A special vehicle horn integrated control system and method

Abstract

This invention discloses an integrated control system and method for special vehicle horns, comprising a cab-end control device and a horn relay-end execution device. The cab-end control device includes a first microcontroller, a first communication module, a first status detection unit, an horn control unit, and a user interaction unit; the relay-end execution device includes a second microcontroller, a second communication module, a button status detection unit, and a switch execution unit. The system supports bidirectional synchronous control: when the horn is activated or deactivated, the cab-end device is activated or deactivated synchronously; conversely, the deactivation is also activated. The normally open contact of the switch execution unit can be selectively connected to either the horn control unit or the horn amplification control terminal to achieve control path switching. Wired and wireless dual-mode communication is supported between the cab-end and the relay end, with wired communication being preferred. When the system is off, the relay end is in a low-power standby state, and the original vehicle horn button controls the original vehicle horn; when the system is on, the relay end is activated, the switch execution unit switches the path, and the original vehicle horn button controls the horn amplification switch. This system allows the driver to operate the horn without taking their head off the steering wheel.

Description

Technical Field

[0001] This invention relates to the field of electrical control technology for special vehicles, specifically to a system and method for integrating and controlling a special vehicle alarm with the vehicle's original horn button. Background Technology

[0002] Police cars, ambulances, fire trucks, rescue vehicles, and other special vehicles often require siren retrofitting after purchase. In existing technology, the siren system is independent of the original vehicle's horn system. Drivers need to use a handheld remote or center console to control the siren's sound while driving, resulting in one hand being off the steering wheel, posing a serious safety hazard. Some retrofit solutions simply add extra buttons, failing to fundamentally solve the problem of ease of operation.

[0003] After studying the horn circuits of multiple car manufacturers, it was found that the vehicle horn control relay simultaneously contains a 12V / 24V positive terminal, the original car horn button control signal, a 12V / 24V negative terminal, and a horn output pin. This provides a circuit basis for the design of an integrated control system.

[0004] Furthermore, in existing retrofit solutions, there is a lack of flexible status synchronization mechanism between the cab-side control device and the alarm. Either the alarm can only control the cab-side device, or the cab-side device can only control the alarm, making it impossible to flexibly choose according to user habits and installation requirements. Summary of the Invention

[0005] This invention aims to provide a special vehicle horn integrated control system and method, which enables the horn to be amplified using the original vehicle steering wheel horn button when the horn is activated, allowing the driver to operate the horn without taking their hands off the steering wheel, thus improving driving safety; it also supports bidirectional synchronous control and dual-end control paths to adapt to different modification scenarios and user habits.

[0006] The present invention adopts a split architecture, including a cab-end control device and a horn relay-end actuator.

[0007] The cab-side control device includes a first microcontroller, a first communication module, a first status detection unit, an alarm control unit, and a user interaction unit (including a display screen and control buttons). The device supports two power supply methods: it can be powered by the special vehicle alarm (first mode), or it can be independently powered by the vehicle's ACC power supply or constant power (second mode). The first status detection unit is used to detect the operating status of the special vehicle alarm and generate corresponding status signals; the alarm control unit is electrically connected to the special vehicle alarm's loudspeaker control terminal and is used to output control signals to control the alarm's loudspeaker switch.

[0008] The horn relay actuator is powered by the vehicle's constant power supply and includes a second microcontroller, a second communication module, a button status detection unit, and a switch execution unit. This device is normally in a low-power standby state, only entering working mode upon receiving a wake-up signal. The button status detection unit is used to monitor the original vehicle horn button's operation signal in real time.

[0009] The switch execution unit uses a single-pole double-throw relay or a MOSFET electronic switch chip. Its control terminal is electrically connected to the output terminal of the second microcontroller, its common terminal is connected to the original vehicle horn button signal line, its normally closed contact is connected to the original vehicle horn control terminal, and its normally open contact can be selectively connected to the alarm control unit or directly connected to the special vehicle alarm amplification control terminal.

[0010] This invention supports two synchronization modes, which users can select through the user interaction unit according to their actual needs:

[0011] Mode 1 (Active Alarm): When the special vehicle siren is activated, the control device in the driver's cab is activated simultaneously; when the special vehicle siren is deactivated, the control device in the driver's cab is deactivated simultaneously. This mode is suitable for scenarios where it is desirable to retain the original siren's on / off habits.

[0012] Second mode (cab-side active): When the cab-side control device is turned on, the special vehicle alarm is turned on simultaneously; when the cab-side control device is turned off, the special vehicle alarm is turned off simultaneously. This mode is suitable for scenarios where it is desirable to centrally control all equipment from the cab.

[0013] The normally open contact of the switch actuator can be selected from one of the following two control paths based on the actual installation location of the special vehicle alarm:

[0014] Path 1 (cab control): When the alarm is installed close to the cab, the normally open contact is connected to the alarm control unit, which receives the button signal and controls the alarm to amplify its sound.

[0015] Path 2 (Relay Terminal Control): When the alarm is installed close to the relay terminal, the normally open contact is directly connected to the alarm amplification control terminal, and the horn relay terminal actuator directly controls the alarm amplification, resulting in a faster response speed.

[0016] The cab-side control device and the horn relay actuator establish a communication connection via a first communication module and a second communication module. This communication connection supports both wireless and wired communication. When a wired communication connection is established and both devices are powered on, wired communication is prioritized for data exchange; when wired communication is unavailable, wireless communication is used to ensure system reliability.

[0017] The working principle of this invention is as follows:

[0018] State 1 (System Off): When the active party (the alarm in the first mode and the cab in the second mode) is off, the cab control device is off (first mode) or the alarm is off (second mode). The horn relay actuator is in a low-power standby state, the normally closed contact of the switch actuator is open, and the original vehicle horn button only controls the original vehicle horn.

[0019] State Two (System On): When the active device is in the on state, the driver's cab control device is turned on (first mode) or the siren is turned on (second mode), sending a wake-up signal to the horn relay actuator. After the horn relay actuator is awakened, the switch actuator operates, disconnecting the normally closed contact and opening the normally open contact. The button status detection unit monitors the original vehicle horn button's action signal in real time and transmits the button signal to the siren control unit through the second communication module, or directly to the special vehicle siren amplification control terminal through the normally open contact of the switch actuator. When the driver presses the original vehicle horn button on the steering wheel, the siren amplifies.

[0020] The present invention has the following beneficial effects:

[0021] Enhanced driving safety: The driver can keep their hands on the steering wheel at all times and operate the alarm by pressing the original car horn button, eliminating the need to operate the remote control and avoiding the need to take one hand off the steering wheel.

[0022] Two-way synchronous control: Supports two synchronization modes: alarm active and cab active. Users can choose flexibly according to their usage habits and vehicle modifications, which improves the applicability of the system and the user experience.

[0023] Centralized control capability: In the active mode at the cab end, users can centrally control the alarm switch through the control device at the cab end, without having to reach out to operate the original vehicle alarm switch, further improving convenience and safety.

[0024] High installation flexibility: It supports two control paths: cab-side control and relay-side control. The optimal control scheme can be selected according to the actual installation location of the alarm, adapting to the modification needs of different vehicle models.

[0025] Low power consumption design: The relay-side actuator consumes less than 1 milliwatt in standby mode, without consuming the vehicle's battery.

[0026] Easy installation: It prioritizes wireless communication, requiring no modification to the original vehicle wiring harness. Only modules need to be installed at the cab end and the relay end respectively; it also supports wired communication, adapting to different modification environments.

[0027] Status visualization: The cab is equipped with a display screen that can display information such as connection status, voltage, temperature, and fault codes in real time.

[0028] High reliability: Supports both wireless and wired modes, with wired communication being prioritized to ensure stable system operation.

[0029] Highly scalable: Based on a microcontroller platform, it can be expanded to include functions such as integration with fleet management systems and OTA upgrades.

[0030] High fault tolerance: Even if the device is damaged, the original car horn button can still control the original car horn to sound through the normally closed contact of the horn relay terminal actuator. Attached Figure Description

[0031] Figure 1 This is a block diagram of the overall structure of the system of the present invention;

[0032] Figure 2 This is a flowchart of the control logic of the system of the present invention;

[0033] Figure 3 This is a schematic diagram of the electrical connection of the switch execution unit in this invention. Detailed Implementation

[0034] Example 1 (Wireless mode, based on ESP32, first mode)

[0035] The inventors have built a prototype system based on the ESP32 development board and tested it by connecting it to the circuit of a special vehicle.

[0036] Hardware configuration:

[0037] Cab-side: ESP32-WROOM-32 module, connected to the 12V power output of the alarm, equipped with a 1.3-inch OLED display and two control buttons.

[0038] Relay side: ESP32-C3 module (low power), powered by the vehicle's constant 12V power supply stepped down to 3.3V via LDO, controls a single-pole double-throw relay (model: SRD-12VDC-SL-C).

[0039] Electrical connections:

[0040] The common terminal (COM) of the relay is connected to the output wire of the original car horn button.

[0041] The normally closed (NC) contact of the relay is connected to the control terminal of the original vehicle horn relay.

[0042] The normally open contact (NO) of the relay is connected to a GPIO pin of the ESP32-C3 module on the relay side, and then wirelessly connected to the ESP32-WROOM-32 module on the cab side to control the alarm control unit inside the ESP32-WROOM-32 module on the cab side.

[0043] Another GPIO pin of the ESP32 at the driver's cab (as the output of the alarm control unit) is connected to the amplification control terminal of the alarm host.

[0044] Control program logic:

[0045] After the ESP32 in the driver's cab is powered on, it detects the power supply status of the alarm through the first status detection unit. If the power supply is normal, it sends a wake-up broadcast through the ESP-NOW protocol.

[0046] The ESP32 on the relay side is in sleep mode by default (power consumption of about 0.8mA@5V). It is woken up after receiving a wake-up broadcast, and the GPIO is set high to energize the relay coil and switch to the normally open path.

[0047] The ESP32 button status detection unit on the relay side enables GPIO interrupt to listen for the original vehicle horn button signal. When the button is detected to be pressed, a trigger command is sent to the driver's cab via the ESP-NOW protocol.

[0048] After receiving the command, the ESP32 in the driver's cab outputs a 50ms high-level pulse to the loudspeaker control terminal of the alarm host through the alarm control unit, triggering the alarm to play the current sound effect.

[0049] Test results:

[0050] Vehicle testing of the prototype system showed that when the alarm is activated, the original horn button on the steering wheel can be seamlessly switched to the alarm amplification control switch, with a response delay of less than 30 milliseconds and no interference to the original vehicle's CAN bus or horn system. The measured power consumption at the relay terminal in standby mode was 0.6mA@12V, which has no significant impact on the vehicle's battery. This prototype system has verified the feasibility and reliability of the invention.

[0051] Example 2 (Second Mode, Active from the Cab)

[0052] The difference between this embodiment and Embodiment 1 lies in the power supply method and synchronization logic.

[0053] Power supply configuration:

[0054] The ESP32 in the driver's cab is connected to the vehicle's ACC power supply (12V power controlled by the ignition switch) and is powered by its own power management module.

[0055] The ESP32 in the driver's cab is connected to the ESP32 on the relay side via the ESP-NOW protocol. The GPIO of the ESP32 on the relay side controls the alarm host power-on circuit and detects the alarm power-on status, feeding back to the driver's cab.

[0056] Control program logic:

[0057] After the ESP32 in the driver's cab is powered on, a standby interface is displayed on the screen. The user can select to turn it on or off using the control buttons on the user interaction unit.

[0058] When the user presses the power button, a wake-up broadcast is sent to the relay to establish a connection. After the connection is established, the ESP32 in the driver's cab sends a power-on command to the alarm host through the ESP-NOW protocol. After receiving the alarm power-on completion command, the relay is immediately woken up and switched to the normally open path.

[0059] When the user presses the power off button, the ESP32 in the driver's cab sends a power off command to the alarm host and a sleep command to the relay, which then returns to a low-power standby state.

[0060] The ESP32 in the driver's cab monitors the status feedback of the alarm host in real time through the synchronization control unit to ensure that the status of both are synchronized.

[0061] Mode switching:

[0062] Users can freely switch between the first and second modes through the settings menu on the display screen, and the synchronization control unit automatically adjusts the power supply detection logic and synchronization strategy.

[0063] Example 3 (Direct control path from relay terminal)

[0064] The difference between this embodiment and Embodiment 1 lies in the selection of the control path.

[0065] When the special vehicle alarm host is installed in the engine compartment (near the relay end), the normally open contact (NO) of the relay should be directly connected to the amplification control end of the alarm host, rather than to the driver's cab end.

[0066] Control logic:

[0067] When the alarm is activated, the relay is awakened, the switch execution unit operates, and the relay switches to the normally open path.

[0068] The button status detection unit of the ESP32 on the relay side enables GPIO interrupt to listen for the original car horn button signal.

[0069] When a button is detected to be pressed, the ESP32 relay outputs a trigger signal directly to the loudspeaker control terminal of the alarm host through the normally open contact of the switch execution unit, triggering the alarm to play a sound effect.

[0070] Advantages: No need to transmit button signals via wireless communication, resulting in faster response speed (theoretical latency less than 5ms) and reduced reliance on wireless communication.

[0071] Example 4 (Wired backup mode, wired communication is preferred)

[0072] The difference between this embodiment and Embodiment 1 lies in the strategy for selecting the communication method.

[0073] In addition to wireless communication, a CAN bus or single-wire serial communication line is added as a wired communication backup between the ESP32 in the driver's cab and the ESP32 on the relay side. When both are connected via wired communication and powered on, the system prioritizes wired communication for data exchange; when wired communication is unavailable, it automatically switches to wireless communication mode. This mode ensures the system's reliability in the electromagnetic interference-prone environment of modified special vehicles.

[0074] Example 5 (Electronic Switch Scheme)

[0075] The difference between this embodiment and Embodiment 1 is that the switch execution unit uses a MOSFET electronic switch chip (such as TI's TPS22976 or a similar dual-channel load switch) instead of a relay. The two GPIO pins of the ESP32 are connected to the two enable terminals (EN1, EN2) of the electronic switch chip. When the original car horn button is needed to control the original car horn, the first channel is enabled and the second channel is disabled; when the original car horn button is needed to control the alarm, the second channel is enabled and the first channel is disabled. The electronic switch solution has the advantages of no mechanical contacts, fast response speed, and long lifespan.

Claims

1. A special vehicle horn integrated control system, characterized in that, include: The cab-end control device includes a first microcontroller, a first communication module, a first status detection unit, an alarm control unit, and a user interaction unit; The horn relay terminal actuator is connected in parallel or in series with the original horn relay of the special vehicle and is powered by the vehicle's constant power supply. It includes a second microcontroller, a second communication module, a button status detection unit, and a switch execution unit. A synchronization control unit is configured to establish bidirectional state synchronization between the cab-end control device and the special vehicle alarm. The synchronization control unit supports the following two synchronization modes: First mode: When the special vehicle alarm is turned on, the cab-end control device is turned on simultaneously; when the special vehicle alarm is turned off, the cab-end control device is turned off simultaneously. Second mode: When the cab-end control device is turned on, the special vehicle alarm is turned on simultaneously; When the cab-end control device is turned off, the special vehicle alarm is turned off simultaneously. The first status detection unit is used to detect the working status of the special vehicle alarm and generate a corresponding status signal; The button status detection unit is used to monitor the action signal of the original vehicle horn button in real time. The alarm control unit is electrically connected to the special vehicle alarm amplification control terminal and is used to output control signals to control the alarm amplification switch. The switch execution unit includes a relay or electronic switch chip, whose control terminal is electrically connected to the output terminal of the second microcontroller, whose common terminal is connected to the original vehicle horn button signal line, whose normally closed contact is connected to the original vehicle horn control terminal, and whose normally open contact can be selectively connected to the alarm control unit or directly connected to the special vehicle alarm amplification control terminal. When the special vehicle alarm is in the off state (first mode) or the cab-end control device is in the off state (second mode), the horn relay end actuator is in a low-power standby state, the normally closed contact of the switch actuator remains on, and the original vehicle horn button only controls the original vehicle horn. When the special vehicle alarm is in the on state (first mode) or the cab-end control device is in the powered-on state (second mode), the horn relay terminal actuator is activated, the switch actuator unit is activated, the normally closed contact is disconnected and the normally open contact is opened, the button status detection unit listens to the action signal of the original vehicle horn button in real time, and transmits the button signal to the alarm control unit through the second communication module, or directly to the special vehicle alarm amplification control terminal through the normally open contact of the switch actuator unit.

2. The system according to claim 1, characterized in that, The cab-end control device and the horn relay-end actuator establish a communication connection through the first communication module and the second communication module. This communication connection supports both wireless and wired communication.

3. The system according to claim 2, characterized in that, When the cab-end control device and the horn relay-end actuator establish a connection via wired communication and both are powered on, wired communication is preferred for data exchange.

4. The system according to claim 1, characterized in that, Both the first microcontroller and the second microcontroller are microcontrollers with wireless communication capabilities.

5. The system according to claim 1, characterized in that, The switching execution unit uses a relay or MOSFET electronic switching chip.

6. The system according to claim 1, characterized in that, The cab-end control device also includes a display screen for displaying connection status, time, voltage, temperature, fault codes, and extended function information.

7. The system according to claim 1, characterized in that, The user interaction unit includes the display screen and at least one control button. The user can manually control the cab-end control device to turn on or off through the control button, thereby simultaneously controlling the special vehicle alarm.

8. The system according to claim 1, characterized in that, The horn relay terminal actuator is in a low-power standby state when it does not receive a wake-up signal, and its standby power consumption is less than 1 milliwatt.

9. The system according to claim 1, characterized in that, The activation signal of the original vehicle horn button is transmitted through the normally open contact of the switch execution unit, and one of the following two control paths is selected based on the installation location of the special vehicle alarm: Path 1: The signal is transmitted to the alarm control unit, which then controls the loudspeaker switch of the special vehicle alarm. Path 2: Direct transmission to the special vehicle alarm amplification control terminal.

10. A special vehicle, characterized in that, Including the horn integrated control system as described in any one of claims 1-9.

11. A method for integrated control of a horn on a special vehicle, characterized in that, Includes the following steps: Step S1: Configure the synchronization mode, select either the first mode or the second mode; Step S2: When the first mode is selected, check the working status of the special vehicle alarm; When the second mode is selected, the operating status of the cab-side control device is detected. Step S3: When the active side is detected to be in the off state, the cab-end control device is turned off (first mode) or the special vehicle alarm is turned off (second mode), the horn relay end actuator enters the low power standby state, and the original vehicle horn button and the original vehicle horn maintain the circuit; Step S4: When the active side is detected to be in the open state, the cab-end control device is turned on (first mode) or the special vehicle alarm is turned on (second mode), and a wake-up signal is sent to the horn relay end actuator; Step S5: After the horn relay terminal actuator is awakened, the circuit between the original vehicle horn button and the original vehicle horn is cut off, and the control circuit between the original vehicle horn button and the special vehicle alarm amplification switch is established. Step S6: Monitor the original vehicle horn button operation and control the special vehicle alarm amplification switch in real time.

12. The method according to claim 11, characterized in that, It also includes step S7: displaying the system connection status, vehicle voltage, ambient temperature, and fault diagnosis information on the display screen in real time.

13. The method according to claim 11, characterized in that, The method of establishing the control path in step S5 is selected according to the installation location of the special vehicle alarm: when the installation location of the special vehicle alarm is close to the driver's cab, the control device at the driver's cab end receives the button signal and controls the special vehicle alarm; when the installation location of the special vehicle alarm is close to the relay end, the actuator at the horn relay end directly controls the special vehicle alarm.

14. The method according to claim 11, characterized in that, The cab-side control device and the horn relay-side actuator exchange data via wireless or wired communication, with wired communication being preferred.

15. The method according to claim 11, characterized in that, The synchronization mode is set and switched through the user interaction unit of the cab-end control device.

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