EchoVision: A Navigation Device for the Blind
One solution to alleviate the struggles of the blind is to create a navigation device, known as EchoVision, based on active sonar technology and the echolocation abilities of bats. It would resemble an open-ear or open-fit hearing aid in appearance.
This device would serve the purpose of assisting the blind navigate on a daily basis without the use of the cane that many blind people currently use. EchoVision would constantly emit sounds, too high in frequency for the human ear to hear. Therefore, it would not be a disturbance to other people in close proximity. These sounds would reflect off objects and the reflections of these pulses of sound would give information on the distance from the device of the object that gave the reflection or echo.Also, information about the size of the object and its direction of motion could be retrieved using this device. The method that EchoVision would use is a technique similar to a type of active sonar system, called monostatic sonar.
As in a monostatic sonar operation, the sound transmitter and receiver are both in the same place, and in this case, that place would be in the device. When in use, the sound transmitter on this device would create pulses of sound. The sound receiver, a microphone, would then receive the reflections of the sound pulses previously emitted. From the sounds picked up by the receiver, the distance away from the device, as well as the size and direction of movement of the object could be determined. The distance could be found by determining the speed of sound in the area and the amount of time it took for the reflection of the pulse to be received.
The formula to find the distance to the object would be the time from the beginning of the pulse to the beginning of the echo, multiplied by the rate at which sound is moving in that area, divided by two. This formula works because distance is found by multiplying the rate and time, and to find half of this, only the distance from the person to the object, instead of there and back, the quantity is divided by two. These calculations would be performed by the device whenever it emitted a pulse and received an echo. The size of the object could be determined based on the intensity of the echo. Larger objects would produce more intense echoes, by reflecting more of the sound wave, while smaller objects would produce less intense echoes by reflecting less of the sound wave. Additionally, the direction that the object is moving in, or its stationary state, would be found by determining the pitch of the sound.
Objects with a higher pitch are moving towards the blind person wearing the device, while objects with a lower pitch are moving away from the user. This is due to the Doppler effect or shift, a method that is used in astronomy to determine whether a star is moving towards or away from the earth. The difference is that this method uses light waves. If it is a red shift, it has a lower frequency, a lower pitch, and is moving away. If it is a blue shift, with a high frequency and pitch, it is moving towards.
Therefore, direction, away from or towards, is determined by pitch and the Doppler shift. For all of this information to be effectively gathered, the EchoVision device would need to contain multiple computer chips, or integrated circuits. An integrated circuit is a set of electronic circuits on one small plate, or chip, of a semiconductor material, typically silicon. Computer chips, according to wiseGEEK, “contain the circuitry that runs most modern computerized devices.” EchoVision is a computerized device, thus it must contain integrated circuits. There are many varieties of integrated circuits.
This device contains a microcomputer, and therefore, would have multiple microprocessor chips, or CPUs. The CPU is the central part of running a device. It retrieves instructions, based on the three systems explained above, from the program memory. It then translates the instructions into assembly language. The third step is for the CPU to execute the instructions. For example, it could now determine the distance of from the user to the object with the given formula.
To do this it would use the Arithmetic Logic Unit, also located in the device. Finally, the last step is to write the output or result of the previous computation in the memory. The CPU also includes a component known as the clock. The clock speed is the number of times the clock cycles per second, which is also equivalent to the number of instructions executed per second by the CPU; a typical clock speed is 2.8 billion cycles per second. The device would have a voice system built into it that would relay this information to the wearer of the device.
It would tell the blind person how far the surrounding objects are located, therefore preventing the user from colliding with a possible object. It would also provide the surrounding objects’ direction of motion and size. If an object is too close to the blind user to fully relay the directions without the possibility of colliding with the object, the device would emit a distinct series of beeps, audible only to the user. These series of beeps could be adjusted based on direction, size, and distance. For extremely close objects, the device would produce different combination of sounds, instantly recognizable to the blind person, which allows them to react right away, and prevent collision.