Counterfeit Currency Detector
Using Spectral Properties.
Parthiban Sundararaj
1RV09EC056
Nishant Yadalam
1RV09EC051
Ashay Panshikar
1RV09EC014
Muthukumar Thangarajan1RV09EC047
OBJECTIVES
• To create a portable, affordable, handheld
device that can be used to detect counterfeit
notes based on the parameters as set by RBI.
• There is a growing demand for such a device
as inflow of such notes has increased
drastically.
• If made available to every individual then we
could tap it at the source.
Parameters to identify counterfeit
currency
Parameters
1.See through Register
2.Watermark
3.Optically variable ink
4.Fluorescence
5.Security Thread
6.Intaglio Printing
7.Latent Image
8.Micro Lettering
9.Identification Mark
10. Transparency due to composition
11.Year of Printing
Working Principle
• The project consists of testing a note
based on 2 distinct parameters:
– Based on a note’s transparency to IR radiation
– Based on a note’s reflectivity to UV radiation
Transparency to Infrared Radiation
• The composition of a real note, which is made
of a fixed formula of specific fibers, has a
predefined level of transparency.
• This property is not replicated in a fake note.
• When infrared light is incident on the note,
only a fraction of it will pass through due to
the note’s opacity to the radiation.
• The value obtained for a real note was 93mV
Transparency of a real note
Say the amount of light transmitted is ‘X’.
And the amount of light received is ‘X-x’. This
value of X-x is quantized into 3 values by the
ADC.
When transmitted light=received light, all the
3 LEDs switch on.
Reflectivity to UV Radiation
• When seen under UV light, the fluorescent ink
glows and is visible to the naked eye.
• This is a First Line Indication method.
• The RBI strip appears green and the notes
serial number glows red.
• In this project this method is used
simultaneously with Second Line inspection
methods to ensure higher accuracy
Effect of UV radiation on a real note
Block Diagram
Circuit Diagram of LED Array
• The infrared receiver and transmitter are
biased using resistors of 2.7kΩ and 470kΩ as
seen in the diagram.
• The amount of light received by the receiver
when a note is place in the middle is
quantized into a digital value by the ADC and
is displayed by the LED array.
• The voltage across each 330ohm resistor was
found to be 1.1V and a current of 3mA.
UV Tube Driver Circuit
• The circuit consists of 3 capacitors, diodes
and a resistor per tube. The power supply to
the circuit is a 230V AC power supply.
• The voltage required across each UV tube is
48 volts, minimizing the power surge across
the tubes. The voltage across the tube is then
converted to UV radiation which is incident
on the currency note.
• The 6800pF capacitor acts like a DC battery
across the UV tube, which scales down the
voltage to 120V from 230V power supply. The
rating of these capacitors is 400V.
• The diodes (IN4001 is used to handle the high
power) are used to protect the circuit from
reverse current, which could potentially cause
the circuit to malfunction.
• They can withstand up to 1000V of reverse
voltage, which is required for the application.
• The 1uF/400V capacitors in the negative
terminal of the tube are used as a voltage
doubler, to double the voltage to the negative
terminal after it has been scaled down by the
resistor.
• Each phase of the circuit can take up to 160
micro amperes at 240 volts without
malfunctioning.
Challenges Faced
•The dispersion of the transmitted IR radiation
•Interference of sunlight
Second Challenge
An RLC oscillator was used to drive the UV tube, but
had the following issues due to which we had to
change:
•Large amounts of heat was generated by the
Ferrite Core
•Even with two heat sinks being used, the heat
was not effectively absorbed
•Noise (high frequency) was generated by the coil,
due to which a substantial amount of energy was
lost
Algorithm
Transparency of Notes using Infrared
1.
2.
3.
4.
5.
6.
7.
8.
Initialize port A4 to A7 as digital output.
Initialize port A0 as analogue input.
Write Vcc and ground to pins A1 and A2.
Set baud rate to 9600.
Write high to the IR transmitter pin.
Repeat continuously from steps 7 to 10.
Read the analogue input from port A0 and assign it to variable ‘a’.
Calibrate the value of ‘a’ between the highest and lowest values (h and l)
received by the receiver.
9. Map this value to a numerical from 1 to 8 using the formula :
b=8*(a-l)/(h-l).
10. Use the value ‘b’ to set the corresponding number of LED’s to high value.
Code
void setup()
{
pinMode(A1,OUTPUT);
pinMode(A2,OUTPUT);
pinMode(6,OUTPUT); // digital output from the ADC
pinMode(7,OUTPUT);
pinMode(4,OUTPUT);
pinMode(5,OUTPUT);
pinMode(A0,INPUT); // analogue input to the ADC
digitalWrite(A1,HIGH); // Vcc
digitalWrite(A2,LOW); //Ground
digitalWrite(4,HIGH); //common ground
Serial.begin(9600); // Set baud rate
}
void loop()
{
int a,b;
a=analogRead(A0); //assign the analog input to ‘a’
delay(300);
b=constrain(a,250,850); //calibrate the highest and lowest values of ‘a’
Serial.print(a);
Serial.print(" ");
a=map(b,250,850,1,4); //map the value of ‘b’ from 1 to 4
Serial.println(a);
switch(a) //using the value of ‘a’ choose which LED’s to glow
{
case 1: digitalWrite(5,HIGH);
digitalWrite(6,HIGH);
digitalWrite(7,HIGH);
break;
case 2: digitalWrite(5,LOW);
digitalWrite(6,HIGH);
digitalWrite(7,HIGH);
break;
case 3: digitalWrite(5,LOW);
digitalWrite(6,LOW);
digitalWrite(7,HIGH);
break;
case 4: digitalWrite(5,LOW);
digitalWrite(6,LOW);
digitalWrite(7,LOW);
break;
default: digitalWrite(5,HIGH);
digitalWrite(6,HIGH);
digitalWrite(7,HIGH);
}
}
Future Ideas for Expansion
Infrared Reflection Using Watermark
• The watermark of a currency note, due to its
chemical composition has a specific reflectivity
• When infrared light is incident on the watermark
portion of a real note, it absorbs the infrared
light.If the light received is more than 2.17V then
the note is might not be authentic.
• After the light is received, it is amplified by an OpAmp and then sent to the processor which checks
if the value received is above the threshold
voltage, if it is, the note is said to be fake.
Circuit Diagram
Algorithm
1.
2.
3.
4.
5.
6.
7.
8.
9.
Initialize analog input pin
Initialize the sensor value and sensor threshold
In the setup function
Set baud rate to 9600
Declare pin 13 as output pin
Calibrate sensor threshold
Read value from analog pin.
Compare it with the sensor threshold.
If sensor value is much greater than sensor threshold, declare the
note as fake and beep buzzer.
10. Else leave it as low
11. Loop steps 7-10 continuously
Source Code
Results
Conclusion
• Fake currency poses a grave threat to national security
and could also result in economic destabilization.
• We have attempted to make the device as portable and
cheap as possible, to be able to be marketed to the
common man. This ensures an effective defense
mechanism against the fake currency producers.
• Future scope of this project lies in including more
parameters given by the RBI bank for real currency
notes which can make the system more reliable and
efficient
References
1.
2.
3.
4.
M.M.Joshi, Ram.P.B, Gautum.M, Harish.K.S, Hari.N.B, Saroj.B,
‘Fake Currency Detector Using Visual and Reflective Spectral
Response’, United States Patent, Patent no.: US 7684607 B2, 2010.
Trupti.P, Swapnili.K, ‘A Novel Approach of Embedded System for
Indian Paper Currency Recognition’, International Journal of
Computer Trends and Technology, 2011.
Kalyan.K.D, Sultan.U.A, Md. Shahjahan, Kazuyuki.M, ‘A Paper
Currency Recognition System Using Negatively Correlated Neural
Network Ensemble’, Journal of Multimedia, 2010.
Ankush.R, Biswajit.H, Utpal.G, ‘Authentication of Currency Notes
through Printing Technique Verification’, 2010.
Thank You
Choice of Ferrite Core
• Low electrical conductivity of ferrite which
helps prevent eddy currents
• Low losses at high frequencies
• High magnetic permeability
Capacitors
• Two capacitors of ratings 5nF and 3nF were
used in the resonant circuit
• f= 1/2π√ (LC)
• ~8 MHz (Sub UV)
Power Transistor CTC1351
• Low output resistance
• They can deliver large currents to the load
• Good junction insulation to withstand high
voltages
• They are able to dissipate heat very quickly
• As most heat is generated at the
collector/base junction, the area of this
junction is made as large as possible.
• Black Light tube specs.
• 368 to 371 nanometre emission peak