Portable Banknote Recognizer

[atmega64]

Hi everybody,
I am trying to build a portable and inexpensive banknote recognizer. I found many articles about banknote recognition but they are all based on computer. Seems there are some good devices like this:
**broken link removed**
Could you please suggest me some idea about how does it work?
Thanks a lot

 

[Misterbenn]

I'm not sure how the device you link to works, also i'm in the UK so not familiar with US notes (btw you dont mention your location); but from: https://www.wikihow.com/Detect-Counterfeit-US-Money

Plastic strips in high-denomination bills should glow a specific color.

• The $5 dollar bill should glow blue; the $10 bill should glow orange; the $20 bill should glow green; the $50 bill should glow yellow; the $100 bill should glow pink.
• If your bill remains white under a black light, it is likely a counterfeit.

So that's how I'd do it, presuming the plastic strip is always XXmm from the edge you could set up a color recognition circuit.

I was going to ask why you would even need such a device but having looked at the link you gave this is clearly an important device for visually impaired people - shame it cost so much.

 

[Misterbenn]

another interesting lead on this topic
https://en.wikipedia.org/wiki/Currency_detector

 

[atmega64]

I'm not sure how the device you link to works, also i'm in the UK so not familiar with US notes (btw you dont mention your location); but from: https://www.wikihow.com/Detect-Counterfeit-US-Money


So that's how I'd do it, presuming the plastic strip is always XXmm from the edge you could set up a color recognition circuit.

I was going to ask why you would even need such a device but having looked at the link you gave this is clearly an important device for visually impaired people - shame it cost so much.

Dear Misterbenn,
First of all thank you very much for your help.
I didn't have any idea about plastic strips in U.S currency. If iBill really works based on this simple principal, so it is such a shame it costs so much.
Anyway, I am from Iran and Rial is our currency. Now I will search for such properties in Rial. I have to mention my purpose of this project is value of money detection NOT a fake detector.
Here, visually impaired people and blinds really suffer from lack of such a device. I will be greatly appreciated if any of you help me.

 

[Misterbenn]

Ok so we might struggle with available information about the Rial,
I used https://en.wikipedia.org/wiki/Iranian_rial and looked at the Current (Imam Khomeini) Series (1992), are they the notes you're talking about.

Looks like you have a colored denomination system so that might be one way of working.
other than that currency readers seem to use either magnetic or imaging methods.

 

[atmega64]

Yes, we use Current (Imam Khomeini) Series (1992). Also you can check this:

http://banknote.ws/COLLECTION/countries/ASI/IRN/IRN-CBIRI.htm

Please consider ND (1992-2014) Issue.

You are right. Looks like I should try a device based on a color recognition scheme. There are some color sensors like bellow (sorry this site is in Persian but I think you can see it):

http://roboeq.ir/products/category/73/

At that page, after you selected any sensor, there is a datasheet for it with a PDF icon.

Using of such sensors is only an raw idea and needs more study. If I try one of mentioned sensors, One challenge might be designing a good sweeping mechanism. But my challenge is its cost, because I want to build it as cheap as possible till every one could afford it.

 

[blueroomelectronics]

Most countries have raised dots on the currency.

Also there is money recognition software for some smartphones.

 

[atmega64]

Dear Blue,
Thanks for participating in this post.
Unfortunately, Rial does not have such dots, however I think that is not a good method to help impaired people because dots will smooth after a short time.
About smartphones, as you know all of people can't afford them, beside I think cell phones as a money detector are not reliable. We need a device that will be portable, low power consumption and very reliable.
My friends, Just think about impaired people and blinds who want to start a simple business like salesman or even in every day activity that is very easy for us but extremely hard for them. A money detector can really change the life of them.

 

[Oznog]

Just FYI there is a long ongoing "arms race" between bill readers and counterfeits/scammers. Long history to read up on.

Ever wonder what the color-changing "counterfeit detection" pen thing we use is? It's an iodine solution that reacts with the starch present ordinary paper but not banknote paper. But a counterfeiter can simply go with less common but widely available starch-free paper. Potentially a chemical additive could be used too, that would spoil the iodine's reaction. This is not considered a reliable test nowadays.

Currently, the magnetic and fluorescent stripe tests are not totally undefeatable, and this, or any test method can and almost certainly will be defeated.

 

[Misterbenn]

As the OP mentioned this is not a fake detector just a useful aid for the blind.

If the colors are strong enough on the Rial then this might work. otherwise it will have to be magnetic, although we've no idea if the Rial used magnetic Ink.

 

[atmega64]

Here, Only cheques are using of MICR system (Magnetic ink character recognition), So unfortunately magnetic ink idea is not applicable.

 

[KeepItSimpleStupid]

There are "bill validators" and they were not built on the "stripe technology", but some sort of pattern. Where, I'm sure that's the validates secret.

 

[Brevor]

There are "bill validators" and they were not built on the "stripe technology", but some sort of pattern. Where, I'm sure that's the validates secret.

I worked in the banknote validation industry for over 15 years. And yes you are correct they keep it VERY SECRET.

 

[KeepItSimpleStupid]

Interesting: https://www.ribaotechnology.com/product/252-currency-sorter-bcs-150-bcs-150-04f8/ Although this is aimed at counterfeit detection too.

My guess one could use "facial recognition" or scan the areas where bill denominations appear for just denomination detection. I'm thinking US bllls at this point.

It looks like for US currency long wave UV can basically distinguish all bills by reflected color but the $1 and $2.00 bill. **broken link removed** making a bill identifier pretty easy. The $2.00 bill is rarely seen. So, by elimination if it's not the others, it's a $1.00 bill. The older bills have effectively been removed from circulation. You might be able to put an extra check for the $1.00 bill.

 

[ronsimpson]

In many countries you can tell by color how much money. There is probably one spot to look at.
There are some simple color sensors.
https://www.sparkfun.com/products/12829
https://www.sparkfun.com/products/10904
One of these and a $2.00 computer.

Also see:
https://www.digikey.com/product-search/en/sensors-transducers/color-sensors/1966897?k=color sensor

Last time I did something like this I used TCS3200 or one of its brothers along with a very small computer.
For blind people I can see a small speaker added.
For 1 = beep. 2=beep beep, 10=BEEP, 20=BEEP BEEP, 100=a song "oh happy day"
A very simple computer chip can make some complex sounds. Probably not words but maybe.

 

[crutschow]

You could also use a sort of Morse code technique, such as long and short beeps or beeps with pauses in between.

 

[atmega64]

Dear KeepItSimpleStupid, Brevor, ronsimpson and crutschow,

Thank you all for your time and consideration. I am sorry for delay because I didn't receive an notification e-mail.

Looks like I should try a device based on a color recognition method. In this case, we need a mechanical system to scan an area. I think using of such systems are not cost effective and most people can't afford it. In addition, moving parts can always causing problems. I found an interesting paper:

https://www.researchgate.net/profil...n_impaired/links/0f3175348db0cb9835000000.pdf

That method looks very simple and inexpensive. What do you think?

 

[dougy83]

That method is only useful if the notes are sufficiently different colours. There may also be a problem with their experimental setup; I only briefly looked, but it appears that their dataset uses multiple scans of the same note, and these scans are in both the training and test sets (this will generally increase the performance). So basically, YMMV for your set of bank notes.

Another method, although more complex, is to use a CMOS camera and some custom optics with some image processing for the classification. The optics would be a mirror and close-focusing lens. You can then use any of the common pattern recognition methods to extract a features from the image for classification.

A cheaper method might be to use compressed sensing and an array of LEDs to provide random illumination and also to read back the sum-illumination (each sensor will reflect the weighted sum of the interaction of the current illumination pattern and note). The LEDs can be used as emitters and detectors, and you can use a variety of LED colours to get the different colour responses of the bank notes. ref https://www.google.com.au/search?q=single pixel camera You don't actually have to recreate the high-resolution image, but can use the scaled sum-illumination values directly in an extreme learning machine (ELM) or similar classifier (because the sum-illumination values are already random projections of the input signal, you can skip the random projection step in the ELM).

 

[Reloadron]

While this may be off topic it is something I have found interesting. Hard Rock Cafe recently opened a Rocksino just up the road from us. While new casinos have sprung up in Cleveland the Hard Rock focus is strictly slot machines. Thousands of the things.

Every slot machine accepts US denomination $1, $5, $10, $20, $50 and $100 bills and every machine knows if the bill is a counterfeit. When I say the machine knows it knows and if a counterfeit is run within a few heartbeats casino security is right there, not to mention you are on video surveillance. Those bill acceptors are just a small part of the entire slot machine so I am sure any slot machine manufacturer has mountains of those modules. Never gave much thought to how they actually work but they do work and work well.

Me? While I confess to playing a few machines my big draw at the casino is the Harvest Buffet and Kosar's Steak House (Bernie Kosar, former Cleveland Browns quarterback) as well as the usual Hard Rock Cafe and also they book some great shows and entertainment.

Ron

 

[ronsimpson]

Here are some pictures. I could build a color scanner in a pin that you wipe across the paper. By looking at the average color of the paper you will know much money. I think "moving parts" are a bad idea. Keep It Simple!

I looked at IRAN money and the colors might not work in all cases.
This should be a cellphone application very easy.