WO1996025135A1

WO1996025135A1 - Cane for the blind

Info

Publication number: WO1996025135A1
Application number: PCT/DE1996/000195
Authority: WO
Inventors: Horst Meiners; Johannes Lubetzki
Original assignee: Horst Meiners; Johannes Lubetzki
Priority date: 1995-02-17
Filing date: 1996-02-03
Publication date: 1996-08-22
Also published as: EP0809480A1; DE19680083D2; AU4618796A; DE19505402A1

Abstract

The invention concerns a cane for the blind which is equipped with a transmitter and a receiver. The difference between transmitted and received signals is associated by a computer with an acoustic signal which the blind person can hear and from which he/she can deduce special information about the space surrounding the cane. A cane of this type broadens the area of use of canes for the blind and provides blind people with comprehensive information about the structures in the space surrounding the cane.

Description

Cane

The invention relates to a cane for the blind.

The usual embodiment of a cane is known and widespread. A rod, usually painted white, made of the lightest possible material, such as aluminum with a handle and a tip, makes it easier for blind people to find their way around, by using the stick as an extended arm for scanning uneven ground. The blind man leads the stick in front of him in an arched swivel movement with the tip just above the floor and is thus made aware of an unevenness or edge by the mechanical contact of the stick with a surface.

This process is very simple. The possibilities of using a cane to measure structures in the room are limited to the line on which the cane is guided.

The invention is therefore based on the object of using the stick to obtain information about structures in space beyond the mechanically accessible area.

This object is achieved with a cane that has at least one transmitter that emits signals, at least one receiver of the signals receives, at least one computer which compares the transmitted signals with the received signals and assigns the difference at least one comparison signal and at least one loudspeaker which emits this comparison signal as an acoustic signal.

The combination of transmitter, receiver, computer and loudspeaker enables a comparison signal to be calculated from differences between emitted and received signals, which is emitted as an acoustic signal in order to provide the blind with information about the space surrounding the staff. All individual parts are so small that they can be easily accommodated within the stick or its handle. The loudspeaker can also be integrated directly into the stick or as earphones or headphones located directly on the blind man's ear. By emitting a wide variety of signals and comparing different qualities of the transmitted and the received signals, different information about the surroundings of the stick can be determined and communicated to the blind person by means of different acoustic signals.

The advantage of the invention thus lies in the fact that with the blind stick according to the invention a large amount of information from the surroundings of the stick can be acquired, which information is communicated to the blind person in the form of acoustic signals. The field of application of the known cane for blind people is therefore greatly expanded by mechanically scanning certain structures in space without having to do without the original function of the classic cane for blind people. E.g. The emitted and the received signals can be ultrasound signals and the computer can compare the intensity and / or quality of the emitted signals with the intensity and / or quality of the received signals and assign a first comparison signal to the intensity and / or quality difference. The intensity and quality of reflected ultrasound signals allow conclusions to be drawn about the material of the wall reflecting the signal. Thus, when mechanically scanning a structure, the blind person not only receives information about the spatial dimensions but also an indication of the type of material. In this way, for example, metal and, for example, concrete or asphalt surfaces can be easily distinguished and frequently occurring materials such as wood or earth can be assigned special comparison signals that the blind person can easily learn.

The loudspeaker can advantageously emit the first comparison signal, which indicates the intensity or quality difference between the emitted and received ultrasound signal, as a signal with a corresponding pitch and / or timbre. The timbre is particularly well suited to convey information about a special material to the blind.

The distance between a spatial structure and the stick can also be communicated to the blind person before the blind person hits the structure with the tip of the stick. For this purpose, ultrasound signals are also transmitted and received, and the computer compares the times of the transmitted signals with the times of the received signals and assigns a second comparison signal to the time difference. Since the time difference between the transmitted and received signal is proportional to the distance, the second gives Comparison signal to the blind an information about how far the determined structure is away from the transmitter. The blind person is used to striking structures first with the tip of the stick and it is therefore appropriate to place the transmitter and the receiver for the ultrasound signal in the area of the tip of the stick in order to inform the blind of the distance between the detected structure and the tip of the stick.

The closer the blind man with the stick comes to a certain structure, the more interesting is the information about its structure. It is therefore appropriate for the second comparison signal, which correlates with the distance, to be emitted as an acoustic signal with a corresponding volume.

Instead of ultrasound signals or in addition to ultrasound signals, infrared signals can also be emitted and received by the cane. In this case, the computer compares the intensity and / or the time of the transmitted infrared signals with the intensity and / or the time of the received infrared signals and assigns a third comparison signal to the intensity or time difference. This third comparison signal can, for example, indicate an unevenness in the floor by directing the emitted signal obliquely at the floor surface in front of the blind person and assigning the comparison signal which arises in the case of a horizontal floor surface to a zero line. If the course of the floor surface changes, for example in the form of a slope, the received portion of the transmitted infrared signal changes at the same time, and from this difference between the transmitted and received infrared signal, a third comparison signal can be determined which informs the blind person about the slope on the ground. The same applies to a slope or a step on the floor surface, which also changes the intensity of the reflected infrared signal. It is pleasant for the blind if a low signal is assigned to a floor surface facing downwards, such as a descending step, and a higher signal to an unevenness facing upwards, since the blind can easily learn a correlation between pitch and floor height .

It is also advantageous if the measurement of the difference between the emitted and received infrared signals is combined with a counter which assigns a fourth comparison signal to each projection when the blind cane (1) passes by projections. This is particularly suitable for counting levels that the blind person can perceive by sweeping the beam of the infrared signal over the suspected levels and counting the signals emitted by the counter.

The combination of third and fourth comparison signal makes it possible to encode up-going stages with a higher signal and to assign a lower signal to lower stages.

The blind person, who is informed about objects and their materials that are further away using the ultrasound signal, can use the infrared signal to examine structures closer to him. If he encounters an obstacle with the tip of the cane that has already been announced to him by the ultrasound signal, the increasingly louder second comparison signal, which indicates the distance to the identified structure, is interrupted in order to examine the structure more precisely with the infrared measurement. Even the first infrared signal shows through its pitch whether it is a structure that rises or falls in the broadest sense, ie, for example up or down stairs. In the further course of the measurement, the counter switches on, which, when the structure lying on the path of the blind man sweeps with the beam from the infrared transmitter, assigns individual abrupt structure changes, such as an individual stair step, to a special acoustic signal, the pitch of which either rises or increases falls off. This enables the blind person to determine not only the presence of a staircase, but also the number of steps and the direction in which the staircase runs.

It is also known that all telephones emit a special inductive scatter pulse. It is therefore useful to equip the cane with another receiver that is capable of receiving such a scatter pulse from any telephone and assigns a fifth signal to the received pulse strength, which the loudspeaker emits as a special acoustic signal. The blind man can thus also receive scattering impulses emitted by telephones with his cane and is thus informed of the presence of a telephone in the vicinity of the blind man. E.g. This dial tone pulse can be received from any telephone with a 10 kHz coil. The intensity of the received signal can correlate with the volume of the signal perceived by the blind person and the blind person therefore hears the dial tone of a telephone in the vicinity via his cane.

The electronic equipment of the blind cane opens up many other possibilities for providing the blind with additional information. E.g. A clock with a time announcement can be provided or the blind cane can have a small receiver so that the blind person can be called from any telephone. Such receivers can be dialed from a telephone State of the art and so small that they can be easily integrated into the cane.

All acoustic signals discussed here can be modulated in tone color, pitch and volume as desired; however, the individual items of information can also be communicated to the blind as voice signals.

An embodiment of the invention is described below with reference to the drawings.

It shows:

Fig. 1 shows a section of a blind staff according to the invention

Fig. 2 is a circuit diagram of an ultrasonic transmitter

3 shows a circuit diagram of an ultrasound receiver

Fig. 4 is a circuit diagram of an infrared transmitter and

Fig. 5 is a circuit diagram of a stage counter. The cane 1 consists of a housing 2, which consists of a handle part 3, a rod 4 and a ball 5. On the handle part 3, the rod 4 is fixed so that the rod 4 serves as an extension of the handle part 3 and at the front end of the rod 4, the ball 5 is provided as a conclusion.

In the ball 5 there is a transmitter 6 for the ultrasound signals and in the rod 4 there is a receiver 7 for the ultrasound signals. In between is a receiver 8 for signals from telephone systems. A step counter 9 is accommodated in the rod 4 above the receiver 7 for the ultrasonic signals. The generation and conversion of the ultrasound signals is carried out in the ultrasound unit 10, which binds above the stage counting unit 9 in the rod 4.

A volume control 11, the power supply 12 and an infrared device 13 are provided in the handle part adjoining the rod. In addition, there is an amplifier 14 in the handle part 3 for the received signals, a loudspeaker 15 connected to it and a socket 16 for the plug of a headphone.

The special arrangement of the individual elements within the cane 1 ensures that the ultrasound signals are transmitted and received in the area of the cane tip and the infrared signals are emitted and received in the area of the handle. Even if the drawing gives the impression that the electronic individual parts fill the entire interior of the housing 2, there is still enough space in the floor to accommodate further electronic circuits in the blind staff 1, which can convey further information to the blind person. The ultrasound device 10 shown in FIG. 2 as an electrical circuit has in its center a piezo element LS which emits the desired high ultrasound signals. In order to use the energy of the battery sparingly, the circuit does not provide a sinusoidal signal, but a rectangular one. The sound is generated by an astable multivibrator, the elements and their connection can be seen in the circuit diagram. Since the piezo element represents a capacitive load, relatively large peak currents flow during the signal edges. For this reason, three of the cut trigger inverters contained in the switching element TC40 106 are connected in parallel and provided with an output stage each made up of two tun transistors T1 and T2 or T3 and T4. The switching elements N4 to N6 inventory the signal supplied by the switching elements N1 to N3 and thus form a "bridge". A 9V battery provides an amplitude of 15 Vpp and a reproducible frequency of 21 kHz.

3 shows the infrared transmitter, the infrared device 13. The transmitter is constructed with a type 567 tone decoder circuit. This well-known integrated circuit is used somewhat unusual here, but for this special purpose it is much more suitable than a simple circuit with a timer IC 555 mainly because a VCO and a special switching stage are built into the type 567 circuit and this circuit has better linearity. The 50 mVpp audio signal is amplified by transistor T1 and then used to modulate integrated circuit 567. The output 6 of the circuit 567 is a trigger input, so that the audio signal is superimposed on a high-frequency signal of approximately 50 kHz. The result of this superimposition is a pulse width modulation of the rectangular output signal. Since the rest of the integrated circuit 567 can be used as a buffer, it is possible to control the light-emitting diode LD 271 directly from the output of the integrated circuit 567. The peak current is about 10 A and the transmission frequency can be varied between 25 and 40 kHz using the potentiometer T2.

Fig. 4 shows a commercially available receiver that is used as a receiver 7 for the ultrasonic signals. The details of the receiver result from the circuit diagram and require no further explanation.

FIG. 5 shows the stage counting unit 10, which compares the received infrared signals with the transmitted ones and assigns a special acoustic signal to each individual unevenness in the floor. The timer IC 555 is shown in detail in FIG. 5, which works as an astable multivibrator with a frequency of 3.33 Hz. The period is therefore 0.3 s. This time corresponds exactly to the time by which the infrared signal spreads more slowly towards the obstacle. As soon as an obstacle is detected, the counter is started. The counters IC 2 and IC 3 connected in series receive a reset signal which resets to zero. The output signal from IC 1 is at the clock input of the first counter IC 2 and is now processed by it. After 0.3 s the first signal is activated and after that every further clock pulse after 0.3 s activates the next higher point. The distance from your own location to the obstacle is indicated by one or two signals (sound). The counter IC 2 counts the height or depth of the steps and emits up to ninety tones. The first counter IC 4017 corresponds to an LD 271 and the second counter IC 4017 corresponds to an LD 803.

Claims

Claims:

1. cane (1) with at least one transmitter (6) which transmits the signals, at least one receiver (7) which receives the signals, at least one computer (10) which compares the transmitted signals with the received signals and assigns the difference at least one comparison signal, and at least one loudspeaker (15) which emits this comparison signal as an acoustic signal.

2. cane (1) according to claim 1, characterized in that the emitted and the received signals are ultrasonic signals and the computer compares the intensity and / or quality of the emitted signals with the intensity and / or quality of the received signals and the intensity and / or quality difference assigns a first comparison signal.

3. cane (1) according to claim 2, characterized in that the loudspeaker emits the first comparison signal as a signal with a corresponding pitch and / or timbre.

4. cane (1) according to one of the preceding claims, characterized in that the transmitted and the received signals are ultrasonic signals and the computer the times of the transmitted Comparing signals with the times of the received signals and assigning a second comparison signal to the time difference.

5. cane (1) according to claim 4, characterized in that the speaker emits the second comparison signal as a signal with a corresponding volume.

6. cane (1) according to one of the preceding claims, characterized in that the transmitted and the received signals are infrared signals and the computer compares the intensity and / or the time of the transmitted signals with the intensity and / or the time of the received signals and assigns a third comparison signal to the intensity or time difference.

7. cane (1) according to claim 6, characterized in that the speaker (15) emits the third comparison signal as a signal with a corresponding pitch.

8. cane (1) according to claim 6 or 7, characterized in that the computer has a counter which assigns a fourth comparison signal to each projection when the stick (1) passes by projections.

9. cane (1) according to any one of the preceding claims, characterized in that a further receiver receives the inductive scatter pulse of any telephone and the pulse strength assigns a fifth comparison signal and the speaker emits this fifth comparison signal as an acoustic signal.

10. cane (1) according to claim 9, characterized in that the loudspeaker (15) emits the fifth comparison signal with a volume corresponding to the intensity.

11. cane (1) according to one of the preceding claims, characterized in that it has a clock with a time announcement.

12. cane (1) according to one of the preceding claims, characterized in that the acoustic signals are at least partially speech signals.