Dual technology motion sensor

• US 5,189,393 A
• Filed: 06/07/1991
• Issued: 02/23/1993
• Est. Priority Date: 06/07/1991
• Status: Expired due to Term

• Current Assignee: The Watt Stopper Incorporated (Legrand SA)
• Original Assignee: The Watt Stopper Incorporated (Legrand SA)
• Inventors: Hu, Charles C.
• Primary Examiner(s): Crosland, Donnie L.
• Application Number:
  US07/712,230
• Time in Patent Office: 627 Days
• Field of Search: 340/522, 340/521, 340/506, 340/565, 340/561, 340/554, 340/552, 340/555, 367/93, 367/94
• US Class Current: 340/522
• CPC Class Codes: G08B 13/1645 using ultrasonic detection means and other detection means, e.g. microwave or infrared radiation
• CPC Class Codes: G08B 13/2494 by interference with electro-magnetic field distribution combined with other electrical sensor means, e.g. microwave detectors combined with other sensor means
• CPC Class Codes: G08B 29/183 Single detectors using dual technologies G08B13/1672, G08B13/2448, G08B13/2494 take precedence

Abstract

A dual technology sensor which uses both ultrasonic and infrared sensors is disclosed. The electronic circuit of the invention requires detection by both sensors to activate the load. Thus, false triggering will not occur unless the false triggering device both emits heat and moves. The avoid having the motion sensor inadvertently turn off while the person is still present, only one of the infrared and ultrasonic sensors is required to be detecting to maintain the activated state.

Claims

1. A motion sensor for detecting motion and providing an activating signal to a load, comprising:

an ultrasonic transmitter;

an ultrasonic receiver for generating a first detection signal;

an infrared receiver for generating a second detection signal;

means for generating said activating signal when both said first and second detection signals are present;

means for maintaining said activating signal when only one of said first and second detection signals are present;

a photo sensor for producing a third detection signal; and

means for deactivating said activation signal when said third detection signal is beyond a predetermined threshold.

2. The motion sensor of claim 1 further comprising means for adjusting said predetermined threshold.

3. The motion sensor of claim 1 wherein said means for generating includes first logic means for providing an AND function of said first and second detection signals.

4. A motion sensor for detecting motion and providing an activating signal to a load, comprising:

an ultrasonic transmitter;

an ultrasonic receiver for generating a first detection signal;

an infrared receiver for generating a second detection signal;

means for generating said activating signal when both said first and second detection signals are present;

means for maintaining said activating signal when only one of said first and second detection signals are present;

a timer circuit, coupled to said means for generating, for maintaining said activating signal for a predetermined amount of time; and

a feedback circuit, included in said means for maintaining and coupled to an output of said timer circuit, for providing a delayed signal to said means for generating.

5. The motion sensor of claim 4 further comprising means for adjusting said amount of time.

6. A motion sensor comprising:

an oscillator;

a first driver coupled to an output of said oscillator;

an ultrasonic transmitter coupled to an output of said first driver;

an ultrasonic receiver;

a second amplifier coupled to an output of said ultrasonic receiver;

a filter coupled to said second amplifier;

an infrared receiver;

a third amplifier coupled to an output of said infrared receiver;

first logic means, having inputs coupled to said second and third amplifiers, for producing an ON signal in response to an active output of both of said second and third amplifiers;

second logic means, having a first input coupled to an output of said first logic means to receive said ON signal, and a second input, for producing an output signal in response to said ON signal and an active signal at said second input;

a timer circuit, having an input coupled to an output of said second logic means, for producing a timed signal for a predetermined amount of time;

a driver signal, having an input coupled to an output of said timer circuit, for providing an activating signal to a load;

a delayed feedback circuit, having an input coupled to said output of said timer circuit, for producing a feedback signal after a predetermined delay; and

third logic means, having inputs coupled to an output of said delayed feedback circuit, said output of said second amplifier and said output of said third amplifier, for providing an active signal to said second input of said second logic means in response to said feedback signal and a signal from one of said second and third amplifiers.

7. A motion sensor for detecting motion and providing an activating signal to a load, comprising:

an ultrasonic transmitter;

an ultrasonic receiver for generating a first detection signal;

an infrared receiver for generating a second detection signal;

means for generating said activating signal when both said first and second detection signals are present, said means for generating including first logic means for providing an AND function of said first and second detection signals; and

means for maintaining said activating signal when only one of said first and second detection signals are present, said means for maintaining including

second logic means for producing an AND function of said first detecting signal and a maintaining signal,

third logic means for producing an AND function of said second detection signal and said maintaining signal,

fourth logic means for producing an OR function of said second and third logic means, and

fifth logic means for producing an OR function of said first logic means and said fifth logic means.

8. The motion sensor of claim 7 wherein said maintaining signal is produced by a feedback signal from a feedback circuit coupled to receive said activating signal.

9. A motion sensor for detecting motion and providing an activating signal to a load, comprising:

an ultrasonic transmitter;

an ultrasonic receiver for generating a first detection signal;

an infrared receiver for generating a second detection signal;

means for generating said activating signal when both said first and second detection signals are present;

means for maintaining said activating signal when only one of said first and second detection signals are present;

a photo sensor for producing a third detection signal;

means for deactivating said activation signal when said third detection signal is beyond a predetermined threshold;

a timer circuit, coupled to said means for generating, for maintaining said activating signal for a predetermined amount of time; and

a feedback circuit, included in said means for maintaining and coupled to an output of said timer circuit, for providing a delayed signal to said means for generating.

10. The motion sensor of claim 9 further comprising means for adjusting said amount of time.

11. The motion sensor of claim 10 further comprising means for adjusting said predetermined threshold.

12. The motion sensor of claim 9 wherein said means for deactivating includes a comparator having a first input coupled to an output of said timer circuit and a second input coupled to an output of said feedback circuit.