GB2469793A

GB2469793A - Hearing assistance amplification device with headset and microphone detection

Info

Publication number: GB2469793A
Application number: GB0907055A
Authority: GB
Inventors: John Christopher Rohde; Bobby Duane Taylor
Original assignee: HEARING PRODUCTS INTERNAT Ltd
Current assignee: HEARING PRODUCTS INTERNAT Ltd
Priority date: 2009-04-24
Filing date: 2009-04-24
Publication date: 2010-11-03
Anticipated expiration: 2029-04-24
Also published as: GB2469793B; GB0907055D0

Abstract

A hearing assistance amplification device detects the proper insertion of headset and microphone jack plugs into respective input jacks in a personal listener 3 in order to prevent a potential sound shock to users of personal listeners and induction loop amplifiers. The amplification device comprises a first input jack 15 for connecting a headset (e.g. headphone, earphone, ear bud, ear piece or inductive loop) and a second input jack 14 connecting a microphone or line level signal input. Electronic circuitry is provided for the amplification of audio or electromagnetic signals input via the second input jack 14 and includes a volume control 13 for adjusting the amplification level of these signals. The electronic circuitry is programmed to detect connection at the first 15 and second 14 input jacks and to reduce the amplification, and hence the output volume, when connection at either input jack is not detected. The electronic circuitry may include at least one visual indicator 11 and may be programmed to activate it (e.g. by illumination or intermittent illumination) when connection at either input jack is not detected.

Description

A Hearing Assistance Amplification Device with Headset and Microphone Detection The present invention concerns assisted listening amplification devices as are commonly used by individuals who have a hearing disability. One type of such device, referred to here as "a personal listener" can be used by individuals with hearing impairment who want to remove their hearing aid and listen to sound by means of a headset or headphones plugged into such a personal listener. In other scenarios the user may wear their hearing aid, put the hearing aid on the T position (T-coil) and then use the personal listener connected to a small inductive neck loop worn around the user's neck. Another type of such device is an inductive loop amplifier which is used with/connected to an inductive loop installed around a given listening area, such as a perimeter of a room. When a personal listener is used in the second manner mentioned above it is, effectively, being used as an inductive loop amplifier, but for personal use rather than for all individuals wearing hearing aids with T-coil function in a given listening area.

Personal listeners are popular with hearing aid users because, when used without a hearing aid, namely with headset or headphones or similar, they give a more realistic sound to the user compared to a hearing aid. To overcome the user's hearing impairment personal listeners are capable of very high sound levels (100dB and higher).

A large majority of users of these various types of assisted listening amplification devices are elderly and/or have mobility and visual impairments or in some cases are completely blind. In addition, they often have some diminished mental capacity for using electronic devices.

A common problem, particularly with personal listeners, is that the user may not properly insert the plug in connector of the headset or headphone, or of the relevant microphone or alternatively of the signal input from the relevant audio equipment, and then, thinking that the device is not working, turn the volume up to the highest setting. A social service worker or an assistant at a hearing impairment centre may do the same and, without understanding the risks, turn the volume up to the highest level without properly inserting the headset or headphone or microphone plug. Then when the user subsequently plugs in the headset, headphone or microphone they will get a very loud sound shock (100dB and higher in some cases).

Most modern personal computers and many audio visual devices have a jack sensing circuit and software to detect if a headset or microphone plug is inserted into the relevant jack. The primary reason for these detection circuits is to allow the device to self adjust for various different types of headsets, headphones and microphones, such as the various impedances of different types of headsets or headphones.

In addition to the many electronic devices that have headset jack sensing capability there are currently many integrated circuit (IC) manufacturers that have added the jack sensing (also known as headset or headphone sensing) function to their lOs. However, as mentioned, this function is primarily for adapting the system to various types of headsets, headphones, or microphones (impedances or wiring layout), or else for shutting down the amperage consumption of the IC when any of these devices are removed, for example in order to extend battery life.

Currently, the personal listeners and induction loop amplifiers used by people with hearing impairment do not have any means for jack sensing for headset, headphone, or microphone insertion.

An object of the present invention is to prevent a potential sound shock to users of personal listeners and induction loop amplifiers in the circumstances outlined above.

In accordance with the invention such a device will have means for detecting the proper insertion of a headset, headphone, ear bud or similar or inductive neck loop, and of a microphone or line level signal input. If the user forgets to properly insert any of these devices and then turns the volume up to high levels, the electronics and software will instantly reduce the volume to a safe level (in milliseconds). This will eliminate the possibility of a loud sound shock to the user and potential damage to the user's hearing. Once the user properly inserts the previous mentioned devices, the user can restart the system and adjust the volume to a safe level.

More specifically, the invention provides an amplification device for hearing assistance purposes comprising a first input jack for connection of a headset or headphones or an inductive loop, a second input jack for connection of a microphone or a line level signal input, and electronic circuit means including means for amplification of audio signals or electromagnetic signals input via the second input jack and volume control means for adjusting the level of amplification of these signals, the electronic circuit means being programmed to detect connection at the first and the second input jacks and to reduce the level of amplification and hence output volume when connection at the first or the second input jack is not detected.

In preferred embodiments of any type of device in accordance with the invention, the electronic circuit means also includes at least one visual indicator and is programmed to actuate said indicator, for example by illumination or intermittent illumination of same, when connection at the first or the second input jack is not detected.

The invention will be described further, by way of example, by reference to the accompanying drawings, in which: Figure 1 is a sketch showing a typical user watching television using a personal listener with a headset; Figure 2 is a perspective view of a practical embodiment of a personal listener in its charging base (cradle) in accordance with the present invention; Figure 3 is an enlarged perspective view, from the front, of the charging cradle shown in figure 1; Figure 4 is a further enlarged perspective view, from the rear, of the charging cradle shown in figure 1; Figure 5 is a perspective view, from the front, of the personal listener shown in figure 2; Figure 6 is an enlarged perspective view of the personal listener shown in figure 5 and turned to show its bottom end; Figure 7 is a perspective view showing the rear of the personal listener or figure 5; Figure 8 is a block diagram of the electronic circuit housed within the personal listener of figures 2 to 7; Figure 9 is the software flow chart for the electronic circuit of figure 8; Figure 10 is a schematic plan view which illustrates a typical use of an inductive loop amplifier system; and Figure 11 is a circuit block diagram of an exemplary amplifier in accordance with this invention; Figure 1 shows a typical application of a personal listener 2 being used for watching television.

The personal listener 2 is shown in the user's hand and a headset 1 connected to the listener to is worn on the head and inserted into the ear canal. Other embodiments of the system could use headphones, ear buds, a behind the head headset or an inductive neck loop. An inductive neck loop is worn around the user's neck and is inserted into the personal listener 2 headset jack as an alternative to the headset. When using an inductive neck loop the user must be wearing a hearing aid and the hearing aid must be set to the T setting (Tel-coil).

Figures 2, 5, 6 and 7 illustrate an embodiment of a personal listener 3 in accordance with the invention, which is typically placed into an associated charging cradle 4, as shown in figure 2.

The cradle 4 is shown separately in figures 3 and 4.

The personal listener 3 incorporates a battery and to recharge the battery the personal listener 3 is placed into a charging bay 6 of the cradle 4 so that a direct current (DC) male plug 5 in the bay 6 is inserted into a female jack 1 6 in the bottom of the casing of the personal listener 3 (figure 6). Once a good connection between the male and female plugs 5, 16 has been made, a battery charging indicator 7 on the cradle 4 will change from off to a red colour. At the same time a battery charging indicator 12 on the personal listener 3 will change from off to a red colour. Once the battery is fully charged, the battery charging indicators 7 and 12 will change from red to a green colour. When the personal listener 3 is removed from the charging cradle 4 the battery charging indicators 7 and 12 will be turned off (not illuminated).

As shown in figure 4, on the rear of the charging bay 4 there are three jacks. The first jack 8 is for a DC power input, the second jack 9 is for a line level signal input, and the third jack is for a condenser microphone input 10. The line level signal input 9 and the microphone jack input 10 are for sending audio signals to an electromagnetic signal transmitter circuit housed inside the charging cradle 4. The line level signal for input 9 can come from any type of audio visual equipment. The microphone signal for input 10 can be from any type of condenser microphone.

The purpose of the charging cradle 4 having an electromagnetic signal transmitter circuit is so that the personal listener 3 can act as a receiver of the electromagnetic signal.

In other embodiments of the system a charging cradle may be provided without such an electromagnetic signal transmitter circuit and such a cradle would then only act as a source of DC voltage to recharge the personal listener 3. However, the provision of a charging cradle is itself an optional, but desirable feature in accordance with the invention.

The casing of the personal listener 3 has respective jacks 14 and 15, as shown in figures 2 and 5, the jack 14 being for connection of a microphone or line level input signal input and the jack being for connection of a headset, headphone, or neck loop.

In the illustrated embodiment, the user interface of the personal listener 3 consists of a system status LED 11 and a battery charging indicator LED 12, provided on the front of the casing (figures 2 and 5), a VOLUME control 13, and a TONE control 18 on one side (figure 7). The status LED 11 is off until the user requests the system to turn on by using the VOLUME control 1 3 and turning the knob clockwise until an internal switch (not shown) is activated. When the switch is closed an internal microcontroller (MCU, not shown) uses software program and electronic circuit to turn the status LED 11 to a green colour. If the battery voltage drops below 2.7 volts DC, then the MCU uses as software program and electronic circuit to change the status LED 11 to a red colour.

If the user does not correctly insert a headset, headphone, or neck ioop into the headset jack 15, the MCU uses software program and electronic circuit to change the colour of the status LED 11 to a flashing red colour to warn the user that an error has occurred. If the user does not correctly insert a microphone or line level input signal into the jack 14, then the MCU will use software program and electronic circuit to change the colour of the status LED 11 to a flashing red colour to warn the user that an error has occurred. The purpose of this software and electronic circuit is to protect the user from a potentially harmful sound shock.

To adjust the VOLUME level the user moves the control knob 13. Numbers on the control knob indicate relative sound level to the user. In other embodiments of the device of the invention, the VOLUME control could be a linear potentiometer, a rotary potentiometer, or a push button that sends a signal to the MCU.

The battery charging indicator LED 12 is used to advise the user of the battery status. If the battery voltage is equal to or lower than 2.7 volts DC then the MCU, using the software program and the electronic circuit, will change LED 12 to a flashing red. If the battery is being recharged by an external DC power source, then the MCU, using the software program and the electronic circuit, will change LED 12 to a solid red. If the battery is fully recharged by an external DC power source, then the MCU, using the software program and the electronic circuit, will change LED 12 to a solid green.

As shown in figure 7 the rear personal listener 3 is provided with a belt clip 17. The belt clip 17 is used when a user wants to move around and wear the personal listener. Typically a user would be outside and using the personal listener 3 to amplify the voices or sounds in the area.

When the user wants to change the TONE of the sound the user pushes the slide switch 1 8 up for high TONE. For mid-point TONE the user pushes the slide switch 18 to the centre position.

For lower TONE the user pushes the slide switch 18 to the bottom position. In other embodiments of the system, the TONE control could be a linear potentiometer, a rotary potentiometer, or a push button that sends a signal to the MCU.

In this embodiment of the system, the user interface consists of various LEDs 7, 11 and 12.

However, other embodiments could use a liquid crystal display (LCD) or bar graph LEDs or a combination of both. In addition, the user interface could also include an audio indication such as a piezo-electric transducers or speaker to alert the user to the system status.

The purpose of the user interface is to give visual and audio feedback to the user about the system status.

The circuit block diagram shown in figure 8 outlines the building blocks of the electronic circuit inside the personal listener device 3. The circuit includes a microcontroller 29 programmed with software. The circuit can receive electromagnetic signals at 19 and then pre-amplify and condition them. In addition to receiving electromagnetic signals, the circuit can also receive various microphone or other audio signal inputs and a pre-amplifier 20 amplifies low level microphone signals and conditions them for further use. A Tone and automatic gain circuit (AGO) 21 controls the level of the audio signal inputs and adjust the tone. Once the signal has passed through the Tone and AGO stage 21, the signal is passed to a power amplifier stage 22. The power amplifier 22 then passes the signal to the headset amplifier circuit 23 and conditions for use by various headsets and inductive neck loops.

A microphone or line level signal input detection circuit 24 sends a signal to the MOU 29 if a valid microphone or line level signal is present. If the MOU does not receive this signal then the software controlling the MOU will set an error flag and lower the volume level to 0dB by using the digital volume control 26. The tone is controlled digitally at 25 by the MOU 29. A headset or neck loop input detection circuit 27 sends a signal to the MOU 29 if a valid headset or neck loop is present. If the MOU does not receive this signal then the software controlling the MOU will set an error flag and lower the volume level to 0dB by using the digital volume control 26. Because the system is using an MOU that is controlled by software, the time required from detecting a microphone or headset and adjusting the volume to avoid damaging the user's hearing is in milliseconds.

Some embodiments of the system/device in accordance with the invention incorporate means to allow for two-way communication between multiple personal listeners. This can be accomplished by including an electromagnetic transceiver circuit 28, as shown in figure 8. Two-way communication is useful for users who are in a group setting where several people have a hearing impairment and desire to communicate and volume levels are easy for them to understand.

A data acquisition port 31 is provided and is used to collect user data when the system requires maintenance.

In this embodiment of the system, a switch mode DO power source 33 is required to provide 5 volts DO to the system. An external alternating current (AO) or DO power source (as from the cradle connection in bay 6) is required to connect with the battery recharge circuit 34 so that the battery can be recharged.

The software that controls the MCU is shown in figure 9 in the form of a flow chart. Upon the first time power is applied to the circuit, the system starts (35) and various basic initiations procedures are done. Once the system has initialized, the VOLUME and TONE levels are set (36). When the user moves the VOLUME knob 13 far enough to close the ON/OFF switch on the printed circuit board (not shown), the software detects the change (37) and checks the status of the ON/OFF flag (38). If the flag is clear (=0) then the software sets (=1) the ON/OFF flag and turns the power to the system on 39. If the flag was already set, the software knows that the system was already on and that the user wants to turn the system off. The software then clears the ON/OFF flag and turns the system off (43).

Once the personal listener 3 is switched on and the user wants to increase or decrease the volume level, the user moves the VOLUME knob 13. The movement of the volume knob potentiometer on the PCBA (not shown) changes the DC voltage sent to the MCU. The MCU changes the DC voltage into a digital value (analogue to digital conversion) and the software determines what volume level the user wants to set the system to (40). The reason for using this method is so that the software is in complete control of the volume level for the safety reason which underlies the present invention. If a headset, headphone, or neck loop is not inserted into the jack 15 properly, the software (at 41) will reduce the volume to 0dB, set an error flag, and flash the status LED 11 to indicate to the user that an error condition is present (45). If a microphone or line level signal is not present at jack 14, the software (at 42) will reduce the volume to 0dB, set an error flag, and flash the status LED 11 to indicate to the user that an error condition is present 45. An instruction manual given to the user with the equipment will explain how to clear the error condition, which may be a result of non-insertion or incorrect insertion (i.e. not full insertion to correctly connect to the system) into either the jack l5or the jack 14.

If a headset, headphone, or neck loop is present at jack 15 and a microphone or line level signal is present at jack 14, then the software will change the VOLUME level to match the user's request (46). The software will also update the visual display (if present) to advise the user of the volume level change (47).

If the user requests a Tone level change by using the TONE slide switch 18, then the software (48) will process the request and adjust (at 49) the digital potentiometer on the PCBA (not shown) to match the user's request. The software will also update the visual display (if present) to advise the user of the tone level change 50.

The software monitors the battery voltage 51 and if the battery voltage is greater than 2.7 volts DC, then the software will loop back to 37. If the battery voltage is equal to or less than 2.7 volts, the software (51) will flash LED 1 2 and wait for 1 0 seconds. This is to warn the user that the battery is about to fail and that the system will turn off automatically. If the user does not do anything, the system will automatically shut off (53) and return to 37. If the battery voltage is not high enough, the software will not complete the start up routine.

In a typical scenario a user may turn the system (the personal listener 3) on, forget to insert a microphone (sound source) into jack 14 or forget to insert a headset or neck loop plug into jack 15, and then turn the volume up using the volume control 13. The system status LED 11 will then flash red (or other visual or audio display in other embodiments) and the volume will remain at 0dB. The system is in a "fault" state, as outlined above. The user may then have to turn the listener device 3 off and properly insert a microphone and/or a headset or loop plug before switching on again and turning up the volume. When the listener three is turned on again with correct connection of microphone and headset or loop, the software controlled MCU recognises this, the fault is cleared and the system works normally.

The foregoing is illustrative and not limitative of the scope of the invention. Variations in detail of the exterior and the internal circuit and software of the personal listener may vary in other embodiments and some possible variations have already been mentioned in the foregoing description. As mentioned, the provision of a cradle for battery charging and other purposes is optional.

The inventive concept of incorporating jack sensing to achieve volume reduction is also applicable to an inductive loop amplifier and an example of such application is now described with reference to figures 10 and 11. Other features of such inductive loop amplifier system are conventional and well-known to any person skilled in this technical field.

Figure 10 shows an example of a typical application of the inductive loop amplifier system of the invention in use. The amplifier 60 is shown on top of a television set 62. It is connected to a loop of wire 63 (shown in dashed lines) that goes around the room and forms an audio frequency antenna. The individuals shown are wearing hearing aids with a t-coil that can receive the magnetic wave signals coming from the loop antenna 63. In other words, this audio frequency antenna 63 inductively couples with the users' hearing aids in tele-coil (T-coil) function mode.

Although the amplifier 60 is not illustrated because its features are conventional, it includes conventional keypad features such as tone and volume increment and decrement buttons and visual indicators, such as light emitting diodes to indicate to the user the status of the tone and volume. A head set jack is included to enable a user to check the sound that is being amplified by the amplifier 60 as well as the usual microphone input jacks.

With reference to Figure 11, the circuitry of the amplifier 60 includes an audio pre-amplifier 130 which adjusts the microphone input. A tone control and automatic gain control circuit 1 31 adjust the bass or treble of the audio input signal and adjusts the gain of the audio input signal to avoid distortion. A power amplifier stage 132 amplifies the sound to a level that will drive the loop antenna 3. A head set amplifier circuit 133 is included so that a user can monitor (from the relevant output jack) the audio signal that is sent to the loop antenna 63. This is useful since the loop antenna 63 is often quite large and hidden from view. If the loop antenna 63 is damaged the head set function allows for a quick check when trouble shooting the system.

A digital tone control circuit 134 is used as a digital interface between the analogue circuit 131 and a microcontroller 138. A digital volume control 135 is used as a digital interface between the analogue circuit 132 and the microcontroller 138.

To avoid a user plugging in a headset with the volume at a high level, a headset detection circuit 136 will adjust the volume to a safe level when a headset connection is not detected, in comparable manner to explained in the above description in relation to a personal listener, so that a high-volume signal is not present when a headset is plugged into the system.

To update the system software and to get system information a data acquisition port and related circuitry 139 is located on the printed circuit board. To control the various visual devices, such as LEDs on the amplifier housing, a circuit 140 is included. A user input interface 142 circuit is included to interface the microcontroller 138 with the key pad and the various control switches/knobs on the amplifier housing.

A power source circuit 141 for the system receives electric power as direct current or alternating current and provides various safety features such as a fusible link and over voltage protection.

Claims

CLAIMS1. An amplification device for hearing assistance purposes comprising a first input jack for connection of a headset or headphones or an inductive loop, a second input jack for connection of a microphone or a line level signal input, and electronic circuit means including means for amplification of audio signals or electromagnetic signals input via the second input jack and volume control means for adjusting the level of amplification of these signals, the electronic circuit means being programmed to detect connection at the first and the second input jacks and to reduce the level of amplification and hence output volume when connection at the first or the second input jack is not detected.
2. An amplification device according to claim 1 wherein the electronic circuit means includes at least one visual indicator and is programmed to actuate said indicator, for example by illumination or intermittent illumination of same, when connection at the first or the second input jack is not detected.