SU1053829A1 - Ultrasonic locator for the blind - Google Patents

Abstract

1. ULTRASONIC LOCATOR FOR RELAYS, containing serially connected electroacoustic transducer, receiver, multivibrator, transmitter and indicator device; connected to the output of the multivibrator, T and its supply by the fact that, in order to improve the accuracy of determining the distance to the obstacle by separating the near and far zones, it is equipped with a scale measurement unit of time intervals connected between the receiver and the multivibrator, and the indicator device is made in the form of a buzzer and two tactile sensors connected via a logic circuit to the output of a multivibrator. 2. Locator in accordance with Clause 1, of tl and h a, y, and, with the fact that the scale measurement unit of time intervals is made of a series-connected trigger, an RC circuit, a threshold circuit with a pulse shaper, (L With this, the trigger input is connected to the output of the receiver, and the output of the threshold circuit is connected with the input of the multivibrator. In:

Description

The invention relates to medical technology, namely, devices for orientation of the blind in the current world.

Known ultrasound locator for the blind, consisting of a transmitter of ultrasonic pulses, a receiving logic indicator device G.

However, a well-known ultrasonic device has a significant error in determining the distance to an object located within 1-2 m from a blind person.

The closest to the present invention is an ultrasound locator for the blind, containing a series-connected electroacoustic transducer, receiver, multivibrator, transmitter and indicator device connected to the output of the L2 multivibrator,

However, in the known ultrasound locator for the blind, the pulse repetition frequency of the transmitter weakly depends on the range, which leads to large errors in determining the short distance to obstacles.

The purpose of the invention is to improve the accuracy of determining the distance to an obstacle by isolating the near and far zones.

The goal is achieved by the fact that an ultrasonic locator for a network containing serially connected transducers, a receiver, a multivibrator, a transmitter and an indicator device connected to the output of the multivibrator is equipped with a scale measurement unit of time intervals connected between the receiver and the multivibrator, and the indicator device is in the form of a sound signal, a lysator, and two tactile sensors connected through a logic circuit to the output of a multivibrator.

In this case, the scale measurement unit of the time interval can be more of the consequently connected trigger of the QC circuit, the threshold circuit with the pulse shaper, the trigger input connected to the receiver output and the threshold circuit output with the multivibrator input.

FIG. 1 shows a functional for an ultrasound locator for the blind; in fig. 2 is a block diagram of the indicator device; Fig. 3 are time diagrams for explaining the operation of the ultrasound locator for the blind; Fig. 4 is a diagram of a scale measurement block; Fig. 5 shows timing charts explaining the operation of a scale measuring unit of time intervals;

The ultrasound locator for the blind contains an electroacoustic transducer 1, a receiver 2, a scale measurement unit of time intervals 3, a multivibrator 4, a transmitter 5, and an indicator device b. The indicator device consists of two tactile sensors 7 and 8, a sound sensor 9 and a logic circuit consisting of a comparison circuit 10, trigger 17, switch 12, zone 13 multivibrator, tone generator 14, time scale measuring unit consists of trigger 15, KS- a circuit including resistors 16 and 17, a diode 18 and a capacitor 19, a threshold circuit consisting of an AND-NE element 20, a diode 21, a resistor 22, with an output pulse driver comprising a differentiating chain of a capacitor 23 and a resistor 24 and an amplifier circuit on tr anzistor 25,

The ultrasound locator for blind works in the following way,

In the absence of obstacles, the multivibrator 4 is in a self-oscillating mode with a repetition frequency of about 1.5 Hz and produces short impulses that trigger the transmitter 5. In the presence of obstacles, ultrasonic pulses reflected from either the electroacoustic converter 1 are electrically transformed and amplified by receiver 2 to block 3 of the scale measurement of time intervals. In block 3, the time distance between the probe pulse of the transmitter 5 and the reflected pulse at the output of the receiver-2 is converted to the scale factor K, the Impulse from the output of block 3 starts the multivibrator 4, which in the presence of reflected signals already works as a waiting one, since the period of its natural oscillations is more than -2 T) dy. The impulse of the multivibrator 4 starts the transmitter 5 and the cycle repeats. Thus, the locator works as a pulse generator, the frequency of which depends on the distance. The frequency of the multivibrator 4, as well as the transmitter 5, carries information about the distance to the nearest obstacle and is expressed as

mule

i

2TK

Expressing time through the range D and the propagation speed of the ultra / sound 1, we finally get

iJ-l.

2DK

The operation of the scale measurement unit 3 of time intervals is explained by voltage plots (FIG. 5). Pulses from multivibrator 4, which start up transmitter 5, enclosed a yuttrigrep 15. Condenser 19 begins to discharge in a circuit — open diode 18, resistance 16. First reflected the impulse coming from receiver 2 switches trigger 1 and capacitor 19 starts charging across the string 16,, 17,19. Other pulses from the output of receiver 2 in this period of sounding cannot change the state of trigger 15. The reflected pulses that fall into the next period of sounding lie below the response threshold of receiver 2, since K is chosen so that the inequality T is satisfied (jK, where TO is the minimum time interval measured by the locator determined by the transmitter 5 pulse duration. Except In addition, the temporal gain control system of receiver 2 additionally suppresses these pulses. Thus, the ultrasound locator provides operation only on the first reflected pulse.

When the voltage of the circuit 20 is reached on the capacitor, a positive impulse is formed at the output of unit 3.

The chain 21, 22 serves to keep the charged capacitor 1 voltage close to the threshold voltage.

The distance measured by the locator is divided into two zones: closest to 1 mm, i.e. warning of direct contact with the obstacle, and all the rest. Two blind fingers are constantly located on tactile sensors 7 and 8, each zone has its own sensor, and a sound sensor 9 during the transition

one zone to another changes the tone of the emitted pulses.

The indicator device 6 operates as follows.

Pulses from multivibrator 4 through 5 are given to zone multivibrator 13, producing a pulse with a duration corresponding to a distance of 1 m, which is fed to comparison circuit 10, and a pulse from receiver 2 also arrives. The voltage from the output of comparison circuit 10 controls and the latter controls switch 12. Switch 12 connects a pulse signal from g / ltivibrato 5 pa 4 to either one or the other i-tactile sensors 7 and 8 depending on the distance. Trigger 11 also controls depending on the distance tonal frequency th oscillator 14,

Q which is modulated by pulses with

multivibrator 4. The two-frequency pulses from the output of the tone generator, torus 14 are fed to the sound sensor 9.

5 Thus, the introduction of a scale measurement unit of time intervals excludes in the ultrasonic locator a constant delay equal to Eremen of the passage of the ultrasonic pulse from the locator to the obstacle located at the maximum distance; and the distance to closely spaced objects is determined great accuracy.

5 / The invention provides an increase in the accuracy of determining the distance to the object by introducing two | 3on in range, in addition, by introducing current modulation, the sensory sensitivity is increased.

fug. /

FU1. yy

fug.

Claims (2)

1. ULTRASONIC LOCATOR FOR THE BLIND, containing serially connected electro-acoustic transducer, receiver, multivibrator, transmitter and indicator device j connected to the output of the multivibrator, with the exception of * that ', in order to improve the accuracy of determining the distance to the obstacle by highlighting the near and far zones, it is equipped with a scale measurement unit for the time intervals included between the receiver and the multivibrator, and the indicator device is made in the form of an audio signaling device and two clock cycles ial sensors connected via a logic circuit with the output of the multivibrator. 2. The locator according to claim 1, with the fact that the scale measurement unit of the time intervals is made up of series-connected trigger, RC circuit, threshold § circuit with a pulse shaper, while the trigger input is connected to the output of the receiver, and the output of the threshold circuit is connected to the input of the multivibrator. FIG. 7 I .1.053829