CN2141568Y

CN2141568Y - Liquid crystal display tachometer

Info

Publication number: CN2141568Y
Application number: CN 92236731
Authority: CN
Inventors: 贾欣
Original assignee: Individual
Current assignee: Individual
Priority date: 1992-10-24
Filing date: 1992-10-24
Publication date: 1993-09-01
Anticipated expiration: 2002-10-24

Abstract

The utility model discloses a liquid crystal display tachometer which relates to a tachometer used for displaying the rotational speed of motorcycle engines or automobile engines. The liquid crystal display tachometer comprises a casing and a liquid crystal display circuit arranged in the casing, wherein, the liquid crystal display circuit comprises a shaping circuit, a BCD counter, a liquid crystal display driver, a liquid crystal display screen, a time-base gate circuit, a latch pulse circuit, a zero clearing pulse circuit, and a power supply circuit. The rotational speed pulse sampled from the ignition system of a motorcycle engine or an automobile engine displays on the liquid crystal display screen after-shaped, latched, counted, and decoded. The liquid crystal display tachometer has the advantages of less power consumption, and clear and stable display, and the liquid crystal display tachometer does not influence the service life of vehicles components.

Description

Liquid crystal display tachometer

The utility model relates to a kind of tachometer gage that is used to show motorcycle or rotating speed of automobile engine.

Motorcycle and rotating speed of automobile engine are one of important operational factors of engine, and be clear and show that stably the engine transient speed helps in time understanding the operation conditions of engine.In the prior art, the tachometer gage of demonstration motorcycle or rotating speed of automobile engine mainly contains mechanical type, several classes such as magneto-electric and photo-electric.Mechanical type and magneto-electric rotating speed are stable inadequately to the demonstration of rotating speed, display error is bigger, and mechanical friction is to also there being certain influence in serviceable life of vehicle tyre or flexible axle.Photoelectric tachometer, owing to adopt the diode displaying rotating speed more, so its power consumption is bigger, it is also clear inadequately to show under high light.

The purpose of this utility model is that a kind of power consumption of design smaller and also can show the tachometer gage of engine speed under the high light environment steady and audiblely.

To achieve these goals, the utility model adopt the liquid crystal display circuit be installed in the housing to take a sample in the tacho-pulse of motorcycle or car engine ignition system in addition after the shaping input BCD counter latched and counted, and by LCD driver the timesharing output of BCD counter decipher and to be driven on LCDs directly demonstration engine speed.Be described in further detail below in conjunction with the technical characterictic of specific embodiment the utility model liquid crystal display tachometer gage.

Accompanying drawing 1 is the liquid crystal display circuit figure of the utility model liquid crystal display tachometer gage.

With reference to the accompanying drawings 1, the utility model liquid crystal display tachometer gage mainly is made up of housing and the liquid crystal display circuit that is installed in the housing, liquid crystal display circuit mainly comprise shaping circuit, BCD counter, LCD driver, the time basic gate circuit, latch pulse circuit, quenching pulse circuit and power circuit.Be shaped as count pulse behind the tacho-pulse input shaper circuit of motorcycle engine magneto generator or distributor of automobile engine sampling and import the BCD counter and latch and count, the timesharing output of BCD counter is driven by LCD driver decoding and is shown on LCDs.Base gate when time base gate circuit provides counting for the BCD counter, latch pulse circuit and quenching pulse circuit are respectively the BCD counter latch pulse and quenching pulse are provided, power circuit be respectively shaping circuit, BCD counter, the time base gate circuit, latch pulse circuit, quenching pulse circuit, LCD driver and LCDs D.C. regulated power supply or square wave power are provided.

Shaping circuit can adopt the schmidt door of being made up of 40106 chips (IC1-1), takes a sample and imports through diode or electric capacity in the tacho-pulse of motorcycle engine magneto generator or distributor of automobile engine, and its shaping output is as the count pulse of BCD counter.BCD counter IC2(MC14553B chip) be three BCD counters, the BCD counter that its inside has three negative edges to trigger, these three BCD counters with the cascade of synchronous working mode together, each BCD counter output all has four latchs, the count value of any time can be latched and cooperates the timesharing output (Q0-Q3) of finishing BCD rolling counters forward value with traffic pilot.Numeral selection output (

DS1-DS3) provide and the synchronous control signal of timesharing output, constitute dynamic display types, low level is effective.The BCD-that LCD driver is made up of three MC14543 chips (IC3, IC4, IC5) latchs seven sections decoding LCD driver, its input is from the Q0-Q3 of IC2, and the BI of IC3-IC5 links with the DS1-DS2 of IC2 respectively.When DS1 was low level, IC3 showed the synchronous and time-sharing output (Q0-Q3) of IC2, other two blankings.IC4 and IC5 circulate according to this and analogize, because scan round cycle persisting the time much smaller than human eye vision, so can obtain the numeral of quite stable on LCDs (LCD) shows, time base gate circuit is made up of multivibrator IC1-2 and buffering amplifier IC1-3 and basic gate when providing counting for the BCD counter, the width of base gate can make the count pulse number in gate time equal 1/10 of engine speed during adjustment, like this, add the actual speed that " 0 " is engine behind the number that LCDs LCD shows.The latch pulse circuit can by R4, C3 and IC1-4 forms and provide latch pulse for the IC2BCD counter, the quenching pulse circuit can by R5, C4 and IC1-5 and IC1-6 forms and provide quenching pulse for the IC2BCD counter, power circuit comprises two parts, R1, C1, D2 and E form D.C. regulated power supply and for IC1～IC6 provides the direct current stabilized voltage supply, R6～R8, C6 and IC6(4070 chip) form square wave power and provide square wave power for IC3～IC5 and LCDs LCD.

The utility model power consumption is little, clear display stable, and vehicle part is had no effect serviceable life, so be particularly suitable for showing motorcycle or rotating speed of automobile engine.Add after the suitable sensor that the utility model also can be used as the tachometer gage that shows bicycle or other rotating mechanism rotating speed.

Claims

1, a kind of liquid crystal display tachometer gage that is used to show motorcycle or rotating speed of automobile engine is characterized in that it is made up of housing and the liquid crystal display circuit that is installed in the housing; Described liquid crystal display circuit comprises shaping circuit, the BCD counter, LCD driver, LCDs, time base gate circuit, the latch pulse circuit, quenching pulse circuit and power circuit, input BCD counter latchs and counts after being shaped as count pulse from the tacho-pulse input shaper circuit of motorcycle or car engine ignition system sampling, the timesharing output of BCD counter is driven by LCD driver decoding and is shown on LCDs, base gate when time base gate circuit provides counting for the BCD counter, latch pulse circuit and quenching pulse circuit are respectively the BCD counter latch pulse and quenching pulse are provided, and power circuit is respectively shaping circuit, the BCD counter, time base gate circuit, the latch pulse circuit, the quenching pulse circuit, LCD driver and LCDs provide D.C. regulated power supply or square wave power.