USB Fading Star




This circuit uses a 555 timer IC and BC547 transistor which are cheap and commonly available and works on USB 

Step 1: Parts List

1   x NE555
1   x BC547
1   x 33K resistor
1   x 500 r variable resistor
1   x 9V battery
24 x LED red ( or other colors) 

Step 2: Circuit Diagram

Complete the circuit according to the circuit diagram, it is simple and has only minimum components, I used 5mm LEDs for the circuit,
 an IC socket for IC and for the transistor to prevent the components from burning due to the heat while soldering 

Step 3: Step 1

I had made a star using 5mm red led (you can make what ever shapes). for making it, i used a 3mm metal sheet cut into a square of 7cm and  drilled holes  as the shape of a star. when the USB  is plugged in the star light up and the slowly fades the light intensity can be varied by the variable resistor (500 ohm) 

Step 4: Step 2

Check for any errors in connection by connecting the Led circuit to a 3v battery source

Step 5: Step 3

For connecting the USB cable to the circuit, find a USB cable, open its pin portion you will find four wires, desolder the wires then remove any two wires of your choice and then connect the rest two wires, one in the upper end and other in the lower end, in the picture shown the red is the positive wire and brown is the negative wire. cut the other end of the cable connect the same two wires to the positive and negative of the circuit. then just plug it in to the USB slot

Step 6: Conclusion

Hope you liked the circuit. please rate it and if you have doubts or any comments the please comment  and rate it........  this is the fade in or fade out effect



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    12 Discussions


    6 years ago on Introduction

    so you have soldered the led's negative with negative and positive with the positive ? and it's okay?

    thank you!


    7 years ago on Introduction

    Thanks so much, this is exactly what i was looking for then, what is the rough time it takes to go through a cycle? from full on to faded and back to full on?

    2 replies

    Reply 7 years ago on Introduction

    Alright, thanks so much, 5 stars :), you have been very helpful, keep up the good work.


    7 years ago on Introduction

    just wondering but i wanted to use this same wiring technique for another lighting project, is the fading automatic on the star? i am looking to make 2 led's light up and fade in a speed similar to a slow heart and the is the fade instant like a lightbulb or can you see it fade, if anyone can answer my questions that would be greatly apreciated, also if there is a video on youtube of the project or similar that would help too.

    I am looking to make a steampunk light that pulses like a heart beating for my girlfriend for christmas.


    7 years ago on Introduction

    Hello! Good project!... But ... usb is limited to 5 V 100 mA, and your project cannot lit 24 red leds without reaching more than 100 mA..

    how do you do?


    3 replies

    7 years ago on Introduction

    Can someone please link me to where i can buy a variable resistor that could be used in this circuit?? And where does the circuit board go? kinda confused, this is my first build from this site (: