LED CHASER With IC555 and IC4017

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Introduction: LED CHASER With IC555 and IC4017

Here we are going to make LED chaser. The chasing illusion of frequently turning ON and turning OFF of adjacent LED in a string of LED is called LED chaser. LED chaser circuit mainly consists of two circuits. one is of IC555 and another one is of IC4017. The IC555 circuit is mainly used for providing free running frequency output. and IC4017 is binary decade counter. which can count up to 10 states.

ic555 astable multivibrator

Step 1: Materials Required

1. IC555

2. IC4017

3. LED

5. Connectors

6. Capacitors ( 47uf,.01nf)

7. Power source 5v

8. Wires

9. Resistors ( 100 ohm)

10. Resistor pot ( 10k)

Step 2: Circuit Diagram and Explanation

astable multivibrator

IC 4017 is a 16 pin out ic. which can count up to 10 states. IC 4017 mainly consists of two internal blocks

1. Counter

It has 3 inputs and 4 output.

inputs are

1.clock input ------ connected to 14th pin of ic4017

2.reset---------------connected to 15th pin of ic4017

3. clock enable-----connected to 13th pin of ic4017

The output will be in the format of a 4bit binary code

eg; 0000 or 1001 or 0111

2. Decoder

The decoder converts the binary number to decimal number. Here, each output pin of ic4017 is referred to a decimal number. according to the input, the decoder decides which pin has to go HIGH.

conversion of binary to decimal

0000 -----> 0
0001------> 1

0010------> 2

0011------> 3

0100------> 4

0101------> 5

0110------> 6

0111------> 7

1000-----> 8

1001------> 9

Pins of ic4017

1.) Pin 16

it is the positive power supply

2) pin 8

it is the ground

3) Pin 13

it is the Clock enabled pins to controls the clock.When it is “0” logic, the clock is enabled and the counter advances one count for each clock pulse. When “1” logic, the clock input is stopped, and the counter does nothing even when clock pulse arrives.

4) Pin 14

It is the clock triggers one count.

5) Pin 15

It is the reset pin. Normally, it is “0”. When made “1”, the counter is reset to “0”.

6) Pins 1-7 and 9-11

They are the decoded output pins. The active count pin goes high and all others remain low

7) Pin 12

it is the Carry output, for the clock input of an additional counter or an external circuit that the count is complete.

Step 3: LED Chaser With IC4017 and IC555

Circuit the diagram as shown in the figure.

Step 4: Connect Ic555 to Ic4017

since I already have developed astable multivibrator. The output of the astable multivibrator is connected to the clock input of the ic4017. The speed of the running light can be varied by changing the resistance of the ic555. make sure both the circuit have common ground.

Step 5: LED Chaser Working in Different Frequencies

These are the LED chaser with different frequency input. the frequency can be varied by changing the resistance of the ic555.

Step 6: Similiar Project

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12 Discussions

you used ic 555 and ic 4017 to make it which is quite
big to feed inside the case. but in china made only one 8pin ic is used. can any
one tell me what ic is this (5072B is written on the top of this chip)

I just "LOVE" the 555. I've done dozens of app's with it since early '80,s, (Yes, allmost 40 years ago). Your ible is wery nice for a beginner, it gives a "hum" of the functionality of the 555 and the digital side of functions with the 4017. However, because only one output of the 4017 is active at a time (HIGH), wouldn't it be smarter to have only 1 resistor common to all, (the cathode side)?

consider a situation, in which the frequency is very higher.

Taking a small time period, there will more than one or multiple LED is ON at the same time.

won't it be affecting that? :/

Hi. Your on "right" track with your ible. Howewer, take a TV-reciver: it displays , (in Finland), 2x25 frames, (overlapping each other), ower your screen, thus giving you a illusion of a movement. Same thing at Movie theatre, with 25 frames/second. So if you speed up yuor LED-display with 8 leds to a speed of ~50fr./sec./8 LEDS to lit in a sequence/second, with only 1 lit at a time. The speed for ewery individual LED would be 1sec./50/8 = ~10msec./LED.
That would be a speed of 100Hrz. And that would make it to seem if they "ALL" were lit at the same time. Make that freq. to be in 10's of KHz ~ up to MHz and you could lit up thousends of LED-s in a seq. and still it looks like to be lit all at the same time. So, the speed is not a issue here

At very higher frequency. almost all the LED will be switched ON at the same time.(since frequency is higher the switching time will be very less and all the LED switched ON at the same....)

when all the LEDs are active at same time.the voltage drop will be very less and LED may burn out.

thats why i think we have to use seperate resistor for each LED

Oh Boy! Take a look at the tech. spec. of a 4017, and You will find out that it’s capable of MHz with its output, (that's in a class of ”million’s”/second). BUT ”STILL” with ”ONLY 1” output active at a time, so that said.

Thanks man... I will give a try.... ;)

Actually:

1.) The frequency of the shift can go up to MHz, (MegaHerzts = millions of changes/second), still, "JUST ONE" bit active at a time, so that.

2.) The human "brain" can't make a difference in of an eye seen thing with an alternating speed of more than 25 "frames"/second, (e.g. "The movies" play appr. 25-50 "still-pictures"/second). That's why there "seems" to be more than one LED's lit at the same time. Take a look at the tech. spec. of 4017