1. A magnetic field sensor comprising:
a substrate having a surface;
a first magnetoresistive sensor comprising:
a first sensing element having a first side lying parallel to the surface of the substrate, and a second side opposed to the first side and having first and second opposed edges; and
a first flux guide disposed adjacent to the first side of the sensing element and having an end that is proximate to the first edge and the first side of the sensing element,
wherein the first sensing element defines a first long axis and a first plane through the first long axis, the first plane being perpendicular to the surface;
a second magnetoresistive sensor comprising:
a second sensing element having a first side lying parallel to the surface of the substrate, the second sensing element having a second side opposed to the first side and having first and second opposed edges; and
a second flux guide disposed adjacent to the first side of the second sensing element and having an end that is proximate to the second edge and the first side of the second sensing element,
wherein the second sensing element defines a second long axis and a second plane through the second long axis, the second plane being perpendicular to the surface;
a third magnetoresistive sensor comprising:
a third sensing element having a first side lying parallel to the surface of the substrate, the third sensing element having a second side opposed to the first side and having first and second opposed edges; and
a third flux guide disposed adjacent to the first side of the third sensing element and having an end that is proximate to the second edge and the first side of the third sensing element; and
a fourth magnetoresistive sensor comprising:
a fourth sensing element having a first side lying parallel to the surface of the substrate, the fourth sensing element having a second side opposed to the first side and having first and second opposed edges; and
a fourth flux guide disposed adjacent to the first side of the fourth sensing element and having an end that is proximate to the first edge and the first side of the fourth sensing element;
a first pair of self-test current carrying lines, the first pair of self-test current carrying lines including a first and a second self-test current carrying line disposed parallel to the second side of the first sensing element and spaced away from the first and second edges of the first sensing element, the first and second self-test current carrying lines being equidistant from, parallel to, and on opposed sides of the first plane and configured to create a magnetic field that is orthogonal to a sensor plane of the first, second, third, and fourth magnetoresistive sensors, wherein a first component of a first magnetic field in a third plane that is parallel to the surface and created by a first current in a first direction in the first self-test current carrying line, and a second component of a second magnetic field in the third plane and created by a second current in a second direction in the second self-test current carrying line cancel one another at the intersection of the first plane and the first long axis of the sensing element, and components of the first and second magnetic fields that are parallel to the first plane are additive at the first flux guide and a portion of the components of the first and second magnetic fields that are parallel to the first plane are guided into the sensing element as a third component, wherein the first and second self-test current carrying lines are disposed parallel to the second side of the third sensing element and spaced away from the first and second edges of the third sensing element; and
a second pair of self-test current carrying lines disposed parallel to the second side of the second sensing element and spaced away from the first and second edges of the second sensing element, each self-test current carrying line of the second pair being equidistant from, parallel to, and on opposed sides of the second plane and configured to create a magnetic field that is orthogonal to the sensor plane of the first, second, third, and fourth magnetoresistive sensors, wherein the second pair of self-test current carrying lines are disposed parallel to the second side of the fourth sensing element and spaced away from the first and second edges of the fourth sensing element,
wherein the first, second, third, and fourth magnetoresistive sensors are coupled in a Wheatstone bridge configuration, the first and second magnetoresistive sensors are connected in parallel, the first and third magnetoresistive sensors are coupled in series, and the second and fourth magnetoresistive sensors are coupled in series.
2. The magnetic field sensor of claim 1, wherein the third component comprises a magnitude that is proportional to the size and shape of the first flux guide and inversely proportional to the distance between the first flux guide and the first sensing element.
3. The magnetic field sensor of claim 1, wherein the first flux guide comprises a high permeability material.
4. The magnetic field sensor of claim 1, comprising a stabilization line perpendicular to the first pair of self-test current carrying lines and adjacent the first magnetoresistive sensor.
5. A magnetic field sensor comprising:
a substrate having a planar surface; and
a first bridge circuit comprising a first magnetoresistive sensor, a second magnetoresistive sensor, a third magnetoresistive sensor, and a fourth magnetoresistive sensor coupled as a Wheatstone bridge for sensing a magnetic field in a first direction that is orthogonal to a plane of the first, second, third, and fourth magnetoresistive sensors;
the first magnetoresistive sensor comprising:
a first sensing element having a first side lying parallel to the planar surface of the substrate, the first sensing element having a second side opposed to the first side and having first and second opposed edges; and
a first flux guide disposed orthogonal to and spaced from the first edge of the first sensing element;
the second magnetoresistive sensor comprising:
a second sensing element having a first side lying parallel to the planar surface of the substrate, the second sensing element having a second side opposed to the first side and having first and second opposed edges; and
a second flux guide disposed orthogonal to and spaced from the second edge of the second sensing element;
the third magnetoresistive sensor comprising:
a third sensing element having a first side lying parallel to the planar surface of the substrate, the third sensing element having a second side opposed to the first side and having first and second opposed edges; and
a third flux guide disposed orthogonal to and spaced from the second edge of the third sensing element; and
the fourth magnetoresistive sensor comprising:
a fourth sensing element having a first side lying parallel to the planar surface of the substrate, the fourth sensing element having a second side opposed to the first side and having first and second opposed edges; and
a fourth flux guide disposed orthogonal to and spaced from the first edge of the fourth sensing element,
wherein the first, second, third, and fourth, sensing elements define a first plane, and
wherein the first bridge circuit further comprises:
a first self-test current carrying line and a second self-test current carrying line disposed parallel to the second side of the first and third sensing elements and spaced away from the first and second edges of the first and third sensing elements, the first and second self-test current carrying lines being equidistant from, parallel to, and on opposed sides of a second plane perpendicular to the first plane and configured to create a magnetic field that is orthogonal to the plane of the first, second, third, and fourth magnetoresistive sensors of the first bridge circuit;
a third self-test current carrying line and a fourth self-test current carrying line disposed parallel to the second side of the second and fourth sensing elements and spaced away from the first and second edges of the second and fourth sensing elements, the third and fourth self-test current carrying lines being equidistant from, parallel to, and on opposed sides of a third plane perpendicular to the first plane, and configured to create a magnetic field that is orthogonal to the plane of the first, second, third, and fourth magnetoresistive sensors of the first bridge circuit.
6. The magnetic field sensor of claim 5, wherein a first component of a first magnetic field in a fourth plane parallel to the planar surface and created by a first current in a first direction in the first self-test current carrying line, and a second component of a second magnetic field in the fourth plane and created by a second current in a second direction in the second self-test current carrying line cancel one another at the intersection of the second plane and a first long axis of the first and third sensing elements, and the first and second magnetic field components parallel to the second plane are additive at the first and third flux guides, and a portion of components orthogonal to the plane of the first, second, third, and fourth magnetoresistive sensors of the first bridge circuit are guided into the first and third sensing elements as a third component.
7. The magnetic field sensor of claim 6, wherein the third component comprises a magnitude that is proportional to a size and a shape of the first flux guide and inversely proportional to a distance between the first flux guide and the first sensing element.
8. The magnetic field sensor of claim 5, wherein at least one of the first, second, and third flux guides includes a high permeability magnetic material.
9. The magnetic field sensor of claim 8, wherein the high permeability magnetic material of the at least one of the first, second, and third flux guides includes a soft ferromagnetic material.
10. The magnetic field sensor of claim 8, wherein the high permeability magnetic material includes nickel iron.
11. The magnetic field sensor of claim 5, wherein one or more of the first, second, third, and fourth flux guides is disposed below the first, second, third, and fourth sensing elements, respectively.
12. The magnetic field sensor of claim 5, further comprising:
a first stabilization line perpendicular to the first, second, third, and fourth self-test current carrying lines and adjacent the first and second sensing elements.
13. The magnetic field sensor of claim 12, further comprising:
a second stabilization line perpendicular to the first, second, third, and fourth self-test current carrying lines and adjacent the third and fourth sensing elements.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A warning system applied for a vehicle, the vehicle comprising a seat, the system comprising:
a control module,
a detecting module assembled to the vehicle and electrically coupled to the control module;
a warning module assembled to the vehicle and electrically coupled to the control module; and
a pressure sensor module assembled to a seat of the vehicle and electrically coupled to the control module;
wherein the pressure sensor module is configured to measure a pressure value of the seat and transmit the pressure value to the control module, the control module is configured to calculate a pressure difference between the pressure value and a predetermined value to determine whether there is at least one person sitting on the seat; and
wherein the detecting module is configured to obtain information of the environment around the vehicle and transmit the information to the control module, and the control module is further configured to determine whether there is a passing vehicle based on the information and control the warning module to warn the passing vehicle when there is someone sitting on the seat and there is a passing vehicle.
2. The warning system of claim 1, wherein the detecting module comprises an ultrasonic detecting unit, the ultrasonic detecting unit is configured to transmit and receive ultrasonic signals, and is capable of measuring a distance module between the vehicle and another vehicle based on the ultrasonic signals and transmitting the distance value to the control module, the control module is configured to analyze the distance value to determine whether there is a passing vehicle.
3. The warning system of claim 1, wherein the detecting module comprises a camera unit, the camera unit is configured to take images around the vehicle and transmit the images to the control module, the control module is configured to analyze the images to determine whether there a passing vehicle.
4. The warning system of claim 1, wherein the warning module comprises a lamp warning unit, the control module control the lamp warning unit to warn the passing vehicle.
5. The warning system of claim 1, wherein the warning module comprises a voice warning unit, the control module control the voice warning unit to warn the passing vehicle.
6. The warning system of claim 1, wherein the warning system further comprises a power source module, the control module, the pressure sensor module, the detecting module, and the warning module are electrically coupled to the power source module respectively.
7. The warning system of claim 1, wherein the detecting module is configured to obtain the information within an area around the vehicle less then predetermined distance.
8. The warning system of claim 1, wherein the detecting module is assemble to a side of the vehicle.
9. The warning system of claim 1, wherein the warning module is assembled to a top surface of the vehicle.
10. A warning method applied to a vehicle, the vehicle comprising a seat, the method comprising:
measuring a pressure value of the seat;
calculating a pressure difference between the pressure value and a predetermined value to determine whether there is at least one person sitting on the seat;
obtaining information of the environment around the vehicle;
determining whether there is a passing vehicle based on the information; and
warning the passing vehicle when there is at least one person sitting on the seat and there is a passing vehicle.
11. The warning method of claim 10, wherein the method further comprises:
transmitting and receiving ultrasonic signals to obtaining the information of the environment around the vehicle.
12. The warning method of claim 10, wherein the method further comprises:
taking images around the vehicle to obtain the information of the environment around the vehicle.
13. The warning method of claim 10, wherein the vehicle comprises a warning module comprising a lamp warning unit, the method further comprises: controlling the lamp warning unit to warn the passing vehicle when there is at least one person sitting on the seat and there is a passing vehicle.
14. The warning method of claim 10, wherein the vehicle comprises a warning module comprising a voice warning unit, the method further comprises: controlling the voice warning unit to warn the passing vehicle when there is at least one person sitting on the seat and there is a passing vehicle.