LED Chaser Circuit using 555 Timer IC & CD4017

Overview

In this article, we will make an LED Chaser Circuit using 555 Timer IC & CD4017. An LED chaser is an electronic circuit that creates a visually appealing effect by sequentially illuminating multiple LEDs, one after the other, in a repeating pattern. This creates the illusion of a “chase” or a “running light” effect, as the illuminated LED appears to move across the array. LED chasers are popular in various applications, such as decoration, signage, display panels, and festive lighting.

This can be achieved using a 555 timer IC and a CD4017 decade counter IC. The 555 timer generates a clock pulse, and the CD4017 divides the input frequency and sequentially drives the LEDs. Here’s a simple way to build an LED chaser circuit using the 555 timer IC and the CD4017 decade counter IC.

Components Required

1. 555 Timer IC
2. CD4017 Decade Counter IC
3. LEDs – 10
4. 10kΩ resistor – 1
5. 220Ω resistor – 10
6. 10kΩ Potentiometer – 1
7. 10µF capacitor
8. 10nF capacitor
9. Breadboard or PCB
10. Jumper wires
11. 9V battery or power supply

Circuit & PCB Design

The following is the LED Chaser Circuit designed using 555 Timer IC & CD4017 Decade Counter IC.

Here is the PCB for this project designed using EasyEDA Software.

The Gerber File for the PCB is useful in manufacturing the PCB.

This is the 3D view of the PCB which looks awesome.

For testing purposes I used Vero Board and assembled all the components there.

Power the circuit using a 12V Battery.

Working of LED Chaser Circuit based on 555 Timer & CD4017

Once the circuit is complete, apply power to see the LEDs chasing one another in sequence. The speed of the chasing effect can be adjusted by changing the values of the resistors and capacitor in the 555 Timer IC circuit. For example, you can try different resistor and capacitor values to find the chasing speed that suits your preference.

In this LED Chaser Circuit project, we have set up a 555 timer as an Astable multivibrator, where both signal stages are unstable, and it functions as a frequency generator. The output signal of the Astable multivibrator is used to trigger the CD4017 counter IC to change its state and execute the desired action.

The 555 timer IC is connected in Astable mode to produce a trigger pulse with a specific time period. A variable resistor is included to adjust the output frequency of the 555 timer. A CD4017 counter IC is also incorporated in the circuit for controlling the LEDs. Ten LEDs are connected to the Q0-Q9 pin (pin 3) via a 220-ohm resistor. The MR pin (pin 15) and the enable or clock inhibit pin (pin 13) are directly connected to the ground, while the clock pin of the counter is directly connected to the output pin of the 555 timer.