Make Digital Stopwatch

Introduction

To make an advanced stopwatch circuit that can check from 0 to 99 seconds, which can likewise be utilized for various applications like photograph counter, individual counter, check down clock, morning timer and so forth. with little adjustments.

Segments USED:

1. ICs:

I. CD4060BM – 14 phase swell convey twofold counter - 1

ii. CD4040BM – 12 phase swell convey twofold counter - 1

iii. NE555 – Timer - 1

iv. MC14518B - BCD counter - 1

v. MC14511B - BCD to seven portion show drivers - 2

2. Different parts:

I. 1 kilo ohm resistors – 16, 10 kilo ohm resistors - 2, 1 super ohm resistor - 1, 330 ohm resistor - 1,220 ohm resistor - 1

ii. 100 kilo ohm potentiometer-1

iii. On/off switches-2

iv. 4.2 megahertz gem 1

v. 1N4007 diodes–2

vi. Regular anode 7 fragment shows - 2

vii. +5V DC power gracefully

viii. Bread board - 1

CIRCUIT DESCRIPTION:

The circuit can be fundamentally isolated into three sections. One is generator which creates the beat of the ideal recurrence. Different parts are the counter that does the real tallying of the seconds and the presentation unit.

Heartbeat GENERATOR:

The generator of the circuit involves the incorporated circuits CD4040CM and CD4060CM. We utilize a gem which wavers at a recurrence of 4,194,304 Hz. Clearly this recurrence is totally pointless, as it is too enormous to be utilized all things considered to our circuit. What we ought to is partition this recurrence, in a path that in its last structure, the beat will have a recurrence of 1Hz, which is the alluring recurrence. At first we utilize the coordinated CD4060, which separates the imported recurrence in its information, by powers of 2. As should be obvious on the coordinated circuit the yields are set apart as Q4, Q5,… ,Qn. By bringing in a heartbeat in the CLK input of the 4060, with a recurrence f Hz, we remove from yield Qn, a sign which has a recurrence equivalent to f/2n. In this way, by sending out the sign out of Q14, realizing that the imported sign has a recurrence of 4,194,304 Hz, we take a sign, which has a recurrence of 256Hz. By bringing in this sign, to 4040 and by trading the sign through Q8 we have at last taken a modified sign, at the recurrence of 1Hz. The way that the sign is transformed, doesn't influence the correct capacity of our circuit.

This reversal admirable motivation the circuit to be set off with a consistent 0. By putting a LED on a similar yield, we have a visual of the checking, as in every certain heartbeat the diode energizes emphatically, and a current goes through it.

COUNTER:

This incorporated circuit includes a legitimate 1 at each heartbeat, on its yield. The MC14518 is basically isolated into two fragments. One tallies the units of the seconds, while the other the decades. The generators beat is imported to the part which tallies the units. This is intelligent, as we need in each second the quantity of the showcase to be raised by 1.

Then again, we need the principal show to raise by 1, like clockwork. This is the reason, we ground the CLK input, furthermore, we utilize the sign of Q3 to the CKE input. By utilizing this implies, we ensure that the principal show will be set off, just when we have a diminishing sign on Q3; that is, just when the sign drops from legitimate 1 to intelligent 0.The first presentation increases like clockwork, which implies that following 9 on the subsequent showcase (1001 on the yield of the BCD counter) the first show must be set to zero, while the primary must be set to +1. That will be that from 1001 to 0000, and we have a plummeting beat, as the last digit slides from coherent 1 to consistent 0 and triggers the BCD counter of the decades. At the point when the decades show becomes 9 then the circuit goes to the following state, which is zero, and the checking starts again.

Show UNIT:

The incorporated circuits MC14511 are BCD to 7 portion drivers. As its name unmistakably express, their sole reason for existing is to interpret the BCD data of MC14518, to a code justifiable by the 7 fragment shows. The sources of info LE, BL' and LT' are utilized to test the LEDs of the showcase and heartbeat tweak the splendor of the presentation. For this situation we these contributions to intelligent 0, as we needn't bother with them. The LE input (Latch Enable) is utilized to keep the quantity of the showcases while the beat despite everything runs. It is a HOLD work like the one of the advanced stopwatch. Also, at some random second we can restart the checking, by squeezing the reset switch. By this implies we set the RST contribution of the MC14518 to legitimate 1, which resets the tallying to 0000

Adjustments:

The circuit which we depicted above for the 1Hz heartbeat age utilizing precious stone of full recurrence 4.2 MHz is exact than some other heartbeat generators. Yet, the precious stone was not gotten. So we structured distinctive 1 Hz beat creating circuits. At long last the circuit utilizing NE555 could fulfill the prerequisites of the venture. The circuit has been tuned precisely tuned to 1Hz by changing the potentiometer's opposition. The examination has been made by squinting a drove with 1Hz clock heartbeat on advanced coach unit and flickering another drove with the heartbeat delivered from the circuit planned utilizing NE555. The 1Hz heartbeat created has been given as clock contribution to the second BCD counter of MC14511.

Proposed Circuit Schematic:

Subtleties of ICs utilized:

1. MC14518B: The MC14518B double BCD counter and the MC14520B double parallel counter are built with MOS P–channel and N–channel improvement mode gadgets in a solitary solid structure. Each comprises of two indistinguishable, autonomous, inside simultaneous 4–phase counters. The counter stages are type D flip–flops, with tradable Clock and Enable lines for augmenting on either the positive– going or negative–going progress as required while falling numerous stages. Each counter can be cleared by applying an elevated level on the Reset line. Likewise, the MC14518B will tally out of all vague states inside two clock periods. These complimentary MOS up counters discover essential use in multi–stage simultaneous or swell tallying applications requiring low force scattering or potentially high clamor invulnerability.

2. MC14511B: The MC14511B BCD–to–seven portion hook/decoder/driver is built with correlative MOS (CMOS) upgrade mode gadgets and NPN bipolar yield drivers in a solitary solid structure. The circuit gives the elements of a 4–piece stockpiling lock, a 8421 BCD–to–seven portion decoder, and a yield drive ability. Light test (LT), blanking (BI), and hook empower (LE) inputs are used to test the showcase, to kill or heartbeat balance the brilliance of the presentation, and to store a BCD code, separately. It very well may be utilized with seven–fragment light–producing diodes (LED), glowing, fluorescent, gas release, or fluid gem readouts either straightforwardly or then again in a roundabout way. Applications incorporate instrument (e.g., counter, DVM, and so.) in plain view driver, PC/number cruncher show driver, cockpit show driver, and different clock, watch, and clock employments.

3. CD4040BM and CD4060BM: These are 12 organized and 14 arranged wave convey paired counters individually. TheCounters are progressed one rely on the negative change of each clock pulse.The counters are set to zero state by a sensible ‗1' at the reset input free ofclock. Pin outlines: CD4040BM: CD4060BM:

4. NE555:The NE555 IC has three working modes: 1. Mono stable mode: in this mode, the 555 capacities as a "one-shot". Applications incorporate clocks, missing heartbeat location, skip free switches, contact switches, recurrence divider, capacitance estimation, beat width tweak(PWM) and so forth 2. Utilizations incorporate LED and light flashers, beat age, rationale timekeepers, tone age, security cautions, beat position tweak, and so on 3. Bi-stable mode or Schmitt trigger: the 555 can work as a flip-flop, if the DIS pin isn't associated and no capacitor is utilized. Utilizations incorporate skip free hooked switches, and so forth. Pin graph:

5. Utilizations of the circuitThe primary reason for the circuit is to utilize it as a stop watch that can be utilized inorganizing sports, tests and so on. With little adjustments, the circuit can be usedfor many including purposes.The flip-flops in the counter MC14518 are edge set off. So in the event that we give a singlepulse, the tally increases by 1. So in the event that we supplant 1Hz heartbeat generator circuit witha photograph sensor, the check increases by 1 just when a heartbeat is gotten. So thecircuit can be utilized as photograph counter. It tends to be kept inside a table's work area. Wheneverthe work area is opened, the check increases by 1.So an individual can discover howmany times the table has been opened in his nonappearance and reset the counter. The circuit can likewise be utilized as individual counter with the assistance of two IR sensors.One is to deal with the tally of the people. Other is to discover, regardless of whether the individual isentering the room or leaving. At the point when an individual goes into or leaves the room, he will cutthe light beam produce by IR leds. So the check increases by 1, when a personenters the room and decrements by 1, when an individual leaves the room. It can bereset, at whatever point it is required.If we supplant up counter with down counter, it very well may be utilized as commencement clock oralarm clock by joining a signal for sounding. On the off chance that the 1Hz heartbeat generator circuit is supplanted with a Pressure sensor, the circuit canbe utilized for tallying the quantity of people strolled through a way. This can madeuseful for handy purposes by expanding the no. of counters and seven segmentdisplays, accordingly expanding the most extreme conceivable tally.

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