Very Small USB Light

Introduction: Very Small USB Light

About: I am a college student in Electronics Engineering Technologies. I have been fascinated with LEDS for the past 15 years, and have been building electronics project since the age of 8. I am fluent in 3D printing…

Hello fellow makers!

Today, you will learn how to build a very small USB flashlight that can be used with USB power banks or plugged into a wall charger to create a small night light.

This is a very quick build, and only takes approximately 10 minutes.

Lets get started!

Step 1: Tools and Materials

For this project, you will need:

1 Circuit board that has connection contacts along the edge (See photo) you may also use an old computer PCI card or the such.

1 White LED (3V/20mA)

1 100Ω resistor


Soldering iron and solder

Wire cutters

A very solid box cutter (to cut the circuit board)

Metal ruler

Step 2: Cutting the Circuit Board to Shape

Align the ruler on the egde of the contact tabs, as shown in the first picture. Cut several cuts, being careful so the ruler remains in place. You will need to go over this cut 10 or 15 times to make a good score line.

Snap the circuit board along the score line.

Turn the circuit board 90° and align the ruler in a way so that there will be 4 contacts between the ruler and the edge of the board. Refer to the picture for a better understanding.

Cut again, and previously described, cut 10 or 15 times, and snap on the score line.

You will remain with a small rectangle of the circuit with 4 contacts, and shown in the 3rd picture.

Step 3: Preparing the Board

You will now add solder along the whole length of the 2 outer contacts. This will "bulk" up the board to make it a bit thicker. It will also assure a good contact once it's put in the USB charger.

The third picture is just to show which contacts will be positive (+) and negative (-).

Step 4: Soldering Components

Cut the leads short on the resistor, and tin both ends with solder.

Solder one end to the (+) of the USB as shown in the picture.

Cut the (+) lead of the LED short, and tin this lead with solder. See the second picture to know where to cut.

Solder the LED to the end of the resistor.

The last lead is bent into place, using your fingers or pliers. Optionally, add a small piece of shrink-tubing over this lead.

Once bent into shape, cut the lead to the correct length and solder to the (-) contact.

Congratulations, you are now done! :-D

Step 5: Enjoy Your Light!

In the first 2 pictures, it is plugged into a USB power bank

The rest of the pictures, it is plugged into a phone charger by my washing machine. You can see this produces a good amount of light to be used as a night light.

Thanks for reading, and let me know if you liked this project in the comments!

Cheers from Canada

Make it Glow Contest 2018

Participated in the
Make it Glow Contest 2018

Be the First to Share


    • Paint Challenge

      Paint Challenge
    • 3D Printed Student Design Challenge

      3D Printed Student Design Challenge
    • Unusual Uses Contest

      Unusual Uses Contest



    2 years ago

    Hi,you can soldering in this mode to save dimension.Resistor can mount in parallel with Led.
    If you use a USB male connector(from mouse or others useless)you can resolve problems about usure.


    Reply 2 years ago

    Hi, unfortunately, as ElectroFrank said, you can't connect in this manner. The resistor limits the current in the branch connected to the LED. If connected in the manner you've shown, you will have 2 branches. The first branch will be the resistor, and the second would be the LED. The current would not be limited within the LED, thus, destroying it almost instantly.

    Thanks for commenting!


    Reply 2 years ago

    No. The resistor MUST BE IN SERIES with the LED. If connected as your diagram, it will immediately destroy the LED.


    2 years ago

    I'd be worried about the components ripping apart when I was removing it from the usb port, as such I'd be tempted to leave a bit more of the board to protect the components from damage and give a bit more to grip onto.

    Out of interest how do the contact strips of solder hold up in terms of wear and tear? I'd be worried about having scraping of solder causing problems (shorts?) in the port


    Reply 2 years ago

    You definitely bring up some good points there. As for durability, I would definitely encase it in hot glue, which I should have mentioned. As for the solder, if you're using a good grade of solder and flow it well, it should come out very evenly and shouldn't be an issue for wear. The solder is a pretty soft alloy, but as you seem to have noticed, this device isn't something that you'd want to handle and plug/unplug 100's or 1000's of times.

    I made a slightly bigger model, which uses an actual USB plug and is completely encased in shrink-tubing. I will have to make another and post an Instructable, but here is a teaser (the attached picture) ;-)

    That being said, I will most likely just use this one as a night light. This is sort of a 10 minute project.

    Thanks for your comment!