rfid emulator - how to clone rfid card, tag ...

by:CTECHi     2019-12-28
Where did this idea come from?
The idea of creating an RFID Simulator comes from the idea of creating an environment for developing and experimenting with different RFID applications.
The goal of this article is for engineers amateurs and electronics enthusiasts who like to experiment with different RF devices and face challenges.
Later I realized how useful it is for schematic applications in our daily lives, and how useful it is to develop schematic for backup of existing RFID cards, so your access card always has backup
Suppose you have a spare key for your home or car.
If you lose the RIFD card, you will use the RIFD simulator for backup, and you will not be able to lift without a barrier to the garage or sitting outside the office.
When possible, at a convenient time, you can tell the person who supports the access control system that your card is lost and wants a new one.
With the RFID emulator, you can back it up and use it in subsequent similar requirements.
The most useful thing is that the RIFD simulator does not confuse the activities planned for the day.
You can buy the assembly kit on my website and see another interesting item: www. kukata86.
If you have other ideas or have developed a better system with more options, please share it with us on my website and let us make this project better and better.
The creators and distributors of the program, as well as the materials needed for the construction, will not be responsible for the malicious behavior of malicious individuals tampering with the equipment!
Everything about this device and the attached article is for educational and experimental purposes.
Take the risk of using it yourself!
Device control interface.
There are two buttons on the board.
They are connected to the GP2 and GP3 pin inputs of the processor.
Two capacitors (C5 and C6)
Connect in parallel with the key to prevent any interference feedback.
Pay attention to the GP3 pull resistance (R5)
It\'s not GP2 because it uses software programming.
Processor series PIC 12F * In addition to gp3, software-controlled pull resistors are built on each I/O line. 1K resistors (R3 and R4)
Independent I/O segments of the capacitor.
This is what ICSP programming needs to use.
Without this separation, connecting the ICSP programmer or debugger will load the capacitor GP3/MCLR/Vpp, thus preventing the ICSP programmer from sending the required voltage and the chip will go into programming mode.
Nevertheless, my suggestion is to program the chip advanced programmer before welding or before placing the capacitor on the board to ensure the programming is successful.
Because this is a test, continuous development of the project, if the problem is on programming or hardware, programming will hardly fail, so at least you can safely follow the prompts in the software section below.
The information shows the \"successful programming\" LED using a series 470 ohm resistor.
Be careful when selecting LED for your project.
Most common SMD LEDs have a current of up to 8 mA, which is usually more expensive than other devices.
Bring more powerful LED (
Bright, white, blue)
Or different from smd.
The LED assembly may consume too much power to exceed the power of the antenna itself, which may result in a drop in the supply voltage below the minimum threshold scheme and thus not working properly.
The power issue is how to get the voltage best and most efficiently from the carrier frequency of the 125 khz RFID reader and how to use it to power the system. I. e.
Make a passive detector without the need for an external power supply.
Use schematic diode-
The bridge from simple low voltage silicon rectifier diodes has a very large loss.
These diodes have a voltage drop of about 0 on him.
6 v, when every half cycle of the current becomes normal, we will lose 1 through two of these cycles. 2V.
The experiment shows us the following results.
When using diodes
The bridge circuit consisting of four Schottky diodes saves more than 600 mV, which is a better choice. Used 1N5819 (with Vf = 0. 2V @ 10mA)
Perfect for this.
In the bottom wave chart, please note the difference between using a Schottky diode or a normal diode when introducing carrier frequency.
Blue: = 2. 03V Green: = 1. 36 V yellow: Max. = 2.
27 V Б я л: = the GND blue line displays the power signal with a MOSFET diode.
The green line does not have a Schottky diode.
The yellow line is the signal induced when the coil arrives (GP5)processor.
As pointed out in use, it can save about 0 compared to ordinary diodes. 6 volts.
Several capacitors have been added to filter the supply voltage. Electrolyte (C4), Tantalum (C3)and Ceramic (C1).
Not all of this is necessary, but helps to significantly reduce peak harmony waves, such as LED lighting or using built-in
Generator in 8 Mhz processor.
In most cases, the voltage induced in the coil cannot exceed 6 v and will not damage any elements.
But sometimes under certain conditions
In a strong magnetic field or sharp magnetic coil (
Slide to the receiver suddenly)
Can form a peak above the maximum voltage that can kill the CPU.
In order to prevent the risk of damage caused by the surge, we applied the following schematic diagram.
If the voltage is less than 5. 1 V Zener diode (D1)is blocked.
The base of the transistor (Q1)
It\'s \"GND\" and it\'s also blocked.
When the power supply voltage skips 5. 1V.
Zener diodes open and unlock transistors respectively (Q1). On (R7)
A voltage drop sufficient to load the power of the coil is formed to reduce the power supply voltage to less than 5. 1V.
The 5-pin connector displayed by the ICSP connector provides easy access to the pins of the micro-controller.
It can be used to program or test I/O on the chip.
The connector has the same pin connection as programmer PicKit2, but you can use other JDM programmers as long as you follow the correct pin connection.
Select the useful flag mentioned above to have the type of card that can accept the data sent by the reader.
Typically, this operation is used to write data to the card processor (
Programming cards for our choice).
The way the card reader transfers data to the card memory and the card reader sends the data-
The modulated RF carrier accepted by the antenna.
In order for our simulator to be able to read and process this information, it is necessary to create a circuit to read, decode this information and send it to the processor.
Later it was recorded playing on its own.
To do this, the carrier frequency is demodulated to remove only useful signals, and the easiest way for us is to use the \"envelope detector\" diode (D4)
Miss the positive component of the pulse frequency and load capacitor (C7)
When the amplitude of the carrier increases.
When the amplitude of the carrier drops the capacitance (C7)
Discharge by resistance (R8)(
Diode to prevent power discharge).
The signal we need formed by the edge of the carrier frequency is the modulation signal that contains the data on the card.
Green Line: modulation carrier input yellow line of envelope detector: output signal of modulation signal detector at the output of envelope detector (
Cross-coupling capacitance (C8)
As a permanent component of isolated strain.
Green Line: Before the constant component yellow line is released: after the constant component white line is Untied: GND erence: 0. 5V/V-div 0. 4ms/H-
As can be seen from the wave diagram, divAs is negative due to the release of the constant component of the comparator input signal (
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