Wear the Sunu Band on either hand. For this example, as well as all of our exercises we’ll use our right hand.
  2. Press the Navigate button. You will feel a long pulse followed by one short pulse.
  3. Switch to the short range sonar mode by swiping-in on the touchpad. You will feel one short pulse to indicate that you are now in the short range mode.
  4. Stand in a place that is clear of objects, make sure the closest object is at least 4-5 ft. or 1.5 meters away.
  5. Lower the hand wearing Sunu Band (right hand) so that the inside of your palm is touching the front of your thigh. This will align the position of the Sunu Band and the sonar sensor for the following exercise (the position is the same as in the first exercise).

You should not feel any vibratory feedback at this time as there are no objects within range and in the direction of the sonar sensor.

  1. Now raise your other arm slowly at a low altitude until you feel constant vibration feedback from the Sunu Band. At this point, your arm is directly in the path of the sonar sensor.

Now let’s change the direction in which we are aiming the sonar sensor and observe what happens:

  1. Slowly begin rotating the wrist that is wearing the Sunu Band (the right-hand). Try to only rotate the wrist without lifting your arm.
  2. As you rotate your wrist notice what happens to the vibration feedback.
  3. Keep rotating your wrist until your palm is facing forward.

You aim the sonar sensor by rotating your wrist which in turn changes the direction the sonar cone is aiming. The vibrations stop as soon as the object is no longer in the direction of the sonar sensor.

Now let’s repeat the exercise inversely:.

  1. Rotate your wrist (that is wearing Sunu Band) in the opposite direction until you feel the vibration feedback.
  2. Your palm should now be facing or touching your front thigh.

Practice this exercise a couple of times, until you feel comfortable with sensing your arm by rotating the wrist with the Sunu Band.

Exercise 3. Sensing your proximity to an object.

Being able to sense your proximity to an object is important when avoiding obstacles and navigating within your environment.  In this exercise, we’re going to learn how the vibratory feedback changes as we get closer (or further away) from an object. We are also going to take our first steps with Sunu Band.

Let’s use a familiar wall as our beta object. Choose an environment that you know and are comfortable in for you to do this exercise. Ideally, you want to have enough room to walk towards, and away from the wall–approximately 6 ft. or 2 meters. Make sure that there are no obstacles between you and the wall.

To begin this exercise:

  1. Wear the Sunu Band on either hand. For this example, as well as all of our exercises we’ll use our right hand.
  2. Press the Navigate button. You will feel a long pulse followed by one short pulse.
  3. Switch to the short range sonar mode by swiping-in on the touchpad. You will feel one short pulse to indicate that you are now in the short range mode.

Let’s begin the exercise by facing a wall about 1 ft. or a half-meter away.

  1. Bring your arm (that’s wearing the Sunu Band) to your side, your palm should be facing flat against the side of your hip or thigh. We want to make sure that the sonar sensor is aiming directly ahead or towards the wall.
  2. Notice the vibratory feedback that you are feeling on your wrist. You should feel constant vibratory feedback. That’s because you are very close to the beta object, in this case, the wall.
  3. Now, maintaining your hand and wrist in the same position–aiming the sonar sensor toward the wall, slowly take a few steps back.
  4. Notice what happens to the vibration feedback that you feel on your wrist.
  5. Now continue taking a few (2-3) steps back. Notice how the vibratory feedback changes.
  6. Keep taking a few steps back until you no longer feel vibrations or pulses on your wrist.

This exercise allows you to feel how the haptic vibration changes as a function of your proximity to the wall. When we started the exercise, the vibration feedback was constant, because you were standing very close to the wall. Similar to our first exercise, you feel constant vibrations when you are very close to an object, close enough that you may even touch it or tap it with your cane.

Now as we walk away from the way, the vibratory pattern changes. We begin feeling pulses on our wrist. The pulse may be quite frequent, and this indicates that the object is near or within range.

Finally, as you continue walking away from the wall, you feel the vibration pulses become less frequent or intermittent. This means that the wall is at the maximum distance that the sonar can detect. As you continue walking away, the vibration pulses will stop.

Walking Toward the Wall:

Now let’s try repeating the exercise while walking toward the wall:

  1. Begin at a distance where you do not feel any vibrational pulses.
  2. Make sure that your arm is at your side and that the sonar sensor is aiming forward. Your palm should be facing flat against the side of your hip or thigh.
  3. Take 2 steps towards the wall and observe for any changes in the vibration feedback.
  4. Continue taking 2 steps toward the wall paying particular attention to when you begin feeling vibration pulses on your wrist.
  5. Continue taking a few steps towards the wall.
  6. Stop as soon as the vibrations become constant.

At this point, you are very close to the wall. To verify, carefully extend your hand until you can touch the wall.

Continue practicing this exercise until you are comfortable using the vibration feedback to knowing when you are getting close or further away from the wall.

What’s Next

We’re soon adding new content that are prepared by experts in orientation and mobility that will help you learn how to incorporate Sunu band in your daily routine. Feel free to check out the videos below. Remember to review our important safety information. Practice in a known and safe environment. Please feel free to reach out to us at hello<at>sunu<dot>io if you have any questions.

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