单片机的红外语音报警系统

悉尼Assignment代写范文:“单片机的红外语音报警系统”，这篇论主要描述的是以驾驶电机车为例，在遇到危险的时候，司机单凭感觉是无法做出正确的反应，因此我们需要对电机车安全性问题进行分析和研究，采用单片机的技术，通过在传感器技术发出声音来做出警报，这样就能够实现语音报警的功能，让电机车司机能够有充足的时间做出反应。

1. Introduction

Mine electric locomotives mainly used for underground main haulage roadway and ground transportation over long distances. Equivalent electric locomotives in railway transport, vehicles towing by car or train on the tracks walks, the completion of coal, waste, material, equipment, and personnel movement. Motor car should be checked before the bolt is loose, insulated electrical components are good, the handle is flexible. Check for any abnormal situation, train signal to warn nearby personnel. Desired direction, operations controller of the reversing handle to determine orientation of locomotive. Operating speed on the controller handle, given the slow speed, complete the boot process. Motor cars on the road, at any time according to the road gradient and speed the production and transportation. Speed, operating speed on the controller handle to speed up or slow down the direction, until the desired speed. In the governing process, should observe the road conditions ahead and pedestrian conditions, and prevent the occurrence of accidents.

Current stop-start brakes drive of mine electric locomotive to locomotive during driver's eye they find, further braking, to prevent accidents from happening. When electric locomotives the driver is tired or distracted when pure eye, still possible accidents. Main topic of mine electric locomotives by infrared detection, voice alarm solutions to their problems in mine safety. This alarm with Pyroelectric infrared sensor probes, non-contact distance measurement, sensing infrared converted into voltage signals, through single chip processing, complete voice alarm. When someone in the motor vehicle lane when the sound alarm to remind passers-by away, drivers speed brakes to ensure the safety of passers-by, and reduce the occurrence of accidents.

2. Overall system design

This system is based on Pyroelectric infrared Intelligent detection of passive warning devices. As passers-by the infrared radiation through a Fresnel lens was focused on Pyroelectric infrared sensor to detect when the Pyroelectric infrared sensor's output voltage and the amplified signal amplification circuit, and into the infrared sensor signal processor, treated to the microcontroller output high. Controlled by single-chip audio chip sound alert passers-by and locomotive drivers. System consists of an infrared acquisition module, signal processing modules, MCU, voice control module alarm module.

Devices used in each module and function as follows:

(1) IR module: infrared detection circuit is implemented by a Pyroelectric infrared probe P288. It combines data acquisition, a/d conversion, the comparison judging functions integrated into one.

(2) signal processing module: due to hot release electric infrared sensor output of detection signal voltage is weak (usually only has 1mV around), and is a changes of signal, while Philip Fresnel lens of role and makes output signal voltage is pulse form (pulse voltage of frequency by was measuring objects of mobile speed decided, usually for 0.1~10Hz around), so should hot release electric infrared sensor output of voltage signal for Zoom. Amplified signal on the control before they are processed into single chip, using special infrared sensor signal processor BIS001 pretreatment for use by the microcontroller.

(3) the MCU Module: MCU control is realized by SCM. It is the heart of the whole system, which receives alarm signals and control and coordinate all functions module to work properly.

(4) the alarm module: speech circuit United States ISD's integrated high fidelity recording and playback of voice chip ISD1420 and some resistance, capacitance, and speakers to complete the voice alarm.

3. Hardware design of system

3.1 IR acquisition and signal process module design

3.1.1 infrared sensor selection

The design of Pyroelectric infrared sensor P288, the d-side of the sensor to supply cathode, g Terminal power supply negative, s Terminal for signal output. Pyroelectric infrared sensor P288 external 12V power supply inside with Fresnel lenses and detection area are spherical, effective alert distance up to 15m, direction angle of 85 °.

3.1.2 signal amplifying circuit design

Due to hot release electric infrared sensor output of detection signal voltage is weak (usually only has 1mV around), and is a changes of signal, while Philip Fresnel lens of role and makes output signal voltage is pulse form (pulse voltage of frequency by was measuring objects of mobile speed decided, usually for 0.1~10Hz around), so should hot release electric infrared sensor output of voltage signal for Zoom. After general integrated operational amplifier LM324 enough gain after two-stage, the output signal to the infrared sensor signal processor circuits. Before the signal amplifier, first by P288 output voltage of the sensor signal through a resistor-capacitor band-pass filter, the upper cut-off frequency of the filter is 16Hz, the lower cut-off frequency is 0.16Hz.

3.1.3 BIS001 infrared sensor signal processing circuit design

Signal amplifier outgoing infrared sensor signal processor in BIS001 signal amplifier after OP1 preamplifier, OP2 capacitively coupled to the operational amplifier two-stage, and then via a voltage comparator COP1 and COP2 two-way amplitude after processing, check out effective trigger signal to start the delay timer. Output signals via transistor Q1 followed by single-chip microcomputer for their reading.

3.2MCU control module design

In this design, we will use the ATMEL company AT89S51.

12MHz quartz crystal clock circuits, taking into account the size of the capacitors C1 and C2 will slightly affect the oscillator frequency of high and low, oscillator, stability, ease of vibration and temperature stability, 30PF.

Reset circuit composed of resistors, capacitors and switch, and a power-on reset and manual reset function. SCM INT0 and infrared sensor signal processor BIS001 output voltage signals connected to the O2. Voice P0.0~P0.5 ISD1420 v/PLAYL A2~A7,P0.6 ISD1420 voice of chip the chip, active low.

3.3 voice alarm circuit design

The voice chip used in the design of ISD1420 voice recording chip.

3.3.1 ISD1420 principle

In the process of recording, ISD1420 before the store operation, in several stages to adjust the signal. First zoom in to memory the best dynamic range of the input signal level, this stage is composed of pre amplifier, amplifier with automatic gain control to complete.

Preamplifier by across DC capacitors connected to the microphone connector across DC capacitors used to remove small signal AC DC component (approximately 2mV~20mV). Signal amplification in two steps, first input preamplifier, and then fixed-gain amplifiers. Signal pathways in the analog output (ANAOUT) and analog inputs (ANAIN) connect a capacitor between the two pins. Dynamic monitoring of automatic gain control circuit the amplifier's output signal level and gain control voltage is sent to the preamplifier. Preamp gain automatically adjusts to maintain filter the signal for the best level so that recording can get the highest level of signal to minimize clipping. You can choose to connect to pin AGC resistor and capacitor values to adjust the description automatically gain circuit characteristics of two time constants, namely, response time, and release time.

The next phase of the signal conditioning is done by the input filter. Because storage is the use of sampling techniques for analog signals, so it needs an anti-alias filter to remove (or at least reduced to a negligible level) sampling frequency input frequencies in excess of 1/2. This meets the law of all data acquisition systems follow the Nyquist sampling. Sound quality of the voice quality to be superior to telephone sampling frequency to 8KHz. The high frequency of the low pass filter options in the 3.4KHz, may satisfy the Nyquist sampling laws, but there is still a wide enough bandwidth to get high-quality voice. Continuous-time five-pole low pass filter is a filter in the 3.4kHZ 40dB per octave attenuation.

Signal when the adjustment is complete, to write the input waveform simulates the transceiver in simulated storage array. By 8KHz sampling clock sampling, and level of nonvolatile write processes needed to shift high-voltage and compensation associated with FowlerNordheim tunneling effect of practical factors. Sampling clock is also used to store the address of the array decoding in order to write to the storage array in the order of the input signal.

When the playback, analog voltage that can be recorded in sequence under the control of the sampling clock to read out from the storage array, back into the original sampled waveforms. Smoothing filter remove the sampling frequency of the output channels and restores the original waveform smoothing filter output through an analog multiplexer is connected to output amplifiers, two output pins directly drive loudspeakers.

3.3.2 ISD1420 peripheral circuit design

Are single-ended, and speaker coupling capacitor on the output side. Recording using prior recording mode, press k press recording began, RECLED pin port is set to a low level, and light emitting diode LED is lit, prompted the recording began, when the recording is finished, LED is off. Recording content for cars, please stay away from Lane, directly from the MIC1 input, MIC and MICREF pins enter the amplifier chip, amplified output signal output from the analog output of ANA OUT, and then by 0.1uf capacitor coupled to the analog input again ANA IN amplifier, amplify the audio signal output from SP+ to promote speakers pronounce. ISD1420 voice chip P0 P0.0~P0.5,/PLAYL A2~A7 single chip microcontroller P0.6, active low, control the playback time. Once you start playback, stop delay 10s, wait for the next/PLAYL to 0 o'clock playback again.

For ISD1420 driving capability is limited (0.5W), directly to the speaker is not very ideal, if more than 1W speaker distortion will occur. Usually below 1 w speaker with LM386, D2822, MC34119 and TA368 chip-driven. 1W~10W speakers with TDA2003, LA4440 drive.

In this design, with a view to sound speaker volume is large enough to remind locomotive drivers, pedestrians.

When in some cases the required speaker power is high, joins the circuit can be used, can achieve a high ringing sound effects.

3.4 power module design

Mine electric locomotives can be classified by their working power source overhead line electric locomotive and battery electric locomotive. For motor vehicles provided traction power supply is DC, overhead line voltage for electric locomotive 250V~120V, battery electric locomotive about 110V voltage.

3.4.1 system power analysis

This involved designing the operating voltage of the device.

From analysis to know the system operating voltage set in the 12V and 5V, motor vehicle working voltage of about 110DCV~250DCV.

3.4.2 the choice of switching power supply

From switch power transform voltage before and after straight Exchange can is divided into AC/DC and DC/DC two big class, DC/DC transform device now has achieved module of, and design technology and the production process in both at home and abroad are has mature and standardization, and has get user of recognized, but AC/DC of module of, for its itself of characteristics makes in module of of process in the, encountered more complex of technology and process manufacturing problem. Everything from stringing electric locomotive to battery electric locomotive, is provided by DC, you can provide power supply to the system is direct current, since only use switching power supplies DC/DC converters.

Design of Shenyang new Sun technology limited Corporation of power equipment products of industrial and mineral electrical locomotive power, so that can be obtained from the traction power or battery voltage 12V system power supply. LM2575 this design can be used to convert 12V to 5V systems.

LM2575 when designing a circuit, the following points should be noted:

(1) inductance should be chosen according to the maximum output voltage level, input voltage (MAX), the maximum load current (MAX) parameters such as inductance.

(2) input/output the input capacitance of the capacitor should be greater than 47 μ f, and close to the circuit. While the output capacitance of the capacitor is recommended for 100 μ F-470 μ f, the pressure value should be greater than 1.5 to twice times the rated output. For 5V voltage output, recommended voltage of 16V capacitor.

(3) the diode is rated current of the diode should be greater than 1.2 times times the maximum load current, but taking into account the load short-circuit conditions, value should be greater than the rated current of the diode LM2575 maximum current limit of diode reverse voltage maximum input voltage should be greater than 1.25 times.

4. system software design

MCU AT89S51 receive signals from the infrared sensor break, start a voice chip ISD1420 alarm.

5. System anti-interference measures

The system used in mine electric locomotive, poor working environment in underground, vulnerable to various noise violations. According to different sources, there are spatial (through electromagnetic radiation into), channel interference (connected to the automatic alarm through the forward and backward access), the power supply system of interference as well as interference between PCB and circuit. So in the design, should take the necessary measures, exemptions and reduce the effects of various negative factors and damage, so as to improve the stability and reliability of the system.

The system hardware design process, mainly consider the following hardware-related measures to improve anti-jamming ability:

(1) for space radiation interference suppression, the main solution is to shield. Shielding conductor material. For the purposes of electromagnetic shielding, control system can be installed inside the closed chassis made of iron, to shield external electrostatic and electromagnetic interference.

(2) when you design a printed circuit board, reasonable layout, in order to make each component in the system, between circuits limit possible adverse effects to a minimum:

Element arrangement and signal alignment as far as possible in order, straight short, simple, to avoid interaction between adjacent circuit.

Try to avoid long parallel alignment, reducing wiring capacitance.

Grounding resistance of grounding widened so as to reduce as far as possible, and solve the problem of grounding.

Avoid a loop accepts printed circuit noise interference.

(3) power supply design strength of strict separation, not design them on a circuit board, power cord is going as much as possible consistent with the direction of the data transfer. In key parts of the printed circuit board configurations to coupling capacitance, power input jumper 10pF capacitor. Each IC and 0.01pF high frequency capacitor on the power supply pins. For anti-noise ability, turn-off current device or when integrated, should be in the chip's power cord (VCC) and ground (GND) direct access to the 0.01pF the decoupling capacitor.

(4) input not in use do not allow dangling in the circuit, it will cause a logic level is not normal. According to the actual situation, the extra input and is connected to the power supply or. Practice shows that the components of quality has a great effect on the system. Genuine components should be selected. Also it is necessary to filter before using. For connectors, you should choose good seismic behavior, engage reliable, locking connectors.

In addition, because the system used in switching power supply, taking into account the switching power supply electromagnetic compatibility problems. Electromagnetic compatibility of the solution: speak from the three elements of electromagnetic compatibility, electromagnetic compatibility problem you want to solve the switching power supply, from three aspects: first, to reduce sources of disturbance signals; second, cut off disturbance signal transmission; and, third, harassed enhanced ability to resist harassment. In resolving the internal switching power supply compatibility issues, utilization of the above three methods, on the premise that cost-benefit ratio and ease of implementation. Thus, switching power supply of external disturbance, such as power line harmonic currents, power-line transmission harassment, harassment can only be used to reduce electromagnetic radiation sources to address. On one hand, can enhance the design of input/output filtering, improving the performance of APFC circuit, reduce the switch and rectifier, freewheeling diode voltage and current change rate, using a variety of soft-switching circuit topology and control method on the other, strengthen case shielding effectiveness, improving the chassis slot leakage, and good ground handling. Resistance to external harassment (such as surges, lightning strikes) should optimize the AC input and DC output port of lightning. Usually, 1.2/50 open circuit voltage and short-circuit current 8/20 a combination of lightning wave energy is small, usually with zinc oxide Varistors and gas pipes and other combinations of methods to deal with it. Electrostatic discharge, usually in the communication port and control port in the small-signal circuit, use of TVS and the corresponding ground protection, increased small-signal circuit with the chassis, such as the distance to resolving or components selected for their antistatic harassment. Contains a wide spectrum of fast transient signals easily with common-mode control circuit for incoming, using static the same way and reduce the common-mode inductance distributed capacitance, strengthening the common-mode signal input circuit (with common mode capacitor or insertion loss ferrite rings) to increase the immunity system.

Reduced switch power of internal harassment, achieved its itself of electromagnetic compatible sex, improve switch power of stability and the reliability, from following several aspects starts with: ① note digital circuit and module circuit PCB wiring of right partition; II digital circuit and simulation circuit power of to coupling; ③ digital circuit and simulation circuit single points grounding, and big current circuit and small current especially current voltage sampling circuit of single points grounding to reduced total resistance harassment, reduced to ring to effect, wiring Shi note adjacent line between of spacing and the signal nature, To avoid crosstalk, reduced the rectifier circuit and continued flow diode circuit with filter area surrounded by a tributary, reduce leakage, inductance distributed capacitance of the transformer using high resonant frequency filter capacitor, etc.

6. Summary

Infrared voice alarm system based on the AT89S51 microcontroller basically completed its intended function. The system is feasible and realistic significance.

51due留学教育原创版权郑重声明：原创留学生作业代写范文源自编辑创作，未经官方许可，网站谢绝转载。对于侵权行为，未经同意的情况下，51Due有权追究法律责任。

51due为留学生提供最好的悉尼Assignment代写服务，亲们可以进入主页了解和获取更多assignment代写范文 提供美国作业代写服务，详情可以咨询我们的客服QQ:800020041哟。-xz