Sensing device and method of calibration

• US 9,739,863 B2
• Filed: 01/21/2013
• Issued: 08/22/2017
• Est. Priority Date: 01/20/2012
• Status: Expired due to Fees

• Current Assignee: Legrand Electrical Company Limited (Legrand SA)
• Original Assignee: C.P. Electronics Limited (Legrand SA)
• Inventors: Milner, Merlin, Mans, Paul, Margetts-Kelly, Andrew
• Primary Examiner(s): Bythrow, Peter
• Application Number:
  US14/373,458
• Publication Number:
  US 20150002170A1
• Time in Patent Office: 1,674 Days
• CPC Class Codes: G01R 35/005 Calibrating; Standards or reference devices, e.g. voltage or resistance standards, "golden" references G01R33/0035, G01R35/002 take precedence
• CPC Class Codes: G01S 13/56 for presence detection presence detection using near field arrangements G01V3/00, e.g. G01V3/08, G01V3/12; burglar, theft or intruder alarms with electrical actuation G08B13/22 - G08B13/26
• CPC Class Codes: G01S 17/50 Systems of measurement based on relative movement of target
• CPC Class Codes: G01S 7/003 Transmission of data between radar, sonar or lidar systems and remote stations
• CPC Class Codes: G01S 7/021 Auxiliary means for detecting or identifying radar signals or the like, e.g. radar jamming signals
• CPC Class Codes: G01S 7/292 Extracting wanted echo-signals
• CPC Class Codes: G01S 7/36 Means for anti-jamming , e.g. ECCM, i.e. electronic counter-counter measures
• CPC Class Codes: G08B 13/2491 Intrusion detection systems, i.e. where the body of an intruder causes the interference with the electromagnetic field
• CPC Class Codes: G08B 29/18 Prevention or correction of operating errors G08B29/02, G08B29/12 take precedence
• CPC Class Codes: G08B 29/26 by updating and storing reference thresholds
• CPC Class Codes: H05B 47/115 by determining the presence or movement of objects or living beings
• CPC Class Codes: H05B 47/19 via wireless transmission
• CPC Class Codes: Y02B 20/40 Control techniques providing energy savings, e.g. smart controller or presence detection

Abstract

A sensing device comprises a microwave sensor (1) configured to emit microwave radiation and to receive microwave radiation reflected by a moving body in the field of detection of the microwave sensor and a wireless data transmitter (4) configured to transmit data to a remote receiver. A main power supply provides electrical power at a first voltage to the sensing device. A first regulator 6 provided between the main power supply and the microwave sensor (1) provides a sensor power supply to the microwave sensor (1) at a voltage below the voltage of the main power supply. The wireless data transmitter (4) is powered from the main power supply via a transmitter power supply connection arranged in parallel with the first regulator (6). The microwave sensor (1) is provided on a first circuit board and the wireless data transmitter (4) is provided on a second circuit board, with the second circuit board overlying the first circuit board and spaced therefrom. A signal processing device is configured to receive an output signal from the microwave sensor and to generate an occupancy signal indicative of the presence of a moving body in the field of detection of the microwave sensor (1) when the output signal of the microwave (1) sensor (1) exceeds a threshold level. The signal processing device is configured to increase the threshold level temporarily during data transmission by the wireless data transmitter (4), in order to compensate for RF interference due to the data transmission.

Claims

1. A sensing device comprising:

a microwave sensor configured to emit microwave radiation and to receive microwave radiation reflected by a moving body in the field of detection of the microwave sensor;

a wireless data transmitter configured to transmit data to a remote receiver, a main power supply for providing electrical power at a first voltage to the sensing device,

a first regulator provided between the main power supply and the microwave sensor for providing a sensor power supply to the microwave sensor at a voltage below the voltage of the main power supply,

wherein the wireless data transmitter is powered from the main power supply via a transmitter power supply connection arranged in parallel with the first regulator.

2. A sensing device as claimed in claim 1 further comprising a second regulator provided between the main power supply and the wireless data transmitter in parallel with the first regulator for providing a transmitter power supply to the wireless data transmitter at a voltage below the voltage of the main power supply.

3. A sensing device as claimed in claim 1, wherein a first inductor is provided between the transmitter power supply connection and the first regulator.

4. A sensing device as claimed in claim 1, wherein a second inductor is provided in the transmitter power supply connection to the wireless data transmitter.

5. A sensing device as claimed in claim 1, wherein a third inductor is provided in the return path of the sensor power supply.

6. A sensing device as claimed in claim 1, wherein a fourth inductor is provided in the return path of the transmitter power supply in parallel with the return path of the sensor power supply.

7. A sensing device as claimed in claim 1, wherein the voltage of the main power supply is in the range 10V to 18V.

8. A sensing device as claimed in claim 1, wherein the voltage of the sensor power supply is in the range 1 V to 7V.

9. A sensing device as claimed in claim 1, wherein the voltage of the transmitter power supply is in the range 1 V to 7V.

10. A sensing device as claimed in claim 1, wherein the microwave sensor is provided on a first circuit board and the wireless data transmitter is provided on a second circuit board, with the second circuit board overlying the first circuit board and spaced therefrom.

12. A sensing device as claimed in claim 10, wherein the electrical connections between the first circuit board and the second circuit board comprise one or more inductors for suppressing radio frequency interference of the microwave sensor by the wireless data transmitter.

13. A sensing device as claimed in claim 10, wherein the second circuit board comprises an antenna for the wireless data transmitter and the second circuit board forms a ground plane for the antenna.

14. A sensing device as claimed in claim 10, wherein a layer of radar absorptive material is interposed between the first circuit board and the second circuit board.

15. A sensing device as claimed in claim 1 further comprising a signal processing device configured to receive an output signal from the microwave sensor and to generate an occupancy signal indicative of the presence of a moving body in the field of detection of the microwave sensor when the output signal exceeds a threshold level,

wherein the signal processing device is configured to increase the threshold level temporarily during data transmission by the wireless data transmitter, whereby to compensate for RF interference due to the data transmission.

17. A method of calibrating a sensing device as claimed in claim 15, the method comprising:

determining that the output signal from the microwave sensor has been at a low level indicative of the absence of a moving body in the field of detection of the microwave sensor for a period of time;

transmitting data using the wireless data transmitter;

during data transmission measuring the output signal from the microwave sensor;

determining on the basis of the measured output signal an amount by which the threshold level shall be increased temporarily during data transmission to compensate for RF interference due to the data transmission.

18. The method of claim 17 comprising the subsequent steps of:

waiting for a predetermined period of time and repeating the method of claim 17;

comparing the first threshold increase amount determined to the second threshold increase amount determined, whereby to confirm that the determined threshold amounts are representative of RF interference due to the data transmission.

19. The method of claim 17 comprising the subsequent step of:

determining that the output signal from the microwave sensor has continued for a period of time at a low level indicative of the absence of a moving body in the field of detection of the microwave sensor.

20. A sensing device as claimed in claim 15 comprising a data processing device configured to control calibration of the sensing device by causing the sensing device to

determine that the output signal from the microwave sensor has been at a low level indicative of the absence of a moving body in the field of detection of the microwave sensor for period of time;

transmit data using the wireless data transmitter;

measure during data transmission the output signal from the microwave sensor; and

determine on the basis of the measured output signal an amount by which the threshold level shall be increased temporarily during data transmission to compensate for RF interference due to the data transmission.

21. A sensing device as claimed in claim 20, wherein the signal processing device is provided by the data processing device.

11. A sensing device comprising:

a microwave sensor configured to emit microwave radiation and to receive microwave radiation reflected by a moving body in the field of the detection of the microwave sensor; and

a wireless data transmitter configured to transmit data to a remote receiver, wherein the microwave sensor is provided on a first circuit board and the wireless data transmitter is provided on a second circuit board, with the second circuit board overlying the first circuit board and spaced therefrom.

16. A sensing device comprising:

a microwave sensor configured to emit microwave radiation and to receive microwave radiation reflected by a moving body in the field of the detection of the microwave sensor;

a wireless data transmitter configured to transmit data to a remote receiver; and

a signal processing device configured to receive an output signal from the microwave sensor and to generate an occupancy signal indicative of the presence of a moving body in the field of detection of the microwave sensor when the output signal exceeds a threshold level,

wherein the signal processing device is configured to increase the threshold level temporarily during data transmission by the wireless data transmitter, whereby to compensate for RF interference due to the data transmission.