Classroom noise alarm

• US 4,346,374 A
• Filed: 01/05/1981
• Issued: 08/24/1982
• Est. Priority Date: 01/05/1981
• Status: Expired due to Fees

• Current Assignee: James W. Groff
• Original Assignee: James W. Groff
• Inventors: Groff, James W.
• Primary Examiner(s): Swann, III, Glen R.
• Application Number:
  US06/222,304
• Time in Patent Office: 596 Days
• Field of Search: 340/566, 340/573, 340/540, 340/501, 340/527, 179/1 N, 307/117, 181/0.5
• US Class Current: 340/573.1
• CPC Class Codes: G08B 21/182 Level alarms, e.g. alarms responsive to variables exceeding a threshold

Abstract

A noise alarm for use in a school classroom to detect sound exceeding a predetermined level and which actuates a two-tone audio alarm and a light-emitting diode to notify both the instructor and students when excessive noise has been detected. The noise alarm aids the instructor in preventing excessive classroom noise which can and does disrupt and destroy a given learning situation. A sensitivity control is provided to allow the instructor to determine the noise level at which the alarm will automatically respond, and time delay means are provided so the audio alarm will not sound unless excessive noise occurs twice and within a predetermined time frame. The noise alarm also provides a digital LED readout displaying how many times the audio alarm has been triggered, thus providing the instructor with a temporary record which can be used to reinforce acceptable classroom noise levels. Other controls are also provided, allowing the instructor to "erase" the count displayed or to place the noise alarm in a "hold" mode so that the alarm is temporarily disabled without disturbing any count which is currently displayed by the LED readout.

Claims

1. A classroom noise alarm for aiding the teacher in maintaining discipline comprising in combination:

a power supply circuit for energizing said classroom noise alarm;

a switch for actuating said power supply circuit of said classroom noise alarm;

audible alarm means;

a microphone for detecting noise occuring within a school classroom;

an audio amplifier coupled with said microphone for amplifying the output thereof;

adjustable resistance means coupled to the output of said audio amplifier for controlling the amplitude of an amplified noise signal;

a sound-actuated switch coupled to the output of said adjustable resistance means and comprising an operatively associated audio input transformer, rectifieto the trigger of said second monostable multivibrator, the output thereof being connected to a second input terminal of said logic gate, thereby preventing said logic control signal of said sound-actuated switch from being conducted through said logic gate except during a predetermined time delay of said second monostable multivibrator occuring subsequent to a prior, predetermined time delay of said first monostable multivibrator for initiating actuation of said audible alarm means only after repeated classroom noise occuring within a specified timed interval;

a second timing means, the trigger thereof being connected to the output of said logic gate of said first timing and control logic means and the output being connected to said audible alarm means for controlling actuation and duration of said audible alarm means; and

counting and readout means operatively associated with said second timing means for counting and displaying the exact number of times said audible alarm means are actuated by classroom noise.

2. A classroom noise alarm for aiding the teacher in maintaining discipline comprising in combination:

a power supply circuit for energizing said classroom noise alarm;

a switch for actuating said power supply circuit of said classroom noise alarm;

audible alarm means;

a microphone for detecting noise occuring within a school classroom;

an audio amplifier coupled with said microphone for amplifying the output thereof;

adjustable resistance means coupled to the output of said audio amplifier for controlling the amplitude of an amplified noise signal;

a sound-actuated switch coupled to the output of said adjustable resistance means and comprising an operatively associated audio input transformer, rectifier diode, filter capacitor, amplifier transistor, and switching transistor for providing a logic control signal in response to the output of said audio amplifier when classroom noise exceeds a predetermined level as determined by said adjustable resistance means;

holding means comprising a DPDT switch connected to the output of said sound-actuated switch, the first terminals of said DPDT switch conducting said logic control signal of said sound-actuated switch when said DPDT switch is in a first, non-hold position and the second terminals energizing a light-emitting diode hold indicator when said DPDT switch is in a second, hold position for disabling said classroom noise alarm without disrupting power thereto and for indicating a hold condition to students and instructor;

a first timing and control logic means comprising a first and second monostable multivibrator, edge detector, and logic gate, the trigger of said first monostable multivibrator and a first input terminal of said logic gate being operatively connected to the output of said sound-actuated switch when said DPDT switch is in a said non-hold position, the output of said first monostable multivibrator being connected in series with said edge detector to the trigger of said second monostable multivibrator, the output thereof being connected to a second input terminal of said logic gate, thereby preventing said logic control signal of said sound-actuated switch from being conducted through said logic gate except during a predetermined time delay of said second monostable multivibrator occuring subsequent to a prior, predetermined time delay of said first monostable multivibrator for initiating actuation of said audible alarm means only after repeated classroom noise occuring within a specified timed interval;

a second timing means, the trigger thereof being connected to the output of said logic gate of said first timing and control logic means and the output being connected to said audible alarm means for controlling actuation and duration of said audible alarm means; and

counting and readout means operatively associated with said second timing means for counting and displaying the exact number of times said audible alarm means are actuated by classroom noise.

3. A classroom noise alarm for aiding the teacher in maintaining discipline comprising in combination:

a power supply circuit for energizing said classroom noise alarm;

a switch for actuating said power supply circuit of said classroom noise alarm;

audible alarm means;

a microphone for detecting noise occuring within a school classroom;

an audio amplifier coupled with said microphone for amplifying the output thereof;

adjustable resistance means coupled to the output of said audio amplifier for controlling the amplitude of an amplified noise signal;

a sound-actuated switch coupled to the output of said adjustable resistance means and comprising an operatively associated audio input transformer, rectifier diode, filter capacitor, amplifier transistor, and switching transistor for providing a logic control signal in response to the output of said audio amplifier when classroom noise exceeds a predetermined level as determined by said adjustable resistance means;

a first timing and control logic means comprising a first and second monostable multivibrator, edge detector, and logic gate, the trigger of said first monostable multivibrator and a first input terminal of said logic gate being connected to the output of said sound-actuated switch, the output of said first monostable multivibrator being connected in series with said edge detector to the trigger of said second monostable multivibrator, the output thereof being connected to a second input terminal of said logic gate, thereby preventing said logic control signal of said sound-actuated switch from being conducted through said logic gate except during a predetermined time delay of said second monostable multivibrator occuring subsequent to a prior, predetermined time delay of said first monostable multivibrator for initiating actuation of said audible alarm means only after repeated classroom noise occuring within a specified timed interval;

a second timing means, the trigger thereof being connected to the output of said logic gate of said first timing and control logic means and the output being connected to said audible alarm means for controlling actuation and duration of said audible alarm means; and

counting and readout means operatively associated with said second timing means for counting and displaying the exact number of times said audible alarm means are actuated by classroom noise, said counting and readout means further comprising a reset switch in series with reset means for resetting said counting and readout means to zero when the instructor so desires.

4. A classroom noise alarm for aiding the teacher in maintaining discipline comprising in combination:

a power supply circuit for energizing said classroom noise alarm;

a switch for actuating said power supply circuit of said classroom noise alarm;

audible alarm means;

a microphone for detecting noise occuring within a school classroom;

an audio amplifier coupled with said microphone for amplifying the output thereof;

adjustable resistance means coupled to the output of said audio amplifier for controlling the amplitude of an amplified noise signal;

a sound-actuated switch coupled to the output of said adjustable resistance means and comprising an operatively associated audio input transformer, rectifier diode, filter capacitor, amplifier transistor, and switching transistor for providing a logic control signal in response to the output of said audio amplifier when classroom noise exceeds a predetermined level as determined by said adjustable resistance means;

a noise monitor and alarm indicating means comprising a light-emitting diode connected to the output of said sound-actuated switch, said light-emitting diode being illuminated in synchronization with the output of said sound-actuated switch for visual indication of when classroom noise is of sufficient intensity to actuate said classroom noise alarm and for visual indication of when said audible alarm means are actuated;

a first timing and control logic means comprising a first and second monostable multivibrator, edge detector, and logic gate, the trigger of said first monostable multivibrator and a first input terminal of said logic gate being connected to the output of said sound-actuated switch, the output of said first monostable multivibrator being connected in series with said edge detector to the trigger of said second monostable multivibrator, the output thereof being connected to a second input terminal of said logic gate, thereby preventing said logic control signal of said sound-actuated switch from being conducted through said logic gate except during a predetermined time delay of said second monostable multivibrator occuring subsequent to a prior, predetermined time delay of said first monostable multivibrator for initiating actuation of said audible alarm means only after repeated classroom noise occuring within a specified timed interval;

a second timing means, the trigger thereof being connected to the output of said logic gate of said first timing and control logic means and the output being connected to said audible alarm means for controlling actuation and duration of said audible alarm means; and

counting and readout means operatively associated with said second timing means for counting and displaying the exact number of times said audible alarm means are actuated by classroom noise.