CN109816920A - A kind of smoke alarm using single-chip microcontroller - Google Patents

Abstract

The invention patent relates to a kind of smoke alarm using single-chip microcontroller, the functions such as sound-light alarm, automatic smoke exhausting ventilation and fire-fighting fire extinguishing are can be realized in the core devices that the present invention is designed using sensor and single-chip microcontroller as smoke alarm, cooperation other devices；Single-chip microcontroller selects AT89C51 as control device in the present invention, and sensor selects QM-N5 type gas sensor to realize the detection to smog；Smoke alarm is mainly made of smoke signal acquisition and pre-amplification circuit, analog to digital conversion circuit, single chip machine controlling circuit, display circuit, sound light alarming circuit and safety protective circuit.The present invention has rational design, is easily understood, is cheap, applies single-chip microcontroller sufficiently in the control of smog warning system, has certain practical value.

Description

A kind of smoke alarm using single-chip microcontroller

Technical field

The invention patent relates to Eletronmechanical Design Technique field more particularly to a kind of smoke alarms using single-chip microcontroller.

Background technique

Single-chip microcontroller and smoke sensor device are two big cores of smoke alarm system.Single-chip microcontroller cans be compared to a bridge, connection Sensor and warning circuit equipment.In recent years, single-chip microcontroller was gradually deeply applied to industrial and agricultural production each department and people The various aspects of life.Various types of single-chip microcontrollers also developed according to the demand of society.Single-chip microcontroller is that device level calculates Machine system, actually it is a microcontroller or microprocessor.It is small in size since it is multiple functional, it is at low cost, therefore it can To be applied in all electronic systems.Equally, it also can be widely applied to alarm technique field, make the function of all kinds of warning devices Can be more perfect, reliability greatly improves, to meet the needs of social development.And " sense of the sensor as information technology system Official " device is all difficult to form the control system of high-precision, high speed if not having " sense organ " to experience information, or " sense organ " is blunt System.The 1980s was once called the sensing technology epoch by the U.S., Japan be even more sensing technology be classified as ten big technologies it It is first.So the smoke sensor device and singlechip chip that selection is suitable, accurate, economic are to pass according to the needs of detectors Important.

AT89C51 single-chip microcontroller compatibility standard MCS-51 instruction system, powerful, the occasion for many high performance-price ratios is answered With various control fields can be flexibly applied to.QM-N5 semi-conductor gas smoke sensor device is in wider concentration range to can Combustion gas body has good sensitivity, and the service life is long, at low cost, is highly suitable for the leaking gases alarm that family uses.By this two The entire smoke alarm system that a core devices design can realize sound-light alarm, alarm condition character show, ventilation fan The due function of smoke alarms such as smoke evacuation and sprinkling fire, is that a kind of structure is simple, performance is stable, easy to use, price is low Honest and clean, intelligentized smoke alarm has certain practical value.

Currently, modern architecture all can selectively install the automatic fire alarm system of different function.Because fire is automatic Alarm system is the nervous system of building, it can experience, receive the early signal that fire occurs and and alarm, issue Alarm informs user and nearby residents simultaneously.It is like night watchman competent one by one, to inhabitation, busy or rest in family In people with the great sense of security.In the early stage of fire, accurately detects fire behavior and alarm rapidly, for timely group It is woven with sequence rapid evacuation, active and effective the sprawling for controlling fire, quick extinguishing and reduces fire to the loss of inhabitation crowd all Have great importance.

Patent of invention content

The invention patent relates to a kind of smoke alarm using single-chip microcontroller, the present invention is using sensor and single-chip microcontroller as smog report The functions such as sound-light alarm, automatic smoke exhausting ventilation and fire-fighting fire extinguishing can be realized in the core devices of alert device design, cooperation other devices； Single-chip microcontroller selects AT89C51 as control device in the present invention, and sensor selects QM-N5 type gas sensor to realize to smog Detection；Smoke alarm mainly by smoke signal acquisition and pre-amplification circuit, analog to digital conversion circuit, single chip machine controlling circuit, Display circuit, sound light alarming circuit and safety protective circuit are constituted.

The present invention has rational design, is easily understood, is cheap, fills single-chip microcontroller in the control of smog warning system Divide application, there is certain practical value.

Detailed description of the invention

Fig. 1: flammable smoke alarm system structure diagram.

Fig. 2: D.C. regulated power supply compositional block diagram.

Fig. 3: system power supply circuit diagram.

Fig. 4: clock circuit and reset circuit figure.

Fig. 5: indicator light circuit figure.

Fig. 6: sensor fault self-diagnostic circuit figure.

Fig. 7: main program flow chart.

Fig. 8: main program initialization flowchart.

Fig. 9: alarm subroutine design and flow chart.

Figure 10: keyboard scan subroutine flow chart.

Specific embodiment

In order to which the objects, technical solutions and advantages of the invention patent are more clearly understood, below in conjunction with attached drawing and implementation Example, is further elaborated the invention patent.It should be appreciated that specific embodiment described herein is only used to explain The invention patent is not intended to limit the present invention patent.

The invention patent relates to a kind of smoke alarm using single-chip microcontroller, the present invention is using sensor and single-chip microcontroller as cigarette Sound-light alarm, automatic smoke exhausting ventilation and fire-fighting fire extinguishing etc. can be realized in the core devices of fog siren design, cooperation other devices Function.

Further, single-chip microcontroller selects AT89C51 as control device in the present invention, and sensor selects QM-N5 type gas Sensor realizes the inspection to smog.

Further, smoke alarm is mainly by smoke signal acquisition and pre-amplification circuit, analog to digital conversion circuit, monolithic Machine control circuit, display circuit, sound light alarming circuit and safety protective circuit are constituted, design rationally, be easily understood, price it is low It is honest and clean, it applies single-chip microcontroller sufficiently in the control of smog warning system, there is certain practical value.

Further, smoke alarm is the smokescope being able to detect in environment, and the instrument with warning function.It should The most basic component part of alarm system should include: signal acquisition and pre-amplification circuit, analog to digital conversion circuit, single-chip microcontroller control The part such as circuit, character display circuit, sound light alarming circuit and safety protective circuit forms.The smoke alarm of design has aobvious Show the functions such as alarm condition, fault self-checking, ventilation smoke evacuation and self-extinguishing.Working method of the alarm using delay, smog inspection Alarm is surveyed using AT89C51 single-chip microcontroller as control core, selects QM-N5 semi-conductor gas smoke sensor device acquisition smokescope letter Breath, cooperation peripheral circuit constitute smog warning system.Alarm system structure is as shown in Figure 1.The work of the system is believed by smog Number acquisition and amplifying circuit convert collected smokescope information to the analog electrical signal of amplification.Analog to digital conversion circuit again will The analog signal is sent into single-chip microcontroller after being converted into the identifiable digital signal of single-chip microcontroller.Single-chip microcontroller to the digital signal at Reason, and data are analyzed to treated.When the amplified signal of input a/d converter is not zero, start warning circuit.Instead Then be normal operating conditions.Detection and monitoring for convenience, enables instrument test personnel and user to know indirectly in design Smokescope in environment, so indicating alarm condition with numeral method character.System using buzzer audible alarm and LED flashes state as alarm signal.This alarm method is that color break-up alarm is added on the basis of audible alarm.Because of variation Optical signal can cause user and family neighbours' note that limitation of the audible alarm in noisy environment is compensated for, so that report Alarm device is more perfect.While alarming starting, singlechip controller can also control to adjust valve sprinkling fire and ventilation fan Smoke evacuation movement.There are relay interfaces for system, and single-chip microcontroller is enable to control the working condition of scavenger fan and regulating valve, allow system Start associated safety feature automatically while alarm.It needs to work in a heated state additionally, due to smoke sensor device, temperature It is higher, react faster, response time and recovery time are faster.To improve the response time, guarantee sensor accurately, steadily Work, alarm need persistently to export the voltage of a 5V to smoke sensor device.In order to guarantee its reliability, in the electricity of output 5V While pressure, malfunction monitoring is carried out.When sensor heater strip or cable and sensor broken string or poor contact, failure is carried out Alarm.

Further, smoke sensor device of the invention selects QM-N5 semi-conductor gas smoke sensor device.

Further, when alarm works normally, the corresponding small voltage signal warp of the smokescope that sensor is sent Amplifying circuit amplification is crossed, A/D converter is sent into after being converted to biggish analog voltage signal, then gives AT89C51 monolithic again Machine processing.When single-chip microcontroller detects that the amplified signal for inputting ADC0809 is not zero, system starting alarm.When alarm, LED is red 60min, buzzer starting and the 60min that persistently pipes are lighted and continued to flash to lamp, and LED charactrons show symbol " 1 ", and take a breath Automatic running is fanned, to achieve the purpose that improve the air quality in environment.Meanwhile if tap water or family's water storage pipeline have water, Then single-chip microcontroller calls time delay subroutine, controls to adjust valve progress sprinkling fire by relay by single-chip microcontroller through delay 600s and moves Make.Otherwise, alarm system can only start sound-light alarm and ventilation fan automatic smoke exhausting function and can not carry out extinguishing action.Conversely, Alarm does not sound an alarm, and LED state indicator light green light is always on and does not flash, and charactron does not show that character, buzzer do not issue The sound.In order to distinguish the alarm normally to work, in false alarm and abnormal working condition alarm, LED charactrons are shown Symbol " 0 ", buzzer audible alarm continues 30min, while 30min is lighted and flashed to LED amber light, to remind user to check sensing Device or circuit connection situation are debugged in time, guarantee safety.In addition, system is additionally provided with the key of a silencing function, when When alarm sending pipes, user reaches scene, can press the button (ventil) stop alarm device and pipe.If it is dense to spend some time Degree still exceeds alarm limit, and alarm can pipe again and remind user.

Further, compositional block diagram of the invention is as shown in Figure 2.The effect of power transformer is to change the exchange of power grid The alternating current of 220V, 50Hz are depressured by the size of voltage, and the alternating voltage for exporting the secondary side of transformer, which meets design, to be wanted It asks.Alternating voltage is transformed to unidirectional pulsed dc voltage, recycles capacitor by the one-way conduction for then utilizing diode Big DC voltage of pulsing is processed into the small DC voltage of smooth pulsation by the filter circuit of energy-storage travelling wave tube composition, i.e., will be whole Alternating component in the pulsating dc voltage of current circuit output filters, and leaves behind smoother DC voltage, finally utilizes collection At voltage-stablizer W7805, the output voltage stabilization of power circuit is allowed to be 5V, in this, as the power supply of system various pieces circuit.This Power circuit diagram used by inventing is as shown in Figure 3.

Further, an oscillator being made of sign-changing amplifier, XTAL1 are equipped with inside AT89C51 singlechip chip It is respectively the input terminal and output end of oscillating circuit with XTAL2, clock can be drawn by internal or external generation in XTAL1 and XTAL2 External crystal oscillator Y, internal oscillator circuit will generate self-oscillation on foot.The timing element that system uses is quartz crystal With the shunt-resonant circuit of capacitor composition.Crystal oscillator frequency selects 12MHZ, and the capacitance of C1, C2 take 30pF, and the size of capacitor plays frequency The effect of rate fine tuning.Clock circuit is as shown in Figure 4.

Further, the present invention uses operational amplifier of the LM324 as circuit.LM324 is cheap with differential The high-gain four-operational amplifier of input function.The quiescent dissipation of LM324 is small, cheap, can be in compared with wide-voltage range It works under single supply or dual power supply, source current very little and unrelated with supply voltage, four amplifier consistency are good；It inputs inclined Leakage resistance is temperature-compensating, is also not required to external frequency compensation, can accomplish that output level is compatible with digital circuit.

Further, circuit connect to reach control with the port single-chip microcontroller P2.3 by transistor base one resistance of series winding Whether buzzer processed alarms.System is equipped with a noise reduction key, and when alarm sending pipes, user reaches scene, can press Noise reduction key stop alarm device pipes.If crossing some time-concentrations still exceeds alarm limit, alarm can pipe again and remind user.

Further, state instruction circuit for lamp is as shown in figure 5, green light is always on expression normal condition, flammable smog in environment Concentration is extremely low；Amber light flashing indicates that sensor connecting fault or wiring circuit contact are bad；Blinking red lamp indicates that smog is dense in environment Degree is more than alarm minimum predetermined value, and user is reminded to make corresponding safe precaution measure as early as possible.

Further, in safety protective circuit, whether relay (electromagnetic relay), which acts, is whether protection act is held Capable unique conditional.When the live smokescope being detected reaches alarm preset value set by setter, relay KA1 movement, automatic air-exchanging starting fan.At this point, single-chip microcontroller calls time delay subroutine, after the 600s that be delayed, relay KA2 is moved Make, regulating valve opens fire extinguishing water simultaneously.The working principle of relay is to control high pressure working using low-voltage control circuit Road.In the input circuit of relay, when the curent change of flowing through coil, coil can generate self-excitation voltage to inhibit electric current Change, the curent change in coil is faster, and generated voltage is higher.So in the design, when MCU driving relay, need A diode in parallel is wanted, reaches ballast coil voltage and guarantor using the reverse breakdown capability of diode to eliminate self-excitation voltage Protect the purpose of transistor.When transistor C8550 becomes cut-off from being connected, the electric current for flowing through relay coil will be reduced rapidly, At this moment coil can generate two interpolar of c, e that transistor is added in after very high self induction electromotive force is superimposed with supply voltage, can make crystal Pipe breakdown, in relay parallel connection after diode, can by the self induction electromotive force clamper of coil in the forward conduction voltage of diode, To avoid breakdown transistors.It is certain it is noted that the polarity of diode can not be reversed when parallel diode, otherwise it is easily damaged crystalline substance Body pipe etc. drives component.

Further, alarm self-diagnosis of trouble deenergizing as shown in fig. 6, sensor ground terminal connect a resistance R16. When sensor normally connects, resistance and sensor partial pressure, there is faint voltage at resistance both ends at this time, and single-chip microcontroller can pass through The IN2 mouth of ADC0809 detects；If probe power malunion is normal, open circuit can be generated, detects resistance both end voltage It is 0.Another situation is that judging whether sensor signal end connects correctly, additional circuit is not needed at this time, preheats 1 in sensor After~2 minutes, it is connect by the IN1 input port with ADC0809, the output voltage of measurement sensor signal, if voltage is 5V then illustrates that the signal end malunion of sensor is normal, and system sounds an alarm at this time.

Further, the main program flow chart that this hair has is as shown in Figure 7.It first has to preheat to sensor, because of QM-N5 type Semiconductor resistance-type smoke sensor device is after no power stores a period of time, and when being once again powered up, sensor cannot be adopted normally immediately Collect smog information, a period of time is needed to preheat.After program initialization, system enters monitor state.Program design is first right Sensor preheating, preheating carries out fault detection simultaneously, to sensor, using software mode detection sensor heater strip or cable Whether break or poor contact.In the work of entire alarm system, the smog that AT89C51 single-chip microcontroller detects sensor is dense After spending signal progress signal amplification, A/D conversion process, it is analyzed and processed by single-chip microcontroller, judges whether system starts acousto-optic report It is alert.Main program further includes eight segmentation charactron concentration character display function of LED, noise reduction keypress function, safety linkage device, is interrupted Subprogram etc. keeps detectors more perfect, brings advantage to the user.

Further, main program initialization flowchart is as shown in Figure 8.After sensor preheating, program starts to execute initial Subroutine, the function that this part is realized include that setting, initialization of register, the interruption of various I/O mouthfuls of input/output states make Energy is equal.

Further, subroutine design and flow chart are alarmed as shown in figure 9, when amplified signal is not zero, i.e. cigarette Mistiness degree reaches the alarm preset value of system, and alarm issues a kind of tweeting sound of approximate siren at this time, corresponding output channel Red lamp flass, ventilation fan automatic running, and Time Delay Opening regulating valve.To prevent from reporting by mistake, in programming, to smokescope It carries out quickly repeating detection and delayed alarm, to distinguish the leakage for being smog in pipeline, or since opening valve of short duration produces The micro of raw flammable smog scatters and disappears, and prevents from reporting by mistake.

Further, this alarm designs adds a silencing function key.Key is being closed due to the influence of elastic reaction Closing and disconnecting has dither process, to make voltage also shake, so to eliminate the influence of shake in key range.It presses The recognition methods of key uses scanning method, and keystroke handling program flow diagram is as shown in Figure 10.

The above description is only a preferred embodiment of the patent of the present invention, is not intended to limit the invention patent, all at this Made any modifications, equivalent replacements, and improvements etc., should be included in the invention patent within the spirit and principle of patent of invention Protection scope within.

Claims (3)

1. the core devices that the present invention is designed using sensor and single-chip microcontroller as smoke alarm, cooperation other devices be can be realized The functions such as sound-light alarm, automatic smoke exhausting ventilation and fire-fighting fire extinguishing.

2. a kind of smoke alarm using single-chip microcontroller according to claim 1, which is characterized in that single-chip microcontroller in the present invention Select AT89C51 as control device, sensor selects QM-N5 type gas sensor to realize the detection to smog.

3. a kind of smoke alarm using single-chip microcontroller according to claim 1, which is characterized in that the present invention is mainly by cigarette Fog signal acquisition and pre-amplification circuit, analog to digital conversion circuit, single chip machine controlling circuit, display circuit, sound light alarming circuit and Safety protective circuit is constituted.