Introduction: Simple Counterfeit Money Detector - UV Black Light Lamp < 2$

About: DIY my way through life. For me, Instructales is a way of living. It's my making log. My life is counted with the instructables I make. Visit my website and If you need more Arduino Mentoring for your class yo…

In this post I 'll show you how to make an Ultraviolet Lamp ( Black Light) in less than 10 minutes and for less than $2.

This setup can be efficiently used as a low cost counterfeit money detector.

Lots of banknote has a built-in small pieces of material that can induce Fluorescence.

The good news is that you can use this lamp not only as a counterfeit money detector , but also as a scientific and fun toy that you can explore different materials having the Fluorescence.

Please take care not to look directly at the UV light for long times as it may be harmful for your eyes.

Here is my Channel on Youtube:


Step 1: Material Used

All you need is :

LED Pocket Lamp. Amazon or eBay

UltraViolet LED. Amazon or eBay

Or you can get it ready made from Amazon or eBay.

Step 2: Gentle Disassemble

Start disassembling the LED lamp to get the white LED out of its place.

The LED Lamp you have may differ from the one shown here.

Step 3: Prepare the UV LED

First, you must to know the polarity of the LEDs.

In the new LED, the longer pole is the +ve .

You can also find the orientation of the LED by comparing the shape of the UV LED with the white LED.

The LED has a wider part of metal inside the plastic part near to one pole.

You just need to insert the UV LED in the same orientation as the white LED.

In my LED lamp, the batteries are set in a way that -ve poles are upwards and +ve poles are downwards.

Then , Adjust the LED legs.

In my lamp, the -ve pole of the LED is connected to the -ve pole of the battery and the -ve pole of the LED is bent to be placed adjacent to the battery.

The UV LED now is ready for insertion.

Step 4: Insert the UV LED

My LED Lamp had a white LED that is bigger than the normal UV LED. So , I had to put a piece of cartoon paper to support the UV LED inside the white LED holder.

I inserted the UV LED.

Then inserted the batteries.

Then the metal strip.

Then tested the lamp with the new LED by manually making the metal strip touch the +ve pole of the LED.

Reassemble the lamp with the new LED.

Step 5: Use You Black Light Lamp

Now, it is time to use your Black Light lamp.

Check all the money banknote you can check. Money has some invisible marks that cannot be seen in the normal light.

But under Ultra-Violet or Black light , they can be easily seen as shown.

You can also try your lamp with any material in your home.

By experiments, I found that white and orange objects reflect more UV light than any color.

You can also make some experiments with these balloons .

Please take care not to look directly at the UV light for long times as it may be harmful for your eyes.

Thank you for reading my instructable.

You can also find my book Learn By Making on Amazon website.

If you like this instructable you can support us by many ways:

1. Leave comments stating your point of view about this article.

2. Buy our book on Amazon Learn By Making.

Thank you for visiting our instructable.

Here are some of my latest books on Amazon.

Learn By Making

Backyard Wind Turbines

Supercharged Contest

Participated in the
Supercharged Contest