Helios

Helios

Helios is a circular LED chaser PCB built using an NE555 timer and CD4017 decade counter. Ten LEDs are arranged around the outside of the board and light up one after another, creating a rotating light effect.

The PCB was designed in KiCad and uses a circular layout with custom Helios-themed silkscreen artwork.

How it works

The NE555 timer is configured in astable mode, meaning it continuously generates electrical pulses without requiring an external trigger.

A 50k potentiometer controls the timing of these pulses, allowing the speed of the LED sequence to be adjusted.

The output of the NE555 is connected to the clock input of a CD4017 decade counter. Every time the CD4017 receives a pulse, it advances its active output by one:

• the first pulse activates Q0
• the next pulse activates Q1
• this continues through Q2, Q3, etc. until Q9
• after Q9, the counter returns to Q0 and the sequence repeats

Each of the ten outputs is connected to one of the ten LEDs positioned around the edge of the PCB. This makes the illuminated LED appear to travel around the circular board.

A 470 ohm resistor limits the current flowing through the LEDs, while the circuit is powered through a 5V connection.

Turning the potentiometer changes the frequency of the pulses generated by the NE555, so the LEDs can chase around the board faster or slower.

Hardware

This repository contains all the hardware files you would need to replicate this project. Everything was done in KiCad.

The pcb folder contains the KiCad source files (.kicad_sch, .kicad_pro, .kicad_pcb) and the gerbers.zip which was used to manufacture the PCB.

Images

This is what the schematic looks like:

This is what the PCB looks like:

This is what the PCB looks like in 3D:

BOM

Also in the BOM.csv file.