TECHNICAL FIELD
The present subject matter generally relates to a vehicle. More particularly but not exclusively the present subject matter relates to a system to a sound device diagnostic apparatus for a vehicle horn.
BACKGROUND
In vehicles, horn is used as a sound signalling device which serves as audible warning device to alert the pedestrians, oncoming vehicles and animals on the road. It can also be used as an alarm to unauthorized access. There are different types of horn like AC horn, DC horn and air horn. In all these horns, the basic operating principle is propagation of vibration through air column resulting in sound. A typical horn consists of copper coils wound around a cylindrical ferromagnetic core which when electrically energized would generate an electromagnetic field lines along the axis of the coil and ferromagnetic core. The supply to the coil is through a pair of flexible contacts.
The aforementioned coil is assembled inside a horn assembly which also consists of resonator and diaphragm attached to a mobile nucleus which under the influence of magnetic field experiences a pull force along the axis of the coil. The mobile nucleus consists of radially extending flange like structure which directly rests on one of the flexible contact strip, when the coil is not energized. In the aforementioned coil arrangement, if coil is electrically energized, it results in exertion of downward pull force on the mobile nucleus hence the flange like structure would pull the pressurized contact strips down resulting in opening of contacts and also small displacement of resonator and diaphragm.
The opening of contact results in collapse of electromagnetic field on the mobile nucleus, so the diaphragm and resonator assembly along with mobile nucleus would move back to its original position due to the inherent elastic property of diaphragm. This motion creates vibration which is being transmitted to the tone disc and resonator. Vibration in air column creates sound. In this construction,

contact pressure between two contact strips is very much instrumental in the tonal quality of the audible warning device.
BRIEF DESCRIPTION OF THE DRAWINGS
[0005] Figure 1 illustrates a side view of the exemplary two-wheeled vehicle, in
accordance with an embodiment of the present subject matter.
[0006] Figure 2 illustrates a side view of the present subject matter with contacts
coming into contact.
[0007] Figure 3 illustrates another side view of the preset subject matter with
contacts moving away from each other.
[0008] Figure 4 illustrates a top view of the subject matter showing diaphragm of
the horn.
[0009] Figure 5 illustrates a back view of the subject matter.
[00010] Figure 6 illustrates a block diagram of the present subject matter.
[00011] Figure 7 illustrates the flow chart of the working of the present subject
matter.
DETAILED DESCRIPTION
[00012] For years, electric horn has been used in the automotive vehicles
which generates sound by the vibration of the diaphragm driven by an electromagnet. The horn typically comprises a housing with a diaphragm peripherally clamped thereto forming a chamber. The coil of the electro magnet is mounted within chamber and a flange like structure in the mobile nucleus extends axially to the coil.
[00013] Due to repeated making and breaking of contacts, there is wear of
the contacts resulting in variation of contact pressure. This might end up in variation of electrical frequency, sound frequency, and current consumption. Tuning screw is provided in most horns which can be rotated in a particular direction to restore the contact strip pressure and ensure proper working of horn. But wrong tuning of horn might result in high current consumption or open circuit condition, improper sound frequency and amplitude.

[00014] The frequency of the vehicle’s horn is usually tuned according to the
size of the vehicle. For minimizing sound pollution & audible comfort, the frequency range of the horn needs to be maintained within certain range and it is desirable to keep the frequency range of the horn constant throughout the usage or the life time of the vehicle. Additionally, depending on the type of vehicle, size etc. the magnitude of the audible sound needs to be different. This increases the variety of types of sound devices for a manufacturer increasing manufacturing complexity, cost as well as servicing & maintenance including supply for spares. Thus, there is a need to provide an improved sound device for a vehicle overcoming all problems cited above & others in known art.
[00015] Hence, the present subject matter provides a sound device diagnostic
apparatus (600) for the horn used in the vehicle. The present subject matter also provides a device and method of tuning the vehicle horn to correct the tuning problem caused over a period of time due to wear and tear of the contacts of the horn. Thus, through the use of the present subject matter ensures proper tuning based on the present status of the horn.
[00016] Another embodiment of the subject matter provides a sound device
diagnostic apparatus (600) for the horn of the vehicle where the horn is energized for a fixed period of time after which the frequency of the horn is compared with a desired frequency range. The frequency of the horn is measured using a controller circuit.
[00017] Yet another embodiment of the present subject matter provides a
tuning screw which is to be used in order to tune the horn depending on the
command given by the sound device diagnostic apparatus (600) after energizing the
horn for said fixed period of time. The sound device diagnostic apparatus (600)
provides commands or indication to the user in order to tune the horn.
[00018] Still another embodiment of the present subject matter provides
sound device diagnostic apparatus (600) comprising a controller, a current sensor,
plurality of output pins, a test start switch and plurality of activating means.
[00019] Yet another embodiment of the present subject matter provides said
controller comprising an analog to digital convertor channel. The analog to digital

convertor channel computes the current which is consumed by the horn from the output of the current sensor during the energizing process. The analog to digital convertor channel calculates the electrical frequency of the current waveform of the horn in order to determine the horn quality.
[00020] Another embodiment of the present subject matter provides a
plurality of output ports and each of the plurality of the output ports are connected to the indicating units. Each of the plurality of the output ports receive the information from the controller and the indication corresponding to the processed value to the frequency of the energized horn thereby the indicating unit indicates the action to be performed by the user in order to tune the horn for proper functioning of the horn at the desired level of the frequency.
[00021] Still another embodiment of the present subject matter is to provide
plurality of indication signal given out by the sound device diagnostic apparatus (600) where each of the indication signal is represented by a colored light by illuminating corresponding LEDs. Each of the LED has a color to indicate the signal to the user. For e.g. A green color LED light indicates that the condition of the horn is satisfactory and no alteration or tuning of the vehicle’s horn is required. A red LED light indicates that the horn is not tuned to the desired level of operating frequency and hence require tuning. A blue color LED corresponds that the tuning is required where the tuning screw is rotated in a clockwise direction and a yellow color LED corresponds that the tuning is required and the tuning screw is to rotated in the anti-clockwise direction. The rotation indication for corresponding LED can be interchanged as per the user.
[00022] Another embodiment of the present subject matter provides a test
start switch to start the process of diagnosis of the vehicle horn. Further, a plurality of activating means is provided in order to identify the type of horn which needs diagnosis and the activating means can be switches to select a horn or it can be display touch sensitive button on touch sensitive screen to select the horn. The said activating means enable selection of a type of horn based on frequency of operation like a low tone horn or a medium tone horn or a high tone horn. Thus, the sound device diagnostic apparatus (600) described in the present invention is capable of

being diagnostic different types of horn based on the type of tone. Such a sound device diagnostic apparatus (600) can be effectively utilized for maintaining optimum horn characteristics in any type of vehicle, for example, a saddle type vehicle such as a scooter, a motorcycle, a moped etc., a multi-wheeled vehicle including a three-wheeled vehicle, a four-wheeled vehicle etc. The sound device diagnostic apparatus (600) of the present invention can be manufactured and sold as an accessory, which is either capable of being suitably integrated with the vehicle, or held separately as a servicing tool.
[00023] These and other advantages of the present subject matter would be
described in greater detail in conjunction with the embodiment of an scooter type two wheeled vehicle in the figures in the following description.
[00024] Fig. 1 illustrates a left side view of an exemplary motor vehicle
(100), in accordance with an embodiment of the present subject matter. The vehicle (100) illustrated, has a frame member (105). In the present embodiment, the frame member (105) is step-through type including a head tube (105A), and a main frame (105B) that extend rearwardly downward from an anterior portion of the head tube (105A). The main frame (105B) extends inclinedly rearward to a rear portion of the vehicle (100).
[00025] The vehicle (100) includes one or more prime movers that are
connected to the frame member (105). In the present implementation, one of the prime movers is an internal combustion (IC) engine (115) mounted to the frame member (105). In the depicted embodiment, the IC engine (115) is mounted to a structural member (135) that is pivoted to the frame member (105). In one embodiment, the structural member (135) is a rigid member made including metal. The vehicle (100) also includes another prime mover, which is an electric motor (120). In a preferred embodiment, the electric motor (120) is hub mounted to one wheel of the vehicle (100). In another embodiment, one or more than one electric motor is mounted to wheels or to the frame of the vehicle. In the depicted embodiment, the vehicle (100) includes at least two-wheels and the electric motor (120) is hub mounted to the rear wheel (125) of the vehicle. A front wheel (110) is

rotatably supported by the frame member (105) and is connected to a handle bar assembly (130) that enables maneuvering of the vehicle (100).
[00026] Further, the vehicle (100) includes a high capacity on-board battery
(not shown) that drives the electric motor (120). The high capacity battery may include one or more high capacity battery packs or one or more low capacity cells. The high capacity battery can be disposed at a front portion, a rear portion, or at the center of the vehicle (100). The high capacity battery is supported by the frame member (105) and the vehicle (100) includes plurality of body panels, mounted to the frame member (105) for covering various components of the vehicle (100). The plurality of panels includes a front panel (140A), a leg shield (140B), an under-seat cover (140C), and a left and a right-side panel (140D). A glove box may be mounted to a leg shield (140B).
[00027] A floorboard (145) is provided at the step-through portion defined
by the main tube (105B). A seat assembly (150) is disposed rearward to the step-through portion and is mounted to the main frame (105B). The seat assembly (150) that is elongated in a longitudinal direction F-R of the vehicle (100) enables the user to operate the vehicle in a saddle ride-type posture. One or more suspension(s) connect the wheels (110), (125) to the vehicle (100) and provide a comfortable ride. The vehicle (100) comprises of plurality of electrical and electronic components including a headlight (155A), a taillight (155B), a starter motor (not shown), a horn etc. Also, the vehicle (100) includes a master control unit (not shown) that takes control of the overall operation of the vehicle (100) including the function of the IC engine (115), the electric motor (120), charging of the batteries from a magneto/integrated starter generator (ISG), driving of loads by the magneto/ISG, charging of the high capacity batteries by the electric motor operating in generator mode, and any other operations associated with the operation of the vehicle (100). The vehicle (100) shown in fig. 1 is an exemplary vehicle and the present subject matter can be used in a two-wheeled vehicle, three-wheeled vehicle or a four-wheeled vehicle.
[00028] Fig.2 illustrates a side view of an internal structure of the horn (200)
or sound device used in the vehicle. A horn (200) typically has a circular cross-

section body with a stepped outer flange around the opening to provide maximum area for the acoustics to function properly. A diaphragm (203) is secured around the outer portion of the horn’s periphery by means of annular clamps (not shown). A tone disc (202) is provided externally of the body of the horn (200) and is spaced from the diaphragm (203) by spacing means such as a spacer. (since it has only a rivet which separates the diaphragm and tone disc).
[00029] The diaphragm (203) is connected to a mobile nucleus (213) for the
movement in up and down direction when a coil assembly (212) is energized using a power source such as a battery (208) A contact breaker assembly mounted in the fixed nucleus chamber comprises a first contact (204) and a second contact (205). Both the first and the second contacts are connected to electrically conductive arm (206,207). First contact (204) is electrically connected to the first conductive arm (206) and the second contact (205) is electrically connected to the second conductive arm (207).
[00030] The first conductive arm (206) is connected with a positive terminal
of a battery (208) and a negative terminal of the battery (208) is grounded to first grounding point (216). The second conductive arm (207) is connected to a wire coil wounded helically around the cylindrical surface which forms the coil assembly (212). The wire coil, in turn, is extended and connected to a horn switch (209). One terminal of the horn switch (209) is connected to the coil assembly (212) and the other terminal of the horn switch (209) is grounded to second grounding point (217). The first grounding point and the second grounding point are connected to a common ground point in vehicle. The horn switch (209) can be switched ON or switched OFF according to the user’s requirement while driving.
[00031] The diaphragm (203) and the mobile nucleus (213) sandwiches a
striker (214). When the horn switch (209) is turned ON, current flows through the coil assembly (212) which creates a electromagnetic force which pulls the mobile nucleus (213) downwards. As a result, second conductive arm (207) makes contact with the striker (214) and the coil assembly (212) gets de-energized. As the coil is de-energized, striker plate moves in the upward direction away from the second

conductive plate (207) which in turn results in current flow and the same process is repeated continuously to generate noise.
[00032] Fig. 3 illustrates a side view of the horn (200) when the horn switch
(209) is in closed condition. The coil assembly (212) gets energized and strikes the mobile nucleus (213). This movement of the coil assembly (212) caused the diaphragm to move in a vibrating motion in up and down direction. The energy drawn by the horn (200) gets measured by a current sensor and sensor output is electrically connected to the controller (601) (refer fig. 6) which computes the frequency and it is compared with predefined values.
[00033] Fig.4 illustrates a top portion of the horn (200). The diaphragm (203)
surrounding the tone disc (202) extends towards the circular frame (401) provided on the periphery of the horn (200). The horn (200) is mounted on a frame or a bracket provided on the vehicle using a mounting plate (403). the mounting plate is provided with a mounting mean (404) to allow a fastening member to removably attach on the vehicle frame or the bracket where the horn (200) is intended to be mounted.
[00034] Fig.5 illustrates the bottom or back portion of the horn (200). The
back portion of the horn (200) comprises of a base cover (501) which is of similar
diameter as that of the diaphragm (203) and encloses the horn assembly. The base
cover (501) is molded into multiple tier shape. Plurality of connectors (503,504) are
disposed on the base cover (501) for the purpose of mounting on to any surface.
The base cover (501) also comprises of tuning screw (502) for tuning the horn (200)
to match with the desired level of the frequency. The mounting plate (403) is affixed
to the base cover with the help of a fastening means (505) such as a threaded crew.
[00035] Fig. 6 illustrates the constructional aspect of the sound device
diagnostic apparatus (600) for the vehicle horn (200). The present subject provides a sound device diagnostic apparatus (600) which is configured to mainly comprise of a controller (601) which computes the electrical frequency of horn (200) based on which tuning is performed. The Controller (601) is connected with a plurality of horns which are low tone horn, mid tone horn and high tone horn. A user can select any one of the plurality of horns available for testing and tuning purpose. In order

to select the horn (200) a dedicated activating means is given for every horn. A low tone horn has first activating means (605), a mid-tone horn has second type (606) switch and a high tone has a third activating means (607). As per another embodiment, the switches may be display type e.g. LCD touch screen display with the interface as well as the indications being configured on a instrument cluster of the vehicle or the like.
[00036] A test start switch (602) connected to the controller (601) in order
to initiate the diagnosis of the horn (200) after selecting one of the horn (200) by
the user / service mechanic using the activating means. The horn (200) is provided
with current supply from a power supply (604) such as a battery. When the test
switch is pressed, the horn (200) gets energized by the battery for a predetermined
period e.g. 500 ms and the current drawn is measured by the current sensor (608)
which is connected between the horn (200) and the power supply (604). The current
sensor (608), then, sends the data to the controller which comprises a current to
voltage converter which converts the current signal into voltage signal. Since the
converted output voltage signal is in analog waveform, an analog to digital
convertor is provided in the controller (601) which rectifies the analog signal into a
digital signal. The controller (601) evaluates the frequency of the current drawn by
the horn (200) and it is then compared with a predetermined frequency.
[00037] In order to indicate the malfunctioning or undesirable functioning of
the horn (200), the controller (601) outputs an output signal depending on the basis of the predetermined frequency. The controller (601) is electrically connected to plurality of indicating units such as multicolored LEDs (603) to indicate working condition of the horn (200). If the frequency drawn by the horn (200) is same as the predetermined frequency to be achieved by the selected horn (200), then color 1 e.g. the green LED will glow. But when the frequency of the current drawn by the horn (200) is not matching with the desired frequency to be achieved by the selected horn (200) then color 2 e.g. a red LED starts glowing.
[00038] The frequency of the current drawn by the horn (200) may be more
or less when compared to the desired level of frequency to be achieved for which two additional LEDs are provided. When the frequency of the horn (200) is

substantially equal to the predetermined desired frequency, then along with red LED, one more LED starts glowing depending on whether the frequency is more or less compared to predetermined frequency. If the frequency of the current taken by the horn (200) is more than the predetermined frequency then along with the red LED, a blue LED starts glowing indicating the user to rotate the tuning screw in anti-clockwise rotation whereas when the frequency of the horn (200) is less than the desired value level then along with the red LED a yellow LED starts glowing to indicate the user that the tuning screw needs rotation in clockwise direction. After tuning in the prescribed direction, the process can be repeated by pressing the start switch to check the status of horn (200).
[00039] Fig. 7 illustrates the method of performing the diagnostic test of the
horn (200) of the vehicle in order to correct the frequency of the horn (200) using a tuning screw. The horn (200) is mounted onto the test PCB board in step 701 and the horn (200) is connected to the power supply source such as a battery in step 702. A plurality of activating means are given allowing user to select one of the horns out of a low tone horn, a mid tone horn and a high tone horn in step 703. A start or start switch is provided to start the diagnostic test of the selected vehicle horn (200) in step 704. After pressing the start switch the selected horn (200) gets energized for a predetermined time(~500ms) in step 705 and after energizing the horn (200), the current frequency is measured using a current sensor which is connected in series with horn (200) in step 706.
[00040] The signal received by the current sensor is sent to analog to digital
convertor after converting from current signal to voltage signal using a current to voltage convertor and then the analog voltage signal is converted to digital voltage signal using an analog to digital convertor. The converted signal is then sent to the controller where the current frequency is computed and it is compared with a predetermined value chosen by the user / manufacturer and checked whether the current frequency is within the specification or not in step 707. If the current frequency is within the desired level, then the green LED starts glowing in step f713 otherwise the red LED starts glowing 714 along with one more LED depending on the current frequency exceeding or frequency falling short of.

[00041] If the frequency is greater than the desired level of frequency, then
the blue LED starts glowing in step 709 to indicate the user that the turning screw is to be rotated in anti-clockwise direction in step 711. When the frequency is lower than the desired value of the frequency (in step 708) to be achieved then the yellow LED starts glowing to indicate the user to rotate the tuning screw in a clockwise direction in step 710.
[00042] The tuning screw, which is provided on the back cover is utilized for
tuning the mismatch of the frequency of the horn (200) and the desired frequency set by the controller (601). The controller (601) also measures the current consumption.

We claim:
1. A sound device diagnostic apparatus (600) comprising:
one or more activating means (605,606,607) to select a horn (200); a start switch (602) to start said sound device diagnostic apparatus (600); a power supply (604) electrically connected to said horn (200) and a current sensor (608); a controller (601) configured to receive a frequency signal of said horn (200) measured by said current sensor (608); one or more output source to give an output depending on a compared value between said frequency signal and a predetermined frequency signal ; and said controller (601) enables said one or more output source based on said predetermined frequency signal to indicate a tuning direction for a tuning screw .
2. The sound device diagnostic apparatus (600) as claimed in claim 1, wherein said horn (200) is a horn configured with at least one frequency zone low frequency horn, a medium frequency horn or a high frequency horn.
3. The sound device diagnostic apparatus (600) as claimed in claim 1, wherein said one or more activating means (605,606,607) to select said horn is a first activating means (605), a second activating means (606) and a third activating means (607).
4. The sound device diagnostic apparatus (600) as claimed in claim 1, wherein said one or more output sources are a plurality of LED (603).
5. The horn diagnostic apparatus (600) as claimed in claim 1 and claim 4, wherein said one or more output sources are a red LED, a green LED, a blue LED and a yellow LED.
6. A method of tuning a horn (200) using a sound device diagnostic apparatus (600) comprising the steps:
selecting a horn (200) using a activating means (605,606,607);
energizing said horn (200) using a power supply (604);
measuring current consumed by a current sensor (608) during said
energizing of said horn (200);
comparing a current frequency with a predetermined frequency signal
through controller (201); and

glowing one or more output sources after said comparing of current frequency with a predetermined frequency. 7. The method of tuning a horn (200) using a sound device diagnostic apparatus (600) as claimed in claim 6, wherein said activating means (605,605,607,608) selects a low tone, mid tone or a high tone horn.