1、1 Ratemeter and monolithic integrated circuit The traditional automobile rotational speed odometers function has two； first, with indicator instruction automobile travel instantaneous vehicle speed； second, records the automobile travel with the mechanical counter the accumulation course. The modern
2、 automobile is developing to the high speed direction, along with the vehicle speed enhancement, the tradition speedometer which actuates with the flexible axle receives the unprecedented challenge, this is because of the flexible axle when high speed revolving, as a result of steel wire alternate s
3、tresses limit limit, but easy to break, simultaneously, the flexible axle will arrange long will have presented the deformation oversized or the movement sluggish and so on phenomena, moreover, regarding the different vehicle type, the rotational speed odometers installment position will also receiv
4、e the flexible axle length and bending limit. All these, causes based on the non-contact type tachometer generators electronic formula rotational speed odometer to be able the rapidly expand. Presents automobile measuring appliance automaticity is very high, what the old style mechanical flexible ax
5、le transmissions measuring appliance already eliminated displaces is presents liquid crystal gauge board, is impossible through to dial the digital code wheel adjustment odometer again. When in the driver needs to increase the number of passes, runs the table with this kind to be possible very with
6、ease to realize. This kind runs the table use medium scale integration design to become, the volume is exquisite, the movement is stable, is suitable uses on each kind of electronic transducers automobile. This kind of exquisite instrument has compared to the other similar products obvious merit: 1s
7、t, the circuit design is exquisite, strict. Has used the high performance integrated circuit and the electronic component, the guarantee circuit has the high quality； The use optimizations circuit design, considered many disadvantageous use environment, enable the instrument as far as possible in th
8、e voltage, the temperature, the humidity, the dust pollution and so on under complex change factor many conditions to be able the steady work. 2nd, the reliability is good. In order to enhance the electric circuit work the reliability, not only the part passes through screens carefully, moreover pas
9、ses through 2 2400 hours to roast machine the experiment, its outer covering is exquisite, may install conveniently in the pocket, momentarily may take the use. 3rd, simplicity of operator, easy to operate. Only needs to insert to the cigar lighter on, does not need to get out, all OK. 4th, the use
10、security, felt relieved. Even if meets instead, also will not damage the instrument, will not damage on the vehicle anything. 5th, the speed may adjust. You may the speed regulation highest, may also adjust to a fixture, for instance 300 step. Is different based on the vehicle type, the speed differ
11、s from, may the speed knob change speed through the regulating instrument on. Monolithic integrated circuit AT89C2051 by its low price, the low power loss, the reliability high and easy to program and so on characteristics to be famous, X25045 is a MCS-51 series monolithic integrated circuit electri
12、c circuits auxiliary chip, mainly takes on the replacement, the voltage examination, the watch-dog and the EEPROM function, this chips use enhanced systems reliability greatly, reduced the periphery chip number, may realize the power failure which the course accumulates to save. LCM1010 is ten type
13、belt back light liquid crystal display module, uses three serial interfaces, it has the power loss to be low and programming convenient characteristic. This demonstration is divided two lines of demonstrations, the first line of 6 demonstration accumulation course, second line of 4 (1 decimal) uses
14、in demonstrating the sub-total course. In the chart K1 is the sub-total course reset key, R4 uses in adjusting liquid-crystal displays angle of view contrast gradient. Chip X25045 is Xicor Corporation promotes has programmable P monitors CMOS serial EEPROM, has 4096, according to 5128 organizes. It
15、has 4 bytes pages to write the way and 100,000 use cycles, the data may preserve for 100 years. In order to guarantee the accumulation course unit the units place or sub-total unit decimal place reliable refurbishing, when these unit close limit use cycle, may adopt the form feed the means to cause
16、these data to move to the new unit continues to count. The Hall sensor has many merits, their structure is reliable, the volume is small, the weight is light, the life is long, the easy installation, the power loss is small, the frequency high (may reach 1MHZ), bears the vibration, does not fear the
17、 dust, the greasy dirt, the 3 water vapor and the salt mist and so on pollution or the corrosion. The Hall linear units precision is high, the linearity is good； The Hall switch component non-contact, does not have the attrition, the output wave shape clearly, not to have the vibration, not to have
18、the rebound, the position repeat accuracy high (to be possible to reach m level). Has used each kind of compensation and the protective measures Hall components operating temperature scope width may reach - 55 150 . this design realizes the course by monolithic integrated circuit AT89C2051 to accumu
19、late, the sub-total, the reset and the memory, and actuates the cross coil meter by the LM1819 integrated circuit, thus has realized the vehicle speed instruction. Again using Hall sensor transmission signal. Realizes this design proposal cost to be inexpensive, the indicator stability is good, the
20、speed of response is quick, the anti-knocking property is strong, the reliability and the performance-to-price ratio are very high. After the actual use proof, this odometer definitely may substitute for the tradition the speedometer which actuates by the flexible axle. Certainly, this is only one k
21、ind realizes the plan, may also actuate the cross coil meter by the monolithic integrated circuit through the software, namely controls the meter separately by the monolithic integrated circuit the sine coil and the cosine coil omits the LM1819 integrated circuit. Regarding this, here no longer give
22、s unnecessary detail. The monolithic integrated circuit curriculum was already the practical very strong specialized technology curriculum, the beginner only then through the massive programming, the experiment, the debugging, the design manufacture and so on a series of practice links training, cou
23、ld understand truly the monolithic integrated circuit software and the hardware design and the debugging skill, could the nimble utilization monolithic integrated circuits each command system and each kind of development debugging aids, design highly effective, reliable, the low power loss, the volu
24、me smaller monolithic integrated circuit application system, manifested monolithic integrated circuits embedded application characteristic fully. Must carry on monolithic integrated circuits development, the experiment and the curriculum project and so on, must have a set of software and hardware development kit, like this may save many precious time and the energy, raises the
