Proximity detection system and method and collision avoidance system and method using proximity detection
The invention relates to a complex proximity safety and warning system. The invention provides a safety system comprising a generator that generates a magnetic field that establishes a boundary, where the generator is capable of receiving radio frequency signals. Also provided is a radio frequency device that sends radio frequency signals, the radio frequency device being capable of sensing the magnetic field and generating a radio frequency response.
1. A method, comprising the steps of:
generating, by a magnetic field generator, a magnetic field during a first time period;
sensing by an alarm device the magnetic field and generating a response signal during a second time period; and
sensing by the magnetic field generator for the response signal within a second time period, wherein the second time period comprises a plurality of time portions;
wherein the alarm device generates the response signal during a first number of time portions when the alarm device detects the magnetic field at a first strength and generates the response signal during a second number of time portions when the alarm device detects the magnetic field at a second strength.
2. The method of claim 1 , wherein the first strength is less than the second strength and first number of time portions is less than the second number of time portions.
3. The method of claim 2 , wherein the response during the first number of time portions indicates the alarm device is in a warning zone.
4. The method of claim 2 , wherein the response during the second number of time portions indicates the alarm device is in a danger zone.
5. The method of claim 4 , wherein the second number of time portions is all of the plurality of time portions.
6. A safety system, comprising:
a generator that generates a magnetic field, the generator being configured to receive at least one response signal; and
an alarm device adapted to sense the magnetic field and generate the response signal;
wherein the generator generates said magnetic field during a first time period, and senses for a response signal from the alarm device within a second time period, wherein the second time period comprises a plurality of time portions;
wherein the alarm device is adapted to generate the response signal during a first number of time portions when the alarm device detects the magnetic field at a first strength, and
wherein the alarm device generates the response signal during a second number of time portions when the alarm device detects the magnetic field at a second strength.
7. The safety system of claim 1 , wherein the generator is positioned at a vehicle.
8. The safety system of claim 7 , wherein the alarm device is positioned at least one of a dump point, a loading dock, or a person.
9. The safety system of claim 7 , wherein the vehicle is a first vehicle, and the safety system further comprises a second vehicle, the alarm device being positioned at the second vehicle.
10. The safety system of claim 9 , wherein the generator is a first generator and the alarm device is a first alarm device, and the safety system further comprises:
a second generator similar to the first generator, and a second alarm device similar to the first alarm device;
the second generator being positioned at the second vehicle, and the second alarm device being positioned at the first vehicle.
11. The safety system of claim 10 , further comprising:
a first circuit connecting the first generator and the second alarm device, wherein the circuit is adapted to disable the second alarm device during the time the first generator generates the magnetic field.
12. The safety system of claim 10 , wherein the second alarm device is adapted to generate an alarm when it senses the magnetic field of the second generator.
13. The safety system of claim 1 , wherein the first strength is less than the second strength and first number of time portions is less than the second number of time portions.
14. The safety system of claim 6 , further comprising:
a plurality of vehicles;
a plurality of generators, each similar to the generator;
a plurality of alarm devices, each similar to the alarm device;
each of said vehicles having a corresponding one of the generators and alarm devices.
15. The collision avoidance system of claim 6 , wherein said generator is adapted to sense for the response signals from said alarm device after a predetermined time delay.
16. The safety system of claim 6 , wherein said generator is adapted to be turned on and off to generate pulses of said magnetic field.
17. The safety system of claim 6 , further comprising multiple generators, wherein said multiple generators generate oscillating magnetic fields sequentially and not at the same time.
18. The safety system of claim 6 , wherein said magnetic field is adapted to operate at a low frequency of approximately 73 kHz.
19. The safety system of claim 6 , further comprising multiple generators that generate oscillating magnetic fields in a random manner within selected periods of time.
20. The safety system of claim 19 , wherein said alarm device senses strengths of magnetic fields from said multiple generators and differentiates between said strengths to determine whether values have been exceeded and to produce an alarm that gives priority to the higher levels of said sensed strengths.
21. The safety system of claim 6 , wherein said alarm device is adapted to measure a strength of said magnetic field, and if the field strength exceeds a predetermined value, generates an alarm.
22. The collision avoidance system of claim 6 , wherein a size of the magnetic field is modified by changing a width of a waveform input to a tuned circuit of the generator.
23. The system of claim 6 , wherein the generator is configured to send a signal to shut down the vehicle upon sensing a response signal of a predetermined strength.
24. The system of claim 6 , wherein the response during the first number of time portions indicates the alarm device is in a warning zone.
25. The system of claim 6 , wherein the response during the second number of time portions indicates the alarm device is in a danger zone.
26. The system of claim 25 , wherein the second number of time portions is all of the plurality of time portions.