WO2009035343A1

WO2009035343A1 - Alarm device

Info

Publication number: WO2009035343A1
Application number: PCT/NZ2008/000230
Authority: WO
Inventors: Allan David Mackay
Original assignee: Allan David Mackay
Priority date: 2007-09-11
Filing date: 2008-09-09
Publication date: 2009-03-19
Also published as: NZ561358A

Abstract

The invention provides an alarm device suitable for use in vehicles to alert a driver when the device detects driver fatigue. The alarm device includes a switch circuit and a control circuit. In one form the switch circuit has one or more switches arranged on a flexible laminate, the laminate including on its surface circuitry connecting the one or more switches. The control circuit in one form is connected to the switch circuit, the control circuit comprising a processor and an alarm means, the processor being arranged to activate the alarm means if the device is in use and all of the switches are in an off-state.

Description

ALARM DEVICE

FIELD OF THE INVENTION

The present invention relates to an alarm device. Specifically, but not exclusively, the present invention relates to an alarm device for use in vehicles to alert the operator of the vehicle (the driver) when the device detects driver fatigue.

BACKGROUND TO THE INVENTION

Driver fatigue is widely recognised as a contributing factor in accidents or crashes relating to vehicles. According to Land Transport New Zealand, driver fatigue was identified as a contributing factor in 134 fatal crashes and 1,703 injury crashes between 2002 and 2004 (approximately 11% of fatal crashes and 6% of injury crashes each year).

While driver fatigue can be avoided by taking precautions, such as stopping and having breaks while driving or sharing the task of driving with others, it can be difficult to remedy driver fatigue once it has set in. The typical symptoms of driver fatigue include tiredness, weariness and exhaustion. When these symptoms set in, a driver may no longer be able to make informed decisions (e.g. stopping for a break) to alleviate driver fatigue. For this reason, some external indicator or alarm should be used to alert a driver of driver fatigue.

One prior art alarm that serves to alert a driver of driver fatigue is described in PCT Publication WO 2006/121996 to Power. The alarm of Power includes pressure sensors that are mounted around a tube for circumferential fitting over a steering wheel. The alarm also includes a control panel that raises an alarm when all of the sensors sense a pressure that is below a predetermined level.

It is an object of the present invention to provide an alarm device that either provides further improvements over the prior art or that at least provides the public with a useful choice. SUMMARY OF THE INVENTION

In a first aspect, the present invention broadly relates to an alarm device comprising: a switch circuit having one or more switches arranged on a flexible laminate, the laminate including on its surface circuitry connecting the one or more switches; and a control circuit connected to the switch circuit, the control circuit comprising a processor and an alarm means, the processor being arranged to activate the alarm means if the device is in use and all of the switches are in an off-state.

Preferably, the one or more switches are staggered along the length of the switch circuit.

Preferably, the flexible laminate is a copper-clad laminate.

In a second aspect, the present invention broadly relates to an alarm device comprising: a switch circuit having one or more switches, the switch circuit being adapted for mounting on a vehicle's steering wheel; and a control circuit connected to the switch circuit and comprising one or more batteries, a main switch, a voltage regulator, a processor and an alarm means, the main switch being arranged to turn the alarm device on and off, the voltage regulator being arranged to direct current from the one or more batteries to the processor only when the main switch is in an on-state and all of the switches in the switch circuit are in an off-state, and the processor being arranged to activate the alarm means.

In a third aspect, the present invention broadly relates to an alarm device comprising: a switch circuit having one or more switches, the switch circuit being adapted for mounting on a vehicle's steering wheel; and a control circuit connected to the switch circuit and comprising a processor and an alarm means, the processor being arranged to: operate on a first frequency, and output signals on a second frequency, which is higher than the first frequency, to activate the alarm means if the device is in use and all of the switches are in an off-state. In a fourth aspect, the present invention broadly relates to an alarm device comprising: a switch circuit having one or more switches, the switch circuit being adapted for mounting on a vehicle's steering wheel; and a control circuit connected to the switch circuit and including a main switch, soft- start circuit, a processor and an alarm means, the soft-start circuit being arranged to prevent excessive current from being drawn by the control circuit when the main switch is turned on, and the processor being arranged to activate the alarm means if main switch is in an on-state and all of the switches in the switch circuit are in an off-state.

The term 'comprising' as used in this specification means 'consisting at least in part of, that is to say when interpreting statements in this specification which include that term, the features, prefaced by that term in each statement, all need to be present but other features can also be present. Related terms such as 'comprise' and 'comprised' are to be interpreted in similar manner.

The term 'alarm means' as used in this specification denotes any form of alerting signal that can be conveyed to a driver to alert the driver of driver fatigue or symptoms of driver fatigue. The alerting signal can be an audio signal, a visual signal, a vibration signal or the like.

In this specification, where reference has been made to patent specifications, other external documents, or other sources of information, this is generally for the purpose of providing a context for discussing the features of the invention. Unless specifically stated otherwise, reference to such external documents or sources of information is not to be construed as an admission that such documents or sources of information in any jurisdiction are prior art, or form part of the common general knowledge in the art. The present invention may also be said broadly to consist in the parts, elements and features referred to or indicated in the specification of the application, individually or collectively, and any or all combinations of any two or more said parts, elements or features. Where specific integers are mentioned herein which have known equivalents in the art to which this invention relates, such known equivalents are deemed to be incorporated herein as if individually set forth.

BRIEF DESCRIPTION OF THE FIGURES

Preferred forms of the device of the present invention will now be described with reference to the accompanying figures in which:

Figure 1 shows a schematic of the preferred form device installed on a steering wheel in one form,

Figure 2 shows a schematic of the switch circuit and control circuit of the device of Figure 1,

Figure 3A shows a circuit diagram of the switch circuit of Figure 2,

Figure 3B shows a plan view of the layout of switches on the switch circuit of Figure 2,

Figure 3C shows the connection paths for the switch layout of Figure 3B,

Figure 4A shows a circuit diagram of the control circuit of Figure 2,

Figure 4B shows a plan view of the layout of components on the control circuit of Figure 2, and

Figure 4C shows the connection paths for the component layout of Figure 4B. DETAILED DESCRIPTION OF THE PREFERRED FORMS

The Preferred Form Device

The preferred form device of the present invention comprises a control circuit and one or more switch circuits. Referring to Figure 1, the device is shown generally as 10, the control circuit is shown as 12 and a switch circuit is shown as 14. Although only one switch circuit 14 is illustrated in Figure 1, in one preferred form, more than one switch circuit 14 is provided. The plurality of switch circuits are preferably positioned at various locations around a vehicle's steering wheel. For instance, switch circuits can be mounted at the 10 o'clock and 2 o'clock positions on the steering wheel. Alternatively or additionally, the switch circuits can be provided at the 4 o'clock and 8 o'clock positions or the 3 o'clock and 9 o'clock positions on the steering wheel. The switch circuits can be positioned at any suitable position around the steering wheel.

It will be appreciated that the switch circuit 14 in one form is encased within a cover. The cover in one form extends entirely around the vehicle steering wheel. In another embodiment the cover extends partially around the vehicle steering wheel. In a further embodiment the cover has sections of the cover that do not conceal the vehicle steering wheel.

Referring to Figure 2, the control circuit 20 of the preferred form device includes a processor 22 and an alarm means 24. The alarm means 24 is preferably a piezoelectric sounder or buzzer.

The control circuit 20 also includes one or more batteries 26. The one or more batteries 26 may be rechargeable or non-rechargeable. Preferably, two coin cell batteries are provided. Although the figure shows the one or more batteries 26 being installed within the boundaries of the control circuit's board, this is not essential. Where necessary or desired, the one or more batteries 26 may be contained within the steering wheel cover and be connected to the control circuit. In use, the control circuit 20 is connected (either wired or wireless) to one or more switch circuits 28. Each switch circuit 28 includes one or more switches 29. The switch circuit 28 is designed such that the switches 29 work in parallel. If any one of the switches 29 is closed, the alarm means 24 is inactive. That is to say, if the driver is gripping the steering wheel with sufficient force, the alarm means 24 should not be activated. If all switches 29 are released (i.e. where the driver is no longer gripping the steering wheel with sufficient force), the alarm means 24 is activated.

The number of switches 29 used on each switch circuit 28 (or the number and placement of the switch circuits 28 themselves) may be varied to suit the desired sensitivity of the device. Also, the positioning of the switches 29 within the switch circuit 28 may also be changed to suit where, on the steering wheel, the circuit will be placed, or to allow various combination of switch patterns to be configured. For instance, where switches are staggered as shown in Figure 2, the alarm means 24 may be activated if two neighbouring switches are not closed. Further, the actuating force of the switches and the surface area of the switch contact may be varied. This provides the preferred form device with in-built adjustability.

The switch circuit 28 is preferably based on a printed circuit board that is manufactured from a flexible laminate, which would allow the switch circuit 28 to follow the contours of a steering wheel. The flexible laminate is preferably a copper-dad laminate.

Switch circuit 28 is preferably arranged to be mounted on the exterior of a steering wheel. In one preferred form the device is portable and is removably mounted to a vehicle steering wheel. In another form the device is integrated within a vehicle. In an integrated form the switch circuit is mounted within the steering wheel so that individual switch circuits extend from the steering wheel. Control circuit 20 is mounted internally within the vehicle in the same manner as other vehicle components.

The Preferred Form Switch Circuit

Referring now to Figure 3A, a preferred form circuit diagram is shown for the switch circuit. Eight switches SWl -SW8 are preferably connected in parallel on the circuit. If any one of the switches are closed, the circuit as a whole will be closed, disabling the alarm means.

Figures 3B and 3C show a plan layout and connection paths of the switches respectively. Skilled persons will, of course, appreciate that the layout and connection paths as shown are not essential and can be changed easily.

The Preferred Form Control Circuit

A preferred form circuit diagram for the control circuit will now be described with reference to Figure 4A. An example layout and connection path of the control circuit will also be described with reference to Figures 4B and 4C. As with the switch circuit, skilled persons will appreciate that it is not essential to design the control circuit exactly as shown. The figure has been provided to show one example way in which to form the control circuit; skilled persons will appreciate that various modifications or additions may be made to the example circuit shown without departing from the scope of the present invention.

The preferred form control circuit is arranged to connect to the one or more switch circuits via four junctions Jl -J4. Two junctions are preferably used to connect to one switch circuit. In Figure 4A, it can be seen that junctions Jl and J4 are used to connect to one switch circuit, while junctions J2 and J3 are grounded and disabled. Of course if more connections are needed, more junctions could be provided.

The preferred form control circuit will be further described below in four separate parts: the power supply, the processor, the power supply boost circuit, and the sounder output stage.

The Power Supply

The power supply circuit preferably includes two coin cell batteries, BTl and BT2. Each battery puts out 3 volts, which brings the total voltage of the device to 6 volts. The power supply circuit also includes a main switch Sl that allows the control circuit to be completely turned off to conserve battery life. In the preferred form, the main switch Sl is a miniature slide switch that can be purchased from ITT Industries (Part Number DS10201 IMAQN, Farnell Part Number 443-6313).

There is also a voltage regulator Ul that is preferably a low drop-out, high-efficiency device having a switch-off pin. In the preferred form, the regulator Ul is a 3.3V fixed regulator that is manufactured by National (Part Number LP2981IM5-3.3, Farnell Part Number 956- 144). The regulator Ul is held in an off-state when any one of the switches in the switch circuit is pressed or closed. In this arrangement, the control circuit is in a low-current inactive state, where current consumption by the control circuit is minimised until all switches in the switch circuit is released or opened and the alarm means is activated.

Once the regulator Ul enters an on-state (as a result of all switches being released), the remainder of the control circuit, including the processor U2, is powered. The regulator Ul is then held in the on-state by the processor U2. This allows for a minimum alarm duration to be set and controlled by the processor U2. If a rninirnurn alarm duration is set, and that duration elapses, the processor U2 is arranged to turn off the regulator Ul, returning the circuit into the low-current inactive state.

The Processor

The processor U2 of the control circuit is preferably a low-cost device. In the preferred form illustrated, the processor U2 is a microcontroller manufactured by Microchip Technology, Inc (Part Number PIC16C54C-04/SO).

The processor U2 is arranged to control the alarm means, which is preferably a sounder Pl. In particular, the processor U2 can be used to control one or more of the duration, frequency, pitch and on-off ratio of the sounder Pl. In addition, the processor U2 monitors the switch circuit to determine when any of the switches are pressed.

To ensure the control circuit uses minimal power, the processor U2 receives its power from the regulator Ul. To further reduce power consumption, the processor U2 is adapted so that its clock operates at the lowest frequency achievable, while maintaining the output frequency at the correct resonant frequency to produce maximum sound output from the sounder Pl. The additional benefit of this arrangement is that different sounders with different frequency characteristics may be used without changing the design of the processor U2.

The Power Supply Boost Stage

Where the alarm means is audio-based, such as using sounder Pl, it is preferable for the output volume of the alarm to be reasonably high. To achieve an acceptable sound output volume using the sounder Pl, the drive requirements for the sounder should be met.

In the preferred form, the sounder Pl is a piezoelectric sounder manufactured by Kingstate Electronics Corp. (Part Number KPEl 65, Farnell Part Number 926-978). The preferred form sounder Pl requires 30 volts to achieve a sound pressure level of 85dBA at 10 centimetres. This voltage is created using a boost regulator U4, which is powered directly from the one or more batteries via the main switch Sl. In the preferred form, the boost regulator U4 is a switching regulator manufactured by Linear Technology Corp (Part Number LT3467AES6). Referring to Figure 4A, the required output voltage for the boost regulator U4 is set via resistors R7 (470k, 0.125w, 5%, manufactured by Phycomp, Farnell Part Number 923-4330) and R8 (20k, 0.125w, 1%, manufactured by Multicomp, Farnell Part Number 321-8211).

The preferred form control circuit also includes a soft-start circuit in the form of resistor RlO (preferably 4k7, 0.125w, 5%, manufactured by Phycomp, Farnell Part Number 923- 4098) and transistor T2 (preferably an NPN transistor manufactured by Philips, Part Number BC817-16, Farnell Part Number 873-4739). The purpose of the soft-start circuit is to prevent excessive current from being drawn by the boost regulator U4 on power-up, and collapsing the battery voltage. Other suitable forms of a soft-start circuit will be apparent to skilled persons. The Sounder Output Stage

As noted earlier, where a sounder is used, the output frequency, pitch and on-off ratio of the sounder is preferably determined by the processor U2. Therefore, on one side of the sounder Pl, a low-voltage output of the processor U2 is switched using transistor Tl

(preferably having die same specifications as noted for T2 earlier). The other side of the sounder Pl is supplied with the 30 volts derived from the power supply boost stage.

A list of the components used in the preferred form circuit shown in Figure 4A is noted below for completeness. It should be noted that the components and the specified values, part numbers and the like are only preferred components and values. It is believed that the present invention has been described completely enough for any skilled person to design a different control circuit or switch circuit for the device of the present invention.

The foregoing describes the invention including preferred forms thereof. Alterations and modifications as will be obvious to those skilled in the art are intended to be incorporated within the scope hereof, as defined by the accompanying claims.

Claims

CLAIMS:

1. An alarm device comprising: a switch circuit having one or more switches arranged on a flexible laminate, the laminate including on its surface circuitry connecting the one or more switches; and a control circuit connected to the switch circuit, the control circuit comprising a processor and an alarm means, the processor being arranged to activate the alarm means if the device is in use and all of the switches are in an off-state.

2. The alarm device of claim 1 wherein the one or more switches are staggered along the length of the switch circuit.

3. The alarm device of claim 1 or claim 2 wherein the flexible laminate is a copper- clad laminate.

4. An alarm device comprising: a switch circuit having one or more switches, the switch circuit being adapted for mounting on a vehicle's steering wheel; and a control circuit connected to the switch circuit and comprising one or more batteries, a main switch, a voltage regulator, a processor and an alarm means, the main switch being arranged to turn the alarm device on and off, the voltage regulator being arranged to direct current from the one or more batteries to the processor only when the main switch is in an on-state and all of the switches in the switch circuit are in an off-state, and the processor being arranged to activate the alarm means.

5. An alarm device comprising: a switch circuit having one or more switches, the switch circuit being adapted for mounting on a vehicle's steering wheel; and a control circuit connected to the switch circuit and comprising a processor and an alarm means, the processor being arranged to: operate on a Erst frequency, and output signals on a second frequency, which is higher than the first frequency, to activate the alarm means if the device is in use and all of the switches are in an off-state.

6. An alarm device comprising: a switch circuit having one or more switches, the switch circuit being adapted for mounting on a vehicle's steering wheel; and a control circuit connected to the switch circuit and including a main switch, soft- start circuit, a processor and an alarm means, the soft-start circuit being arranged to prevent excessive current from being drawn by the control circuit when the main switch is turned on, and the processor being arranged to activate the alarm means if main switch is in an on-state and all of the switches in the switch circuit are in an off-state.