CN201922865U

CN201922865U - Tire pressure monitoring system based on AT89S51 singlechip

Info

Publication number: CN201922865U
Application number: CN2011200559506U
Authority: CN
Inventors: 李卓; 刘斌
Original assignee: Northeast Petroleum University
Current assignee: Northeast Petroleum University
Priority date: 2011-03-06
Filing date: 2011-03-06
Publication date: 2011-08-10
Anticipated expiration: 2021-03-06

Abstract

The utility model relates to a tire pressure monitoring system based on an AT89S51 singlechip, which mainly solves the problems of complicated system, high production cost and popularization difficulty of the existing tire pressure indirect detection system. The tire pressure monitoring system is characterized in that the system also comprises a DF data wireless transmitting module, a DF data wireless receiving module, a signal amplifier, an analog to digital (A/D) converter and the AT89S51 singlechip, wherein a pressure sensor outputs detected tire pressure signals to the DF data wireless transmitting module, the DF data wireless receiving module receives the tire pressure signals and outputs the tire pressure signals to the signal amplifier, output corresponding amplifying signals are input to the signal input end of the AT89S51 singlechip after being converted into digital signals by the A/D converter, and the AT89S51 singlechip outputs display signals to a light emitting diode (LED) digital display screen after processing the detected tire pressure signals. The tire pressure monitoring system can realize the intellectualization of the tire pressure monitoring, in addition, the structure is simple, the production cost is greatly reduced, and the popularization and the application are convenient.

Description

A kind of tire pressure monitoring system based on the AT89S51 micro controller system

Technical field

The utility model relates to a kind of detecting device of air pressure of automobile tire, specifically, relates to a kind of device that tire pressure is detected in real time can realized.

Background technology

The air pressure of automobile tire monitoring system mainly is divided into indirect type tire pressure monitoring system and direct-type tire pressure monitoring system at present.These two kinds of prior aries are when the detection wheel air pressure, all there are some problems separately, narration respectively below: the indirect type system for monitoring pressure in tyre is to be equipped with on the automobile of ABS, by analysis to tire vibration or tire radius, whether the inflation pressure that indirect detection goes out tire surpasses alarm limit, thereby whether decision needs to report to the police.The advantage of this system is that durability is strong, reliability is high, does not need battery, does not also have the problem that is subjected to radio wave interference, does not need the street rod tire, and cost is lower.But its defective is: can not show the instantaneous accurately atmospheric pressure value of each tire; When same axletree or the same side wheel or 4 tire pressures descend simultaneously, can not report to the police; Can not take into account the layout and the type of drive of the speed of a motor vehicle, monitoring accuracy and driving engine simultaneously; Reaction time is grown and can not the failure judgement tire location.Therefore this system is difficult to adapt to the needs that tire pressure of automobile tire detects at present.The direct-type system for monitoring pressure in tyre is that to utilize what be installed in that each takes turns tyre cavity be that the pressure sensor of power supply comes direct measuring pulley air pressure with the lithium ion battery, and testing result is transmitted on the monitoring device that is installed in operator platform by wireless-modulated.Monitoring device shows each tire pressure at any time, and the driver can understand the air pressure situation of each tire intuitively.Too low or when seepage was arranged, system can auto alarm when tire pressure.The advantage of this type systematic is conspicuous, and market outlook are also very good, but conventional device constitutes comparatively complexity, and cost is higher, so field of application is less.

Summary of the invention

In order to solve the problems of the prior art that background technology proposes, the utility model provides a kind of tire pressure monitoring system based on the AT89S51 micro controller system, this kind tire pressure monitoring system can be realized the intellectuality of tire air pressure monitoring, and it is simple in structure, greatly reduce productive costs, easy to utilize.

The technical solution of the utility model is: this kind is based on the tire pressure monitoring system of AT89S51 micro controller system, comprise pressure sensor, LED digital display screen and warning circuit, in addition, described tire pressure monitoring system also comprises DF data wireless transmitter module, DF data wireless receiver module, signal amplifier, A/D converter and AT89S51 micro controller system; Wherein, described pressure sensor is exported detected tire pressure signal to described DF data wireless transmitter module, described DF data wireless receiver module receives the aforesaid tyre pressure signal and exports it to signal amplifier, and the corresponding amplifying signal of output is input to the signal input part of described AT89S51 micro controller system after A/D converter converts digital signal to; Described AT89S51 micro controller system is handled the back to described LED digital display screen output shows signal with the tire pressure signal that records.

During concrete enforcement, described pressure sensor is a NPP301-700A type silicon pressure sensor, and described signal amplifier adopts two-stage LM358 chip to constitute, and described A/D converter adopts the ADC0809 chip.

The utlity model has following beneficial effect: native system adopts silicon pressure sensor NPP301-100 as the tire pressure detecting element, convert tire pressure signal to voltage signal, this voltage signal is very faint, after the transmission through wireless transmitter module and receiver module, amplifying the back by op amp LM358 forms stronger voltage signal and is transferred to and is converted to digital signal among the ADC0809, by the AT89S51 micro controller system data that obtain are handled again, send into the display part at last and carry out number and show, simultaneously when hypotony or too high will be by the warning circuit alarm.In the native system circuit structure simple, be easy to debugging and safeguard, and low price, easy to utilize.In addition, it has the characteristics of integrated digitalization, and measured error is little, can satisfy the needs of most actual monitoring system.

Description of drawings

Fig. 1 is a theory of constitution block diagram of the present utility model.

Fig. 2 is the electrical schematic diagram of micro controller system described in the utility model specific embodiment.

Fig. 3 is the electrical schematic diagram of LED digital display screen and driving circuit thereof in the utility model specific embodiment.

Fig. 4 is the electrical schematic diagram of warning circuit in the utility model specific embodiment.

Fig. 5 is the electrical schematic diagram of signal amplifier circuit in the utility model specific embodiment.

Fig. 6 is the frequency dividing circuit electrical schematic diagram that is made of double D trigger SUN7474 that produces the 500kHz clock signal in the utility model specific embodiment for A/D converter.

Fig. 7 is the electrical schematic diagram of A/D converter in the utility model specific embodiment.

Fig. 8 is the electrical schematic diagram of pressure sensor in the utility model specific embodiment.

Fig. 9 is the electrical schematic diagram of the utility model specific embodiment as the USB feed circuit of power input.

The specific embodiment

The utility model is described in further detail below in conjunction with accompanying drawing:

By shown in Figure 1, this kind is based on the tire pressure monitoring system of AT89S51 micro controller system, comprise conventional component units such as pressure sensor, LED digital display screen and warning circuit, its unique distinction is: also comprise DF data wireless transmitter module, DF data wireless receiver module, signal amplifier, A/D converter and AT89S51 micro controller system in the described tire pressure monitoring system; Wherein, described pressure sensor is exported detected tire pressure signal to described DF data wireless transmitter module, described DF data wireless receiver module receives the aforesaid tyre pressure signal and exports it to signal amplifier, and the corresponding amplifying signal of output is input to the signal input part of described AT89S51 micro controller system after A/D converter converts digital signal to; Described AT89S51 micro controller system is handled the back to described LED digital display screen output shows signal with the tire pressure signal that records.

Provide the specific embodiment of an optimization below: described pressure sensor is a NPP301-700A type silicon pressure sensor, converts tire pressure signal to voltage signal, and its electrical schematic diagram as shown in Figure 8.Consider that this voltage signal is very faint, therefore described signal amplifier adopts two-stage LM358 chip to constitute, as shown in Figure 5.And described A/D converter adopts the ADC0809 chip, as shown in Figure 7, because its requirement is provided at the clock signal that inserts 500kHz on its CLK pin, select for use double D trigger SUN7474 that the clock signal on the ALE pin of micro controller system is carried out the clock signal that frequency conversion obtains 500kHz, the electrical schematic diagram of double D trigger SUN7474 as shown in Figure 6 for this reason.

Described wireless transmitter module is selected the DF data module, the DF data module adopts the ASK mode to modulate, to reduce power consumption, transmitter current reduces to zero when data-signal stops, data-signal and DF transmitter module input end can be with resistance or direct connections and can not be used capacitive coupling, otherwise the DF transmitter module is with cisco unity malfunction.Data level should be near the real work voltage of DF data module, to obtain higher modulation effect.The DF transmitter module is vertically mounted on the lateral wall of tire inner tube, should leave more than the peripheral devices 5mm, to avoid parameter of distribution shadow noon.The transmission distance of DF module and Tiao system Xin Frequency leads and the sensitivity and the transmitting-receiving environment of amplitude, emission voltage and capacity of cell, emitting antenna, receiver are relevant.Generally about 800 meters at the open area maximum launch range, having under the situation of obstacle, distance can shorten, because refraction in the radio signal transmission process and reflection can form some dead bands and unstable region, different transmitting-receiving environment have different reception and transmission ranges.

The concrete working process of native system is as follows:

At first, finish the initialization of ADC0809 and read its transformation result.The OE leg signal is changed to 0, gives positive pulse signal of ST then, start the A/D conversion.In hardware connection, determined the zone bit that converts of ADC0809 has been received on the P3.2 mouth of AT89S51, so only need to judge that the value of position P3.2 is promptly changed as can be known whether finishes.When converting, it is data on the readable data passage that OE is put 1.

Secondly, carry out conversion to the signal that micro controller system reads in to obtain the tire real-time pressure.Because the signal of sensor output inserts A/D through amplifying, so need this with the A/D transformation result that reads divided by magnification factor, can get the size of the cooresponding pressure of this result again according to the output of the relation of the output of sensor and input and A/D conversion and the relation of input, get final product the real-time pressure size of proper front tyre by above computing.

Once more, the pressure signal that conversion be obtained is delivered to charactron and is shown, as shown in Figure 3.In the design, adopt dynamically digital 48 hop count sign indicating numbers of the method design-calculated display module that shows, in procedure for displaying, use the mode of timer periodic refreshing in addition, refresh data presented on the bits per inch sign indicating number pipe one by one by the sheet choosing.As long as it is suitable that the time that timer interrupts is provided with, at naked eyes, the demonstration of charactron is exactly continuous.Such design helps saving the pin resource of micro controller system, designs easy.In addition, this programme adopts 4 the 8 sections integrated charactrons that are total to anode, can reduce the number of, lines on the pcb board, the integrated level of enhanced system.

At last, the prompt functions in the time of finishing the tire pressure mal.Because the driving circuit that adopts simple buzzer phone in the present embodiment is as warning circuit,, only need on the pin that buzzer phone connect, output low level can make buzzer phone produce alerting signal so its software design is also very simple.

In the design of power module, for improving power-efficient and simple and practical, adopt the USB power supply mode in this example, as shown in Figure 9, this design makes shortcomings such as the more convenient and very big watt loss that produces when having avoided adopting alternating current 220V in the tradition of the acquisition of power supply, chip heating, interference.

In sum, the circuit in the native system is realized making simply easily, and low price, and it is dispersed big to have overcome the employing discrete component, is not easy to the shortcoming of integrated digitalization.Simultaneously, index easy to adjust, that can take into account is many, and the most important thing is that its measured error is little, can satisfy the needs of most actual monitoring system.

Claims

1. tire pressure monitoring system based on the AT89S51 micro controller system, comprise pressure sensor, LED digital display screen and warning circuit, it is characterized in that: described tire pressure monitoring system also comprises DF data wireless transmitter module, DF data wireless receiver module, signal amplifier, A/D converter and AT89S51 micro controller system; Wherein, described pressure sensor is exported detected tire pressure signal to described DF data wireless transmitter module, described DF data wireless receiver module receives the aforesaid tyre pressure signal and exports it to signal amplifier, and the corresponding amplifying signal of output is input to the signal input part of described AT89S51 micro controller system after A/D converter converts digital signal to; Described AT89S51 micro controller system is handled the back to described LED digital display screen output shows signal with the tire pressure signal that records.

2. a kind of tire pressure monitoring system according to claim 1 based on the AT89S51 micro controller system, it is characterized in that: described pressure sensor is a NPP301-700A type silicon pressure sensor, described signal amplifier adopts two-stage LM358 chip to constitute, and described A/D converter adopts the ADC0809 chip.