How to make a copy of the key for the intercom at home. A simple do-it-yourself intercom key duplicator Do-it-yourself intercom key copying

Everyone knows that any mechanism deteriorates over time, and it has to be changed, especially for elements subject to frequent physical exertion.

Electronics in this sense is more reliable, and if it is well protected electrically, it can last quite a long time.

The loss of keys from a mechanical lock is often associated with the replacement of the latter. Losing an electronic chip, it is enough to make a copy of it using.

How a duplicator is arranged and works

What models and types of key duplicators are

All duplicators of intercom keys available in nature can be classified into three different types:

1. Programmers for flashing contactless keys tmd;
2. Duplicators for making copies of contact intercom keys;
3. A universal type of duplicators that can reflash any kind of intercom chips.

Each of these types of devices have their modifications.

Contactless Duplicators

Among them there are three modifications of devices.

The first modification includes programmers that make the RFID standard EM-Marin, HID and Indala (tmd duplicators), the second modification supports the Mifare standard, the third modification of the duplicators works with keys of the TECH-COM or TKRF standard.

Contact type devices

Devices are presented in two types. The first type is designed to work with dallas contact type keys, the second type of programmers duplicates type keys or.

The Dallas chip has a hexadecimal code, and the digital one is flashed with a protocol type code, which is large in size.

Universal key programming devices

Universal intercom key duplicators, in addition to being able to create a copy of any digital chip, have a number of additional functions:

• Ability to update;
• The presence of a memory base;
• Code generation.

Considering the first function, it must be said that when new modifications of keys with the original encoding are released, the base of the programming device can be flashed for these chips, and it will be able to make copies of them.

The second function makes it possible to clone keys without the original. That is, after the first flashing, the chip code is simply written to the device base and reproduced as needed.

The third function allows you to flash keys with original codes, for example, for company employees, each of whom must have their own personal access code to the lock. Then you can track the number of visits to a particular object by a specific person.

What you need to make a do-it-yourself intercom key duplicator

When making a key copier with your own hands, you can take the Arduino module as a basis.

The element base that will be needed to manufacture the device:

1. The microcontroller of the “Arduino Nano” type is the main “brains” of the device, where information is processed and data is recorded;
2. RFID RC522 board, which acts as a module that reads codes and redirects information to the microcontroller;
3. Piezoelectric type buzzer;
4. Two LED elements for the monitor;
5. Two 330 ohm resistors;
6. Keyboard block type 4X4;
7. I2C type liquid crystal display adapter (LCM1602), which acts as an LCD converter to an Arduino-compatible format;
8. Liquid crystal display type LCD16X2BL.

The liquid crystal screen is connected to the contact group of the adapter using sixteen pins. On both modules, the contacts are numbered.

Next, power wires are connected to the display adapter from the rf ID RC522 module: red - to the VCC (+) contact and black - to the GND (common) contact. The control wires are soldered to the SDA and SCL pins. LED elements are installed in tandem with current limiting resistors.

The principle of flashing keys

Intercom chips, which are in the form of tablets and whose surface must be applied to the intercom contact, do not contain magnetic elements inside.

The circuitry of the device is based on the use of non-volatile memory (in other words, ROM).

In such a memory, a sequence of characters of a digital unique code is written.

The principle of rewriting such keys is that the tmd duplicator reads the code and recreates it on a pure chip platform.

The RFID system is built on the transmission of a code not by contact, but by a certain radio frequency.

The key circuit contains an oscillatory circuit. If it is excited, the data from the memory will be transmitted to the reader through space.

Such an excitatory signal will be a signal coming from the antenna of the intercom or duplicator. Otherwise, the principle of how to copy the code into memory, its further reproduction is no different from the principle of operation of the contact device.

The only difference is that programmers can only store and play back a certain type of digital signal. The exception is universal devices that can be programmed to work with any type of digital data.

Conclusion

Making chips for an intercom with your own hands can be not only a solution to the problem of losing personal keys, but also an opportunity to build your business on it.

To begin with, you can make a simple intercom key copier for the most popular “blanks”.

The most important thing is that such earnings do not require large initial investments, and services will always be in demand, especially in large cities.

Video: Do-it-yourself intercom key duplicator

As a means of protecting the front doors of houses from uninvited guests, they are often used.

To enter the house, you need to use a special key that owns its number, which acts as an identifier. According to this number, the electronic system recognizes “friend” - “alien” and lets the owner into the house.

Why do you need a key duplicator?

Sometimes it happens that you need to make a copy of the intercom key. The Arduino Intercom Key Duplicator may be needed if one of the keys in the kit was lost, an additional key was required, or the old key failed.

Naturally, in this case, you can use the services of specialized workshops, but you can perform this procedure yourself. This option will be of particular interest to those who understand electronics and have the practice of using modules.

On the Internet, there are many different projects on how to make a copy of the key to the intercom with your own hands using Arduino. The task is not as difficult as it seems at first glance.

You just need to find out the ID number of the original key and assign it to a duplicate. The intercom system will recognize such a key as "own" and will open the door.

The procedure for reading from the key, as well as writing an identifier to it, is performed using only a single-wire 1-wire interface. Thanks to this, the schematic diagram of the future duplicate of the intercom key is quite simple.

Below, all the steps will be considered step by step, through which, in a minimum time and with minimal financial costs, you can independently make a duplicate of your key to the intercom.

How to make an Arduino-based duplicator

To make a duplicator of intercom keys on an Arduino Uno or Nano, you need to carry out separate work with the hardware of the future device, and then with the software.

Hardware

You can create a compact duplicate of the key to the intercom using the Arduino Nano module, which is placed in a case from a non-functioning USB hub. The key in this design is quite compact and easy to use.

A USB cable is used to connect the device to the COM terminal, as well as to supply power to it. A non-latching button should be installed on the key duplicator body, which will be used in cases where it is necessary to switch the “read” / “write” / “restore” modes.

Also, an LED indicator is displayed on the front panel of the case, used to visualize the state of the key (in which of the 3 modes it is), as well as a contact pad that acts as a key reader.

The electronic circuit of the device of the future duplicator is distinguished by its simplicity. It includes a 1-wire data exchange line, to which + 5V is supplied through a transistor, the value of which can be 1 ÷ 4.5 kOhm.

The best option would be the average resistor value of 2.2 kOhm. The mode LED is connected through a limiting resistor of the optimal rating. The mode switch button is connected to pins D2 and GND.

Software part

In the firmware of the device, you can leave the part of the code unchanged that is responsible for the processes of reading and writing data to the dongle via the 1-wire protocol, as well as the part that ensures the operation of the module.

The rest of the code is rewritten for our own needs, using the standard Arduino OneWire library for this. You can write a sketch for programming the Arduino module used for the key duplicator yourself or find a ready-made version on the Internet that you can optimize for yourself.

The created and programmed module based on Arduino will allow:

1. read from the original key its ID, followed by overwriting into the prepared "blank" of the key;
2. write down the universal ID that is set in the sketch;
3. provide protection for accidental ID overwriting with an incorrect value;
4. restore unreadable keys after an incorrect entry of the identifier;
5. enter the ID number manually;
6. support operation without a COM terminal provided that there is a 5 V DC power supply, which is supplied via the USB connector.

How to work with the device

Do-it-yourself intercom key duplicator on Arduino can be used both with and without a COM terminal. To work with the COM terminal, you must first install the appropriate drivers for the Arduino board you are using on your computer.

Any COM port terminal that suits the user best can be used. Before using the terminal, you need to make some of its settings, namely, select a virtual COM port for which the board is defined and the data exchange rate that is recorded in the sketch.

After the device settings are completed, it should be connected to a personal computer and the COM port terminal should be launched. The Arduino module will then automatically reboot. During the download process, the LED indicator will flash several times.

After a few seconds after the download is completed, the device will be ready for operation, the LED indicator will not light in this case, and a message will be displayed in the terminal that the system is ready for use.

The following commands will be available to the user through the terminal:

• the process of loading into the universal identifier buffer;
• switching between read and write modes;
• switching to the mode for manual entry of the ID-identifier;
• transition to the unreadable key recovery mode;
• displaying help on the commands used.

Key reading

To make a duplicator of intercom keys on Arduino, you must first copy the ID-identifier from the original key. In order to read the key, you need to attach it to the contact pad of the device.

The LED in this case will blink rapidly, and the readable ID will be displayed on the terminal. The code read from the original key will be temporarily stored in the buffer until it is reloaded with another identifier.

To store one ID-code, 8 bits are used, which are displayed in a six-digit code.

Write key

In order to write the copied identifier to the writable blank of the intercom key, the terminal should be switched to the recording mode using the appropriate command or using the button on the device. The glow of the LED will indicate that the mode has been changed and the device is ready to write the key ID.

After that, you need to attach the writable key to the pad. At this time, the LED will turn off and after a few seconds it will start flashing at a high frequency, which will indicate the progress of the recording process.

Upon completion of the ID overwrite procedure, the device will automatically enter the read mode. After the device has switched to read mode in the terminal, you can see the newly written ID-identifier.

If the operation was successful, it will correspond to the identifier that was previously read from the original intercom key. If the ID code being written was incorrect or a write error occurred, the terminal will display a corresponding message and the write procedure will be canceled.

Thanks to this, the device protects the intercom key from writing incorrect information to it.

Recovery of an unreadable key

To restore an unreadable intercom key, you need to switch the device to the appropriate mode using a special command in the COM terminal or by holding down the button on the front panel of the device. Next, attach the key to the contact pad.

If it is operational and the ID code can be read from it, then this will happen as in the normal reading mode, after which the corresponding 16-digit identifier will be displayed on the terminal. If the key is not readable, then, accordingly, no procedure will be implemented to the end and the code will not be displayed on the terminal.

In this case, you need to hold the key attached to the pad and press the device button. Thanks to this procedure, the universal identifier will be forced to be written, which was previously registered in the sketch.

After the end of the forced write, the device will automatically enter the read mode. In the future, the universal ID-identifier can be replaced with the original code read from the intercom key.

Other operations

Loading the universal ID-code into the buffer. This procedure can be done by executing the appropriate command in the terminal or by rebooting the device if the universal ID was specified in the sketch.

Copying Arduino intercom keys can be done without the original. To do this, it is enough to know its ID-identifier, which is registered in the scratch and used as a universal code.

The device provides the ability to manually enter an ID-identifier. To do this, you need to set the appropriate command in the terminal, after the execution of which you can enter any ID code in 16-digit form.

Conclusion

Above, we discussed the procedure for how, using a conventional Arduino module, you can independently make copies of intercom keys. Now there will be no problem where to make a new key if the old one is lost or accidentally failed.

In addition, having this device, it will be possible to recover unreadable keys, which can be renewed using the Arduino-based device and the original key ID.

Video: A simple duplicator of intercom keys on the Arduino Nano