Abstract:
A method and system for indicating a status of a load of a sub-system in a marine vehicle where the load is controlled by a switch provided on a steering wheel of the marine vehicle. The method comprises: providing a switch controller in the steering wheel for controlling communications between the steering wheel and the marine vehicle; providing a switch for the load on the steering wheel; providing a status indicator for the load on the steering wheel; detecting an activation of the switch by the switch controller; the switch controller transmitting a command to the load in the marine vehicle in response to the activation; providing a load controller in the marine vehicle, the load controller controlling a power input to the switch controller, the load controller receiving the command and activating the load in response to the command; detecting a status of the load; interrupting a power input to the switch controller for a predetermined interruption duration corresponding to the detected status; the switch controller activating the status indicator to indicate the detected status of the load.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     The present application claims priority of U.S. provisional patent application No. 60/546,944 filed on Feb. 24, 2004 by Applicant entitled COMMUNICATION WITH A STEERING WHEEL SWITCH and is related to co-pending U.S. patent application Ser. No. 10/961,297 filed on Oct. 12, 2004 by Applicant, entitled MARINE VEHICLE STEERING WHEEL SWITCH POWERING, to co-pending U.S. patent application Ser. No. 10/961,224 filed on Oct. 12, 2004 by Applicant, entitled STATUS LIGHT FOR SWITCH ON BOAT STEERING WHEEL and to co-pending provisional U.S. patent application Ser. No. 10/961,227 filed on Oct. 12, 2004 by Applicant entitled FUEL LEVEL VARIATION DETECTOR FOR MARINE VEHICLE, all of which are incorporated herewith by reference. 
    
    
     FIELD OF THE INVENTION 
     The invention relates to switches and indicators made available on steering wheels of marine vehicles, such as speed boats. More specifically, it relates to a communication method and system enabling data exchange between the steering wheel and the marine vehicle. 
     BACKGROUND OF THE INVENTION 
     Prior art systems provide lights on switches which are lit when the switch has been activated. Such systems allow a user to be sure that the switch has been activated, i.e. they confirm that the command was requested. These switches are provided on the dashboard of marine vehicles. 
     These prior art systems do not enable communication between the marine vehicle and its steering wheel nor do they allow to confirm the actual status of a subsystem subsequently to the request of the command. 
     SUMMARY OF THE INVENTION 
     Accordingly, an object of the present invention is to provide an indication that the sub-system controlled by a switch is executing the command as requested by enabling communication between the marine vehicle and its steering wheel. 
     According to a first broad aspect of the present invention, there is provided a method for indicating a status of a load of a sub-system in a marine vehicle where the load is controlled by a switch provided on a steering wheel of the marine vehicle. The method comprises: providing a switch controller in the steering wheel for controlling communications between the steering wheel and the marine vehicle; providing a switch for the load on the steering wheel; providing a status indicator for the load on the steering wheel; detecting an activation of the switch by the switch controller; the switch controller transmitting a command to the load in the marine vehicle in response to the activation; providing a load controller in the marine vehicle, the load controller controlling a power input to the switch controller, the load controller receiving the command and activating the load in response to the command; detecting a status of the load; interrupting a power input to the switch controller for a predetermined interruption duration corresponding to the detected status; the switch controller activating the status indicator to indicate the detected status of the load. 
     According to another broad aspect of the present invention, there is provided a system for indicating a status of a load of a sub-system in a marine vehicle, the load being controlled by a switch provided on a steering wheel of the marine vehicle. The system comprises: a switch controller in said steering wheel for controlling communications between said steering wheel and said marine vehicle; a switch for activating a load of said sub-system, located on said steering wheel; a status indicator for said load, on said steering wheel; a switch detector for detecting an activation of said switch; a transmitter for transmitting a command corresponding to said switch activation to said load, in said marine vehicle, in response to said switch detector; a load controller in said marine vehicle, said load controller controlling a power input to said switch controller, said load controller receiving said command and activating said load in response to said command; a status detector for detecting a status of said load; a power interrupter for interrupting a power input to said switch controller for a predetermined interruption duration corresponding to said detected status; wherein said switch controller activates said status indicator to indicate said detected status of said load. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       These and other features, aspects and advantages of the present invention will become better understood with regard to the following description and accompanying drawings wherein: 
         FIG. 1  is a block diagram of a system for indicating a status in accordance with an embodiment of the invention, illustrating the main components; 
         FIG. 2  is a cross-sectional view of the system for indicating a status in accordance with an embodiment of the invention, where the components are illustrated inside a steering wheel and hub assembly; 
         FIG. 3  is an exploded view of the system for indicating a status of  FIG. 2 ; 
         FIG. 4  is a front elevation view of a steering wheel in accordance with an embodiment of the invention, illustrating switches and status indicators; 
         FIG. 5  is a flow chart of the main steps of the energy management method used in accordance with an embodiment of present invention; 
         FIG. 6  is a flow chart of the steps of a method carried out by the elements provided in the steering wheel, in accordance with an embodiment of the present invention; 
         FIG. 7  is a flow chart of the steps of the method carried out by the elements provided in the marine vehicle, in accordance with an embodiment of the present invention; and 
         FIG. 8  is a timing chart of exemplary communications between the steering wheel the marine vehicle in accordance with preferred embodiments of the system and method of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     In the description of the present invention, it will be assumed that the energy provided in the steering wheel is managed by a power management system and that having sufficient energy to operate the system described and carry out the steps of the method described is not an object. 
     With reference to  FIGS. 1 ,  2  and  3 , a preferred embodiment of the present invention will be explained in detail. A steering wheel  322  is rotatably mounted onto the hub of the marine vehicle, within the hub bellow  300 . When the ignition key  100  is turned on, the 12 volt battery (not shown) of the boat is connected to an electrical circuit board  302  provided in the hub of the marine vehicle by the power management system  104 . When the electrical circuit board  302  is powered on, it first generates, using a load controller  106 , a waveform which will drive the primary  108  of a contactless rotary transformer through power transistors  110 . The rotary transformer has a first ring shaped magnet core  308  with the primary coil  310  fixed onto the stator and a second ring shaped magnet core  308  with the secondary coil  312  fixed onto the steering wheel  322  via the rotor. The stator is located in the hub and the rotor is provided in the steering wheel. There is an air gap between the two coils making them entirely contactless. A soft magnetic material is used for these cores to make the magnetic resistance appearing in the magnetic circuit of the two coils small enough so that an AC electric energy impressed on the primary coil  108  is induced to the secondary coil  112  instantaneously. This excitation of the primary  108  will induce energy on the secondary  112  of the contactless rotary transformer. This electrical energy can be used to power the switch controller  114  of the steering wheel. 
     The switch controller  114  reads the electrical signals from switches  120 . The switches  120  are provided on the steering wheel and can be used to control a plurality of subsystems of the marine vehicle, such as the lights, the horn, the ventilation fan, the windshield wiper and washer, the bilge pump and blower, the emergency start, the anchor, the hazard warning, the radio, etc. The switches can be provided on a keypad that is affixed to the steering wheel. This keypad should be weather resistant if the steering wheel is not protected from the weather. The switches will typically bear pictograms or logos representing the sub-system that they control. They can also bear the name of the sub-system. Switch standards exist for marine vehicles and should be used when appropriate. An example of switch disposition on a steering wheel is illustrated in  FIG. 4 . 
     The switch controller  114  transmits a data train, created by a data driver  124 , via infrared (IR) transmission using an IR emitting diode  126 . The data train identifies which switch or switches are activated in the steering wheel and therefore contains the commands to which subsystem or subsystems must be activated. The data train is captured by a phototransistor  128 , is received by a signal receiver  130  and is sent to the load controller  106  for communication with the proper subsystem of the boat through an output interface  134 . More specifically, the interface  134  communicates the command via which a load of the subsystem is activated. 
     The output interface  134  has as many outputs as there are switches  120  on the steering wheel. Output interface  134  can have steady state switches or electromechanical relays. It is possible to use the output interface  134  to communicate on a data network of the boat, in which case it comprises a multiplexer. The National Marine Electronics Association has introduced the NMEA 2000 interface standard. The standard contains the requirements of a serial data communications network to inter-connect marine electronic equipment on vessels. It is multi-master and self configuring, and there is no central network controller. Equipment designed to this standard have the ability to share data, including commands and status with other compatible equipment over a single channel. If the output interface  134  is compliant with the NMEA 2000 standard, it can allow communication between the switches  120  and the subsystems of the network. 
     Oppositely, inputs of an input interface  132  transmit status signals from the different loads to the switch controller  114  via the load controller  106 , using the method described below. The preferred load and switch controllers are microprocessors. 
     Preferably, the solid state switches  306 , the infrared receivers  304  and the load controller are provided on a first printed circuit board  302  which is fixed to the stator portion of the steering wheel/hub assembly. A second printed circuit board is provided within the rotor portion (the steering wheel) and includes the infrared emitter  316  and the switch controller  318 . 
     When the ignition key  100  is turned off, the load controller  106  ceases to generate a waveform and to drive the primary  108  of the transformer. Activation of the switches does not trigger any processing thereafter unless a power management system is provided which ensures that the switches, the switch controller and the emitter are maintained in a powered state regardless of the position of the ignition key. Such a power management system is described in co-pending U.S. patent application Ser. No. 10/961,297 filed on Oct. 12, 2004 by Applicant, entitled MARINE VEHICLE STEERING WHEEL SWITCH POWERING. 
     Preferably, the switches are provided on the steering wheel  322  and are combined with a status indicator  136  which indicates a status of the load of the sub-system that they control. Typically, the status indicator is a visual indicator, preferably a LED, which is lit when the corresponding sub-system is functioning normally. If the status led is unlit, the subsystem is inactive. Optionally, if the switch has been pressed but the corresponding sub-system is not responding or cannot execute the command, the status led can start flashing to indicate an error, and the malfunction thereof. 
       FIG. 4  shows the steering wheel  322 , switches  324 , and visual indicators. Three types of switches are illustrated. The first type has a simple light button  700  which is lit or flashes when the status of the sub-system is confirmed. It can also be lit when the button is first pressed. The second type has a simple button surrounded by a ring that is backlit and has a status led  704  which is lit or flashes when the status of the sub-system is confirmed. The third type  706  is a combination of the two. The light ring is backlit and the button is lit or flashes depending on the status of the sub-system. Other combinations of backlighting, switches and leds could be used to highlight the actual status of a corresponding sub-system. 
     With reference to  FIG. 5 , the main steps of the energy management will now be described. The energy management process is started  200 . A verification is made as to whether the ignition key is turned on  202 . If it is, the primary of the transformer is excited  204 . Tension is then present at the secondary of the transformer  206 . The steering wheel is then powered up  208 . The process loops back to checking whether the ignition key is turned on  202 . If the ignition key is not turned on  202 , the primary of the transformer is not excited  212 . There is therefore no tension present at the secondary of the transformer  214 . The process loops back to checking whether the ignition key is turned on  202 . 
     With reference to  FIG. 6 , the main steps carried out by the elements in the steering wheel will now be described. The status led on steering switches method starts  500 . The steering switches are scanned by the switch controller  114  to verify if they have been activated  502 . Depending on whether the switch was activated  504 , the switch controller  114  either continues to scan the steering switches for activation  502  until a switch is activated or the switch controller  114  transmits a IR message corresponding to that switch command  506  from the steering wheel to the hub/dash using the IR circuitry discussed above. It further transmits a load status request to the hub/dash  507 . The switch controller  114  starts a time counter A  508 . It monitors the induced energy of the power input. If the power inputted is down  510 , this constitutes a logical zero. If it is on, that is there is power being inputted to the processor, it constitutes a logical one. Therefore, as long as there is power inputted to the switch controller, the counter counts the number of seconds elapsed  512 . Counter A is used to ensure that in case there is no interruption in the induced energy in a predetermined period of time, the process will stop monitoring the induced energy and will return to verifying the state of the switches. Preferably, the maximum waiting time for counter A is 10 milliseconds. Once it has counted up to this pre-set threshold value, it goes back to monitoring the switches. Therefore, time counter A may be referred to as being a status timer. 
     If the power input is detected to be down, a time counter B is started  514 . A second check as to the power input is made  516 . If the power is still down, the process loops back to monitoring the power. If the power input becomes on, the counter B is stopped  518 . If the value of the counter B  520  is small, the status light for the activated switch is turned off  522 . If the value is medium, the status light for the activated switch is turned on  524 . If the value is large, the status light for the activated switch is blinked  526 . Preferably, a short interruption lasts 3 milliseconds, a medium interruption lasts 6 milliseconds and a long interruption lasts 9 milliseconds. Preferably, counter B counts in multiples of 3 milliseconds. The process then continues for the next switch  528 . Finally, the process loops back to reading the status of all switches. Therefore, time counter B may be referred to as being an interruption timer. 
     With reference to  FIG. 7 , the main steps carried out by the elements in the hub/dash will now be described. At initialization, all loads are turned off  600 . A time counter C is started  602 . The load controller  106  checks whether a switch command is received from the steering wheel  604 . If there is no incoming message, the processor continues to wait for a message until a predetermined threshold wait period has elapsed  606 . Preferably, this threshold wait period is a few seconds. It is only a safety check in case communication with the steering wheel is lost. Obviously, if numerous switches are provided on the steering wheel and checking their status takes more than a few seconds, the delay for turning off all loads will have to be increased. When it has elapsed, all loads are turned off  600  and the counter is reset  602 . If a switch command is received by the load controller  106 , the load controller verifies the type of message  608 . If it is a command, the load controller  106  instructs the proper load on the boat to execute it  620 . The load controller  106  then starts the time counter  602  and the verification for the reception of the IR message  604  starts again. Therefore, time counter C may be referred to as being a failure timer. 
     If the message type is a status request for a particular load, the load controller  106  verifies if the load is activated  610 . If it is activated, the load controller  106  sends a medium pulse power interruption to the steering wheel to signify that the load is activated  618 . If the load is not activated, a check is made as to whether the load is really not activated or simply not accessible or responsive  612 . If the load really is not activated, a short pulse power interruption is sent to the steering wheel to signify that the load is not activated  614 . Finally, if a confirmation that the load is not activated cannot be obtained, a long pulse power interruption is sent to the steering wheel to signify that the load is defective  616 . The counter is then started again  602 . 
     Therefore, the present invention provides a way to communicate information about the status of the loads controlled by the switches on the steering wheel without involving wires or another wireless transmission. The information is carried by the powering of the steering wheel, depending on the length of the power interruption. 
       FIG. 8  is a timing chart of the communication between the steering wheel processor and the dashboard hub processor. The events timeline lists the three example events which affect the power input to the steering wheel, thereby communicating status information from the marine vehicle to the steering wheel. The first event is the turning on of the #2 switch. The second event is a defect in load #3. The last event is the turning off of the #2 switch. The steering wheel transmits a plurality of messages to the hub as illustrated. The switch controller repeats the following steps: transmitting the switch activation information; requesting the status for load # i; and monitoring the power input from the marine vehicle to the steering wheel. However, at each repeat, i is incremented by one, so that it first monitors load #1, then load #2, then load #3, etc, until it reaches the last load which may be referred to as load #n; i is then reset to 1, and so forth. The power transferred from hub to steering time line represents the power input to the steering wheel. There are three power interruptions: a short one upon detection that load #1 is not activated, a medium one upon detection that load #2 is activated (following the load command) and a long one upon detection that load #3 is defective. Preferably, the interruption length ratios are referred to as: short: P/3, medium: 2P/3 and long: P. 
     The Status light #2 timeline indicates the state of the status light. A low signal means will turn the light off, and a high signal will turn the light on. Once the power interruption to the steering wheel has communicated that the load #2 is activated, the led for switch #2 is turned on. 
     As soon as the steering wheel transmits a message to the vehicle to activate load #2, the load #2 is turned on. Similarly, when the message is received that the load #2 should be de-activated, the load #2 is turned off. 
     Following detection that load #3 is defective and transmission of that information to the steering wheel by a long interruption of the power input to the steering wheel, the led #3 is made to blink until the problem is resolved. 
     Status indicator  1  is turned off all along, since the corresponding load is not activated. 
     It will be readily understood by a person skilled in the art that a status of some sub-systems of the boat is apparent to an operator of the boat. For example, if the radio switch is pressed on and the music does not begin, the operator will know right away that there is a problem with the radio sub-system. However, for certain sub-systems, the operator has no quick and safe way of determining the status and will benefit from such an indication of the status directly on the steering wheel. 
     As will be understood, the visual indication of the status of the sub-system could be replaced or complemented by a sound indication, especially in the case of vital sub-systems. 
     It will be understood that numerous modifications thereto will appear to those skilled in the art. Accordingly, the above description and accompanying drawings should be taken as illustrative of the invention and not in a limiting sense. It will further be understood that it is intended to cover any variations, uses, or adaptations of the invention following, in general, the principles of the invention and including such departures from the present disclosure as come within known or customary practice within the art to which the invention pertains and as may be applied to the essential features herein before set forth, and as follows in the scope of the appended claims.