Can a Metal Detector Detect Money? Simple Explanation

There is no point hiding it anymore as modern science and technology discovered metal detectors that can detect cash and tell the exact amount you have on you. 

Metal detectors of this kind, which can easily detect cash, first appeared in the United States of America. Government agencies solely use it for security reasons to hunt down the illegal propagation of US banknotes.

Can a Metal Detector Detect Money?

metal detector
The Invention and Use of Metal Detectors That can Detect Money

This thing became extremely popular among netizens after its appearance on the famous television series, The X-files. Not only for US banknotes, but any kind of money printed using magnetic inks is also detectable by these metal detectors. They can detect it and give you the exact number of them too. 

The actual thing which the metal detector reads is the metallic inks in the banknotes. And by that exact information, it can also tell the number of them present. Various vending machines already use these magnetic inks to check the genuineness of currency notes. 

Who were the Investors?

Now, don’t you want to know the great minds responsible for the invention of such the great machine? The inventors of this kind of metal detector (able to detect and count cash) were physicists Antao Chen and Christopher Fuller. Both of them are linked with Washington 

University located in Seattle. The idea behind making this was that they knew large bundles of currency notes should contain sufficient magnetic lines that could be detected from a distance by using a simple but technologically advanced metal detector.

This was a great step towards the safety and security of the country, as it stops and catches smugglers who try to smuggle huge amounts of cash over the country’s border.  

They realized that a normal handheld metal detector could detect the US dollar bill if held from 3 centimeters away. The distance was problematic in this case.

Challenges Faced

To increase the strength of a metal detector, there must be technological advancements to get cash from a distance far more than 3 cm. That was the challenge in front of Christopher and Antao. 

For quickly added information here, if the bank notes are kept covered with any forms of cloth, cardboard, or plastic, it does not block any signals and is still detectable by a metal detector.

Think of the explosives carriers; they hide them under their clothes but still get easily detected by the metal detectors. 

Talking about the modern metal detectors, their signal increases significantly when more than more currency notes pile up. Hence, the more the number of notes, the easier it is for the detectors to detect it and count the exact number simultaneously.

Although, getting this same signal quality for fewer notes is still tough. The performance of the sensors deteriorates when the number of currencies becomes fewer. It is the same magnetic ink present in all the currency notes. 

It is not a great deal to think about the low signal of the metal detectors for fewer notes. Because the purpose of this machine was based on security, especially to stop the smuggling of vast amounts of US currency notes across its borders.

So, it does not matter if the fewer notes, resulting in a poor signal of the metal detector. You know that carrying 150 dollars can’t get anyone booked under the violent charges of smuggling! Hence, the prior purpose for which these advanced metal detectors are used to detect huge amounts of money is fulfilled.

Using these metal detectors is precisely the same as an ordinary metal detector. It is pretty simple: wave the black detecting tool at the pockets, the body of the concerned person, and his/her belongings to detect anything that has any metal in it. 

It receives the signals and detects the presence of banknotes with the bit of magnetic ink by which notes are printed. A question may arise that there are various currencies where magnetic ink is still not in use to print banknotes.

Can metal detectors be able to detect those kinds of currencies too? The answer to this is ‘no.’ If an item has no metal tinge in it, it becomes impossible for a metal detector to detect, as the name suggests. 

When the first metal detectors (worthy of detecting cash too) were invented and were in their early stages, they counted the number of bills but not the exact amount of cash. After further developments, it can count the exact amount of money.

The failure to count the exact amount of money is that the amount of magnetic ink in a 10 dollars bill is just the same as it has in a 100 dollars bill. The same goes for a 100 dollars bill and a 1000 dollars bill. But, just as many other machines, metal detectors are now in a different level of advancements. 

Can Metal Detectors Sometimes Fail to Detect Money? 

No matter what, there is nothing wrong if the incredible gets even better. The large-sized metal detectors, significantly those widely used in airports and ship ports, should also elevate their range of sensing cold cash.

Sometimes, it is often observed that, with many other forms of signals, a metal detector can completely miss detecting banknotes. In instances like these, detecting cash becomes too tricky for the machine.

Quotee quotes the exact words by the inventor of metal detectors, capable of detecting money; Chen speaks out on this issue. He says, “If we do consider a real situation, sometimes the signal strength can be way too noisy. To fix this, some kinds of digital signal processing can be done.

He further adds, “The results in hand are published, and it was done from a feasible point of view, and I can see that there are various spaces to make the machine even better than it is now.” Christopher and Chen, are both set to take their creation to a higher level altogether. 

There can be sources that extract magnetic waves and hamper the signal quality of a metal detector. Hence, the metal detector can give inconsistent or false readings during such instances and can detect no cash due to these signal disruptions. However, these are very rare in reality. 

Adding one more tool for enhancing the signal quality of the metal detector can lower down these signal disruptions and help it give a correct reading. Scientists of Cambridge University are trying their best to make this machine more efficient compared to it now


This article shows that the conclusive answer to “Can a metal detector detect money?”

Yes, Metal detectors can detect cash and count the exact number of notes, the precise amount of money one is carrying on him/her only if the printing ink in the banknotes is magnetic. 

However, there are still points where this incredible machine can be even more developed. For example, the signal or sensitivity of this machine becomes stronger when the amount of money is way too much (which serves the purpose of the metal detector).

Still, the signal considerably decreases when the notes become fewer. We are sure that the mammoth pace at which technology is advancing in this modern generation, metal detectors will not only shed off the flaws it has but will also come with even delectable features. Probably a few years later, it will be able to detect something which is still beyond human thought.

Avatar for Jaren Helms

Jaren worked for over a decade in the industry as a Package Handler. He started his career with FedEx but he later also worked with companies like USPS and Deutsche Post.

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