BACKGROUND

The present invention relates to a timing system and a method of operating such timing system. More specifically, the present invention relates to a timing system that uses: a parametric speaker that emits modulated ultrasonic waves; and a smart communication device microphone to receive a corresponding lower frequency demodulated wave.

Timing systems that use sound or ultrasonic waves to start or stop a timer are known. For instance, US2009/0213700 “Automated interval timing method devices and system” describes a timing system that uses:

(i) sound received from a start gun; and

(ii) a narrow beam of ultrasonic sound emitted by ultrasonic speakers across a track, to start / stop a timer (or determine interval timing) on a device (with microphone) worn by a user. Similar systems are described in US5, 511 ,045 “Time measurement apparatus and system having reception or transmission function” and US5,737,280 “Clocking system for measuring running speeds of track runners”.

A drawback of known timing systems using ultrasound is that a device capable of picking up ultrasound must be provided to each user. The cost and impracticality of this inhibits mass adoption of such timing systems. It is an object of the present invention to address this drawback and to provide a timing system that: uses emitted ultrasound with a frequency above 30 KHz (typically 40 KHz); and a smart communication device with a microphone that only picks up waves with a frequency 25 KHz and below.

SUMMARY OF THE INVENTION

According to a preferred embodiment of a first aspect of the invention, there is provided a timing system that includes: a first parametric speaker that emits modulated ultrasonic waves with a frequency of at least 30 KHz; and a smart communication device having: a microphone that picks up waves having a frequency of not more than 25 KHz; and a timer that uses waves picked up by the microphone to determine timing, such that, in use, when an object with which the smart communication device is associated passes through the modulated ultrasonic waves emitted by the parametric speaker, the modulated ultrasonic waves are demodulated by interference into lower frequency waves that are picked up by the smart communication device microphone and used by the timer to determine timing.

Typically the first parametric speaker emits modulated waves with a frequency between 30 KHz and 100 KHz.

Generally, the modulated waves emitted by the first parametric speaker comprise: (i) a carrier wave; and (ii) a modulating wave.

Preferably, the modulating wave includes encoded data that, following demodulation, is used by the timer to determine timing.

Typically, the encoded data is selected from one or more of: real time source data; first parametric speaker unique identifier; and status information.

Generally, the first parametric speaker directs a beam of modulated ultrasonic waves along a virtual line across a track.

Preferably, emission of modulated ultrasonic waves by the first parametric speaker is regulated by a sensor that senses the proximity of the object to the virtual line.

Typically, the sensor is selected from one of: a photocell, a laser, an ultrasonic detector; a start gate; and a contact switch.

Optionally, the timing system further includes a second parametric speaker that emits modulated ultrasonic waves with a frequency of at least 30 KHz, which second parametric speaker: (i) emits a wider beam of ultrasonic waves than the first parametric speaker; (ii) is spaced from the first parametric speaker; or (ii) emits a beam of ultrasonic waves that is angularly offset relative to the beam of ultrasonic waves emitted by the first parametric speaker.

According to a second aspect of the invention, there is provided a method of operating a timing system, which method includes the steps of: emitting modulated ultrasonic waves with a frequency of at least 30 KHz via a first parametric speaker; passing an object through the modulated ultrasonic waves emitted by the first parametric speaker to cause the modulated ultrasonic waves to demodulate by parametric interference into lower frequency waves; picking up the lower frequency demodulated waves via a microphone on a smart communication device that is carried on or by the object, which microphone does not pick up waves with a frequency more than 25 KHz; and using the lower frequency demodulated waves picked up by the smart communication device microphone to determine timing.

Typically, the modulated waves emitted by the first parametric speaker have a frequency between 30 KHz and 100 KHz.

Generally, the modulated waves emitted by the first parametric speaker comprise: (i) a carrier wave; and (ii) a modulating wave.

Preferably, the modulating wave includes encoded data that, following demodulation, is used by a timer on the smart communication device to determine timing.

Typically, the encoded data is selected from one or more of: real time source data; first parametric speaker unique identifier; and status information.

Generally, the beam of modulated ultrasonic waves emitted by the first parametric speaker is directed along a virtual line across a track. Preferably, the method further includes the step of sensing the proximity of the object to the virtual line, and consequently to cause the first parametric speaker to emit modulated ultrasonic waves.

Typically, the method further includes the step of emitting modulated ultrasonic waves with a frequency of at least 30 KHz via a second parametric speaker, which modulated ultrasonic waves emitted by the second parametric speaker is: wider than; spaced from; or angularly offset relative to, the modulated ultrasonic waves emitted by the first parametric speaker.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be described in more detail, by way of example only, with reference to the accompanying drawing in which:

Figure 1 is a perspective view of a timing system according to a preferred embodiment of the invention.

DESCRIPTION OF THE INVENTION

With reference to Figure 1 , according to a first aspect of the invention a timing system 10 includes a first parametric speaker 12 and a smart communication device 14. The timing system 10 may be used to time objects 16 (e.g. runners, cyclists, race cars, etc.) traveling along a track 18.

In this specification, references to a smart communication device are intended to include consumer mobile smart devices primarily intended for voice communication (e.g. mobile telephones and Apple watches). The first parametric speaker 12 contains an array of piezoelectric transducers that produce / emit modulated ultrasonic waves 20 with a frequency of at least 30 KHz, preferably between 30 KHz and 100 KHz, and more preferably 40 KHz. The modulated ultrasonic waves 20 comprise:

(i) a carrier wave (i.e. a steady reference tone); and

(ii) a modulating wave (i.e. a wave with a fluctuating frequency).

Preferably, the modulating wave includes encoded data (e.g. real time source data; first parametric speaker unique identifier; status information).

Various techniques may be used to add encoded data to the modulating wave, e.g. DTMF (Dual Tone Multi Frequency), ASK (Amplitude Shift Keying), FSK (Frequency Shift Keying), PSK (Phase Shift Keying) and GSFK (Gaussian Frequency Shift Keying). Typically, multiple tones/frequencies are inputted to the parametric speaker 12 at the same time to improve data stability and reduce interference.

The modulated ultrasonic waves 20 are emitted by the first parametric speaker 12 as a narrow beam (otherwise referred to as a tightly focussed column) of modulated ultrasonic waves. Since the modulated ultrasonic waves 20 are of sufficiently high frequency (in this instance, more than 30 KHz), the low diffraction of these waves enables this narrow beam to be maintained over a reasonable distance required for timing purposes.

It will be appreciated that, when the modulated ultrasonic waves 20 strike an object 16, the carrier wave interferes with the modulating wave, and the resultant parametric interaction demodulates the modulated ultrasonic waves 20 to produce a resultant wave that retains the encoded data. This demodulated wave has a lower frequency than the modulated ultrasonic wave 20. More specifically, the frequency of the demodulated wave is the difference in frequencies between the carrier wave and the modulating wave. In this specification, the demodulated wave has a frequency not greater than 25 KHz.

The smart communication device 14 is a standard off-the-shelf smart communication device with a processor (not shown) and a microphone (not shown, but being the standard microphone on a smart communication device for picking up voice). Smart communication devices 14 typically only “pick up” (i.e. recognise / record) waves with a frequency 25 KHz or less - either the microphone fails to detect frequencies greater than 25 KHz; or the smart communication device 14 processor filters frequencies greater than 25 KHz from waves received by the microphone. One of the reasons that smart communication devices 14 do not register wave frequencies greater than 25 KHz is to eliminate “background noise” / “white noise”. In this specification, the phrase “a microphone that picks up waves having a frequency of not more than 25 KHz” is meant to mean that either:

(i) the microphone is unable to receive waves with frequencies greater than 25 KHz; or

(ii) the microphone is able to receive waves with frequencies greater than 25 KHz, but that the smart communication device 14 processor filters out waves with frequencies greater than 25 KHz.

The smart communication device 14 also includes a timer, in the sense that the smart communication device is able to determine timing (i.e. the lapse of time). It will be appreciated that the timer could comprise any of a variety of functions, features or methods for determining the lapse of time, including, without limitation:

(i) a clock on the smart communication device that starts / stops / sets split times based on demodulated waves picked up by the microphone;

(ii) a processor on the smart communication device that receives:

(a) a first “time stamp” from encoded data picked up by the microphone from demodulated waves; and

(b) a second “time stamp” from encoded data picked up by the microphone from subsequently emitted demodulated waves, and calculates the lapse of time by “subtracting” the first time stamp from the second time stamp. It will be appreciated that “subtracting” is not intended to be limited to simple subtraction, but could include application of a formula.

In essence, the timer on the smart communication device 14 determines timing from demodulated waves picked up by the smart communication device’s 14 microphone.

It will be appreciated that although the encoded data picked up by the microphone from the demodulated waves may be used to determine timing, the encoded data may also be used for other purposes. For example, the encoded data may communicate to the smart communication device 14: real time source data (e.g. GPS receiver for maintaining accurate time sources); positioning data; the unique identifier of the first parametric speaker 12; status information (e.g. battery level, object detection count determined by the sensor 22, temperature, diagnostic information or data from separately connected sensors); the lap of a multi-lap race the object 16 is on; the current weather conditions; the position of the object 16 relative to other objects in the race, etc.

An app downloaded on the smart communication device 14 may enable the smart communication device to process encoded data picked up by the microphone from the demodulated waves for a variety of purposes and display this data, as required. Furthermore, the smart communication device 14 could use its transmitter to transmit data generated from encoded data to remote devices or databases.

Typically, the first parametric speaker 12 is arranged to direct a beam of modulated ultrasonic waves 20 along a virtual line (e.g. a finish line) across a track 18. Although the parametric speaker 12 has been described as being positioned on the side of a track 18, it will be appreciated that the first parametric speaker 12 could alternatively be positioned above the track 18, directed downwards towards the finish line on the track.

To reduce power consumption of the first parametric speaker 12, a sensor 22 may be associated with the first parametric speaker 12. Preferably, the sensor 22 is in wireless communication with the first parametric speaker 12, and is selected from one of: a photocell, a laser, an ultrasonic detector; a start gate; and a contact switch. More preferably, the sensor 22 is incorporated into the first parametric speaker 12 housing. In use, the sensor 22 regulates emission of modulated ultrasonic waves 20 by the first parametric speaker 12 by causing the first parametric speaker 12 only to emit modulated ultrasonic waves 20 when the sensor 22 senses proximity of an object 16 to the virtual line (along which the beam of modulated ultrasonic waves 20 are directed when emitted by the first parametric speaker 12).

Optionally, the timing system 10 may include a second parametric speaker (not shown) that similarly emits modulated ultrasonic waves with a frequency of at least 30 KHz. This second parametric speaker could:

(i) emit a wider beam of ultrasonic waves than the first parametric speaker 12;

(ii) be spaced from the first parametric speaker 12; or

(iii) emit a beam of ultrasonic waves that is angularly offset relative to the beam of ultrasonic waves 20 emitted by the first parametric speaker 12.

Such an arrangement, which includes a second parametric speaker would enable the timing system 10 to:

• communicate more encoded data to the smart communication device 14 by emitting a wider modulated ultrasonic wave beam, as the wider beam will take longer for an object 16 to cross and provide more time for transmission of encoded data; or

• emit a pair of opposing modulated ultrasonic wave beams that are directed away from each other, thereby to time objects 16 passing both infront of and behind the back-to-back pair of parametric speakers. According to a second aspect of the invention a method of operating a timing system 10 according to the first aspect of the invention, includes the following steps:

• emitting via a first parametric speaker 12 modulated ultrasonic waves 20 with a frequency of at least 30 KHz (preferably between 30 KHz and 100 KHz, and more preferably 40 KHz) and comprising:

(i) a carrier wave; and

(ii) a modulating wave that includes encoded data, as a narrow band, along a virtual line across a track 18;

• passing an object 16 through the modulated ultrasonic waves 20 emitted by the first parametric speaker 12 to cause the modulated ultrasonic waves 20 to demodulate by parametric interference into lower frequency waves;

• picking up the lower frequency demodulated waves via a microphone on a smart communication device 14 that is carried on or by the object 16, which microphone does not pick up waves with a frequency more than 25 KHz;

• using the lower frequency demodulated waves picked up by the smart communication device 14 microphone to determine timing; and

• (optionally) regulating emission of the modulated ultrasonic waves 20 from the first parametric speaker 12 via a sensor that senses proximity of an object 16 to the virtual line.

Optionally, the method could further include the step of emitting modulated ultrasonic waves with a frequency of at least 30 KHz via a second parametric speaker (not shown), which modulated ultrasonic waves emitted by the second parametric speaker is: wider than; spaced from; or angularly offset relative to, the modulated ultrasonic waves 20 emitted by the first parametric speaker 12.

It will be appreciated that prior art systems used speakers that emitted ultrasonic waves (as compared to modulated ultrasonic waves). As such, prior art systems required a device with a timer and a microphone that picked up ultrasonic waves with a frequency in the region of 40 KHz. Since this combination of features (i.e. timer and high frequency microphone) is not found in a common household device, operators of such prior art timing systems had to provide such devices to users. Not only is this costly, but impractical where the system is used by numerous casual users. Accordingly, such prior art timing systems have not been adopted widely. It was this problem that the current invention aimed to address. The first step was to identify a common household device with a timer and microphone: a smart communication device 14 (typically in the form of a mobile telephone). However, the smart communication device posed two problems:

(i) the smart communication device’s microphone typically does not pick up waves with a frequency greater than 25 KHz; and

(ii) to reduce the frequency of the emitted ultrasound to 25 KHz results in excessive diffraction of the waves, and consequently an inaccurate timing system.

To solve these problems, the current invention substituted emitted ultrasonic waves with emitted modulated ultrasonic waves. The emitted modulated ultrasonic waves are emitted at a frequency in the region of 40 KHz, thereby retaining an acceptably low diffraction property; however, upon striking an object, the modulated ultrasonic waves step down in frequency sufficiently to be picked up by the smart communication device microphone.