Decoding the Unique Identifiers

As I mentioned in my previous post, I am able to read the ID’s of both the cards that came in my kit, however these ID’s are raw. We can decode these into different formats.

By reading in the code byte by byte the code is read, by default, in decimal (DEC).

For those who haven’t met the different number base’s, in our normal day to day lives we use the decimal number system which is base 10, ie 10^0 = 1, 10^1 = 10, 10^2 = 100 . . . Base 10 only uses combinations of the numbers 0 to 9. Other common bases include:

Hexadecimal, base 16 ie 16^0 = 1, 16^1 = 16, 16^2 = 256 . . . Base 16 uses a combination of 0 to 9 and A to F to represent 16 digits.

Binary, base 2 ie 2^0 = 1, 2^1 = 2, 2^2 = 4 . . . Base 2 uses only two digits, 0 and 1.

So using this we can adapt what is sent using the Serial.print command by writing the value or variable we want to send, followed by BIN for binary, DEC for decimal, HEX for hexadecimal, as well as others that I haven’t covered.

so using

int val = 0; // variable to store the data from the serial port

void setup() {
Serial.begin(9600); // connect to the serial port
}

void loop () {
// read the serial port
if(Serial.available() > 0) {
val = Serial.read();
Serial.println(val,DEC/HEX/BIN); //use one Base as appropriate.
}
}

We can read the value in any base system supported by Arduino.

DEC
2 53 49 48 48 55 66 69 65 52 50 56 50 13 10 3
2 53 48 48 48 56 70 65 52 66 56 67 51 13 10 3

HEX
2 35 31 30 30 37 42 45 41 34 32 38 32 D A 3
2 35 30 30 30 38 46 41 34 42 38 43 33 D A 3

BIN
10 110101 110001 110000 110000 110111 1000010 1000101 1000001 110100 110010 111000 110010 1101 1010 11
10 110101 110000 110000 110000 111000 1000110 1000001 110100 1000010 111000 1000011 110011 1101 1010 11

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RFID and a LCD

After a long wait my delivery arrived with the new RFID kit and 16×2 LCD.
So first thing to work on was the LCD, and what better to start with than “Hello World”! Having not used the Arduino for some time I started with the LiquidCrystal HelloWorld example and then worked from there.

 

#include <LiquidCrystal.h>

// initialize the library with the numbers of the interface pins
LiquidCrystal lcd(12, 11, 5, 4, 3, 2);

void setup() {
// set up the LCD’s number of columns and rows:
lcd.begin(16, 2);
// Print a message to the LCD.
lcd.print(“hello, world!”);
}

void loop() {
// set the cursor to column 0, line 1
// (note: line 1 is the second row, since counting begins with 0):
lcd.setCursor(0, 1);// print the number of seconds since reset:
lcd.print(millis()/1000);
}

After checking that I had everything working correctly using HelloWorld, I started experimenting displaying variables and changing the location of the cursor.

Next to work on the RFID module.

Not having an example to start with, I did a little searching online to find an excellent Instructables post. From this post I learned that with the RFID tx pin connected to the arduino’s rx pin, you can you the Serial.read() command to read the unique identifier.

/* RFID ID12 */
//RFID tx pin –> arduino rx pin

char val = 0; // variable to store the data from the serial port

void setup() {
Serial.begin(9600); // connect to the serial port

}

void loop () {
// read the serial port
if(Serial.available() > 0) {
val = Serial.read();
Serial.write(val);
}
}

Now that I was able to display text on the LCD and also read the values of the RFID tags, the next logical step was to combine the two together!

Now working on my own code, I set out to get the LCD asking for the card to be scanned, and then displaying the number of the card.

#include <LiquidCrystal.h>
LiquidCrystal lcd(12, 11, 5, 4, 3, 2);

void setup() {

lcd.clear();

// put your setup code here, to run once:
Serial.begin(9600);
lcd.begin(16, 2);
lcd.print(“Please Scan Your”);
lcd.setCursor(0,1);
lcd.print(“Card:”);

}

void loop() {
// put your main code here, to run repeatedly:
if(Serial.available() > 0) {
// wait a bit for the entire message to arrive
delay(100);
// clear the screen
lcd.clear();
lcd.print(“Your Card is”);

lcd.setCursor(0, 1);
// read all the available characters
while (Serial.available() > 0) {
// display each character to the LCD
lcd.write(Serial.read());

}
delay(1000);
lcd.clear();
}
}

Arduino goodness!!

Brought myself some new toys for my Arduino today.
I’m looking forward to using the LCD as an interface, and displaying data, maybe eventually a twitter feed display.
My second purchase was a RFID starter kit that the good people at Sparkfun produce. My University ID card has RFID in it so should be interesting to read the data off that, maybe use the LCD to then display that data.
I’ll update everyone when i’ve started working with them.

LCD Add-On for SIK

Looking forward to using an LCD with my arduino

Sparkfun RFID Starter Kit

Looking forward to this arriving