I'm pretty new to micro's, I'm trying to build an automatic door unlock-locking system using RFID. I've searched and found a lot of info, so much in fact that I am now thoroughly confused! Can someone point me in the right direction? I'm not looking for any hand holding, just some info that relates to my specific application.
There is a link to the data sheet on the page. No matter how I wire it up, or which example I try I can't get it to work! Has anyone used this reader before? Any help appreciated.
void loop()
{
for (int i=0;i<=13;i++){
Serial.print(mySerial.read(),BYTE);
}
Serial.println(" <<You may enter BITCH!");
delay(1000);
}
My prob is I figured the LED would blink or light up when it read a tag but it dosen't and the datasheet doesn't mention how to implement it. There is a 3 pin header just for this. My plan is to slowly build on the example code. I haven't even gotten to the multiple cards or unlocking the door and I'm stuck! this is going to be a long project!
The center pin gets connected to +5V, the pin away from the end of the card gets connected to Gnd. The pin closest to the end of the card gets connected to the long leg of the LED. The short leg of the LED is connected to Gnd. The LED then blinks whenever a tag is recognized.
Yes I have the datashhet which lists the pinout, do I still need a resistor? Perhaps I need to remove the resistor? I'll try that, if I blow an LED oh well!
Ok Well I thought a had used a resistor, but had forgotten to include one oops! but even so a closer inspection revealed that it in fact was lighting up just very very dim. Probally because i'm not using a wall wart.
New problem, my three key FOB's have their number printed on them. The two credit card's don't.. when the number for the keychain FOB is printed on the serial window it's toally diiferrent than what's on the FOB, with two box symbols, one at each end.
How do I figure out the numbers for the credit cards???
This implies that it is a non printing ASCII character. If it is at each end it is likely to be a start of block character and the one at the end a check sum.
To test, print out each character in hex (or decimal if you must).
The number printed on the fob is the number you enter into an access control system. The number seen in the field of an RFID reader may be a different number but one must be able to be derived from the other otherwise the system would not work.
Some readers like those from PAC employ a scrambling algorithm inside the reader to convert the number seen in the filed to the number used in the access control system. This is a "one way" algorithm, that is while a unique input produces a unique output you can't take an output and derive a unique input from it.
So from one example of an input and output there is no way I can reverse engineer a solution but there is a relationship that can be found given enough information. That's what I meant by:-
It is a function of the reader not the fob, I know it is not the case with all readers only some of them.
Well give me all the figures of the RF field and I will see if I can work out a relationship. Is the RF field number hex or decimal? Just because there are no numbers above A doesn't mean it is not hex.
It could also be that there are some bits that are check sum or parity bits and that tends to throw you off as well. Do you know what make it is?