Method and apparatus to communicate with and individually locate multiple remote devices on a two-dimensional surface

• US 20050230609A1
• Filed: 03/17/2005
• Published: 10/20/2005
• Est. Priority Date: 03/19/2004
• Status: Active Grant

• Current Assignee: Mitch Randall
• Original Assignee: Mitch Randall
• Inventors: Randall, Mitch
• Granted Patent: US 7,294,822 B2
• Time in Patent Office: Days
• US Class Current: 250/234
• CPC Class Codes: A63B 2024/0025 Tracking the path or location of one or more users, e.g. players of a game
• CPC Class Codes: A63B 2024/0028 Tracking the path of an object, e.g. a ball inside a soccer pitch
• CPC Class Codes: A63B 2024/0031 at the starting point
• CPC Class Codes: A63B 2220/10 Positions
• CPC Class Codes: A63B 2220/805 Optical or opto-electronic sensors
• CPC Class Codes: A63B 2220/89 Field sensors, e.g. radar systems
• CPC Class Codes: A63B 2225/54 Transponders, e.g. RFID
• CPC Class Codes: A63B 24/0021 Tracking a path or terminating locations
• CPC Class Codes: A63B 71/06 Indicating or scoring devices for games or players , or for other sports activities
• CPC Class Codes: G01S 5/16 using electromagnetic waves other than radio waves

Abstract

A method and apparatus is provided by the invention whereby a base station communicates with and determines the position of multiple remote devices on a two-dimensional surface. In one embodiment the base station employs a single channel radio transmitter, an infrared detector, and an infrared projecting apparatus. The radio transmitter sends a continuous stream of addressed and time-multiplexed commands to the multiple remote devices. The multiple remote devices receive commands and time synchronization from the radio signal. The projecting apparatus is located above the two-dimensional surface and projects an alternating pair of orthogonal, sweeping, infrared, line-shaped, illumination areas upon it with deterministic timing. Each remote device detects the passage of the sweeping infrared line-shaped illumination areas over it. The measured timing is used to derive the two dimensional position aboard the remote device which is then communicated back to the base station by an infrared data link.

Claims

1. An apparatus for determining a position of a remote device located on a two dimensional surface comprising:

an optical scanning apparatus located above the two-dimensional surface for projecting an optical sweep line approximately perpendicular to a first axis from a first position to a second position of the two-dimensional surface along a first axis, the projection apparatus having a predetermined relationship between a position of the optical sweep line along the first axis and time;

a base station for transmitting of a RF signal comprising embedded timing information to the remote device, where the remote device receives the RF signal and decodes the embedded timing information,

wherein when the scanning apparatus initiates an optical line scan at the first position, a start time is provided to the base station and to the remote device;

wherein when the remote device is illuminated by the optical sweep line it records a time of the event and thereafter provides the event time information to the base station, where the event time information and the start time are used for determining the position of the remote device along the first axis and between the first and second positions.

2. An apparatus according to claim 1 wherein the remote device comprises an optical detector for detecting of the optical sweep line.

3. An apparatus according to claim 2 wherein the remote device comprises a remote device control circuit comprising a counter and coupled with the optical detector for generating a control signal upon detecting light from the optical sweep line, wherein the counter is reset when the start time is provided and incremented during the optical sweep until the control signal is provided from the optical detector, where the time information is derived from a value of the counter.

4. A method of determining a position of a remote device disposed between a first position and a second position along a first axis comprising:

receiving of an embedded timing information signal at the remote device;

providing an optical scanning apparatus for scanning an optical sweep line;

predetermining a relationship between a position along the first axis for the optical sweep line and time for scanning from the first position to the second position;

positioning the optical sweep line at the first position;

resetting a counter within the remote device when the optical sweep line is at the first position;

providing a start time with reference to a timing signal for the remote device and for the scanning of the optical sweep line using the scanning apparatus;

scanning the optical sweep line from the first position to the second position incrementing the counter during the scanning at a predetermined rate that is derived from the embedded timing information signal;

terminating incrementing of the counter at the remote device upon receiving of light at the remote device from the optical sweep line during the scanning; and

,

determining a position of the remote device between the first and second positions in dependence upon data derived from the counter, the start time and the predetermined relationship.

5. A method according to claim 4 comprising providing a clock signal for generating of the timing information for the embedded timing information signal, wherein the counter is incremented at an approximately same rate as the clock signal.

6. A method according to claim 5 wherein the position of the remote device is determined from a fraction of the predetermined amount of time.

7. A method according to claim 4 wherein the scanning of the optical sweep line is at a predetermined synchronization to the embedded timing information signal.

8. A method for determining a position of a device on a two-dimensional surface, comprising:

sweeping a first elongated line of light in a first direction across the surface in a manner that illuminates the device on the surface as the first elongated line of light moves over the device;

monitoring where the first line of light is located on the surface on a real time basis;

detecting the light that illuminates the device as the first elongated line of light sweeps across the surface and correlating timing of such detection of light with the position of the first elongated line of light at the time the light illuminating the device is detected to determine a first direction coordinate position of the device on the surface;

sweeping a second elongated line of light in a second direction across the surface in a manner that illuminates the device on the surface as the second elongated line of light moves over the device;

monitoring where the second line of light is located on the surface on a real time basis; and

detecting the light that illuminates the device as the second elongated line of light sweeps across the surface and correlating timing of such detection of light with the position of the second elongated line of light at the time the light illuminating the device is detected to determine a second direction coordinate position of the device on the surface.

9. The method of claim 8, wherein the first direction and the second direction are orthogonal to each other.

10. The method of claim 9, wherein the first direction coordinate an X value and the second direction coordinate is a Y value.

11. Apparatus for detecting a position of a device on a surface, comprising:

a light detector on the device;

means for producing and sweeping a first line of light in a first direction across said surface;

means for producing and sweeping a second line of light in a second direction across said surface;

means for monitoring positions of the first line of light on the surface in real time as the first line of light sweeps across the surface;

means for monitoring positions of the second line of light on the surface in real time as the second line of light sweeps across the surface;

means for correlating time of detection of light by the light detector on the device with the position of the first line of light on the surface at that time for a first direction coordinate of the position of the device on the surface or with the position of the second line of light on the surface at that time for a second direction coordinate of the position of the device on the surface.

12. The apparatus of claim 11, wherein said means for producing and sweeping a first line of light in a first direction across said surface includes:

a rotatable drum that is rotatable about a longitudinal axis of rotation and having a cylindrical wall with an elongated slot oriented parallel to the longitudinal axis of rotation positioned at a distance from the surface;

a light source positioned in the drum; and

a drive mechanism connected to the drum that rotates the drum in relation to the surface.

13. The apparatus of claim 12, wherein said means for producing and sweeping a second line of light in a second direction across said surface includes:

a rotatable drum that is rotatable about a longitudinal axis of rotation and having a cylindrical wall with an elongated slot oriented parallel to the longitudinal axis of rotation positioned at a distance from the surface.

14. The apparatus of claim 12, wherein said means for producing and sweeping a first line of light in a first direction across said surface includes:

a rotatable drum that is rotatable about a longitudinal axis of rotation and having a cylindrical wall with an elongated cylindrical lens oriented parallel to the longitudinal axis of rotation positioned at a distance from the surface;

a light source positioned in the drum; and

a drive mechanism connected to the drum that rotates the drum in relation to the surface.

15. The apparatus of claim 11, wherein said means for producing and sweeping a second line of light in a second direction across said surface includes:

a rotatable drum that is rotatable about a longitudinal axis of rotation and having a cylindrical wall with an elongated cylindrical lens oriented parallel to the longitudinal axis of rotation positioned at a distance from the surface.

16. The apparatus of claim 11, wherein said means for producing and sweeping a first line of light in a first direction across said surface includes:

a rotating mirror positioned at a distance from the surface and that rotates about an axis of rotation that is parallel to the surface; and

a light source adjacent the rotating mirror and oriented to direct a line of light on the mirror.

17. The apparatus of claim 11, wherein said means for producing and sweeping a first line of light in a first direction across said surface includes:

an oscillating mirror positioned at a distance from the surface and that oscillates about an axis that is parallel to the surface; and

a light source adjacent the oscillating mirror and oriented to direct a line of light on the mirror.

18. The apparatus of claim 17, wherein the light source directs the line of light on the mirror intermittently.

19. The apparatus of claim 11, wherein said means for producing and sweeping a first line of light in a first direction across aid surface includes:

a spatial light modulator array positioned at a distance from the surface;

a light source adjacent the spatial light modulator and oriented to direct a beam of light on the spatial light modulator; and

a control circuit connected to the spatial light modulator programmed to drive the spatial light modulator to direct a sequence of lines of light on the surface to simulate the line of light sweeping across the surface.