Code lock with display on avr microcontroller. Microcontroller electronic lock. About my build

Schematic diagram of a two-level security system, which is built using AVR microcontrollers of the ATMega series. 1st level of security - combination lock. 2nd level of security - security device. Two functional boards included in the system are based on ATmega 8535 microcontrollers.

Structural scheme

Microcontrollers (AVR, MCS-51, etc. families) with their architecture, software and hardware resources, like digital cubes, are ideal for the development of various security devices, alarms, combination locks, etc.

Rice. 1. Structural scheme security systems.

The system (Fig. 1) has two main components: combination lock A2, and security device A1. Security device A1 has 24 independent input lines to which limit switches S1...S24 are connected. These switches control the status of windows 01...05, doors D1, hatches L1, L2.

The number of the above control objects may vary and is tied to each specific premises or protected perimeter.

The number of security devices A1 and combination locks A2 used is also not limited in any way and is determined by the security conditions, the degree of protection, the characteristics of buildings, premises, etc. It is clear that limit switches S1...S24 can control those doors, hatches access to which is limited by code lock (or combination locks) A2. The schematic diagram of the combination lock is shown in Fig. 2.

Schematic diagram

Let's consider the operation of the security device. External (remote) elements in relation to the device are 24 limit switches (S1...S24), which allow you to control the state of 24 objects (for example, a door). One limit switch controls the status of one door. If the door is closed, the limit switch is open.

The user (operator, dispatcher) can visually check the status of the door based on the status of the indicator.

If the door is open, the limit switch is closed. The indicator flashes periodically. If the door is closed, the limit switch is open. The indicator is not lit (extinguished). Let limit switch S1 be installed in door No. 1. Let limit switch S2 be installed in door No. 2, etc.

If door No. 1 is open, the HL2 indicator flashes periodically (if door No. 1 is closed, the HL2 indicator is off). If door No. 2 is open, then the HL3 indicator blinks periodically (if door No. 1 is closed, the HL3 indicator is off), etc.

The author will not dwell on any specific design of the limit switch installation, as well as the design of the device itself. The monitoring and control interface of the device includes: toggle switches SA1, SA2, indicators HL1...HL25. Structurally, it is advisable to place all the above elements on a separate control panel.

Rice. 2. Schematic diagram of a combination lock for a security system.

The device control interface elements have the following purposes:

• SA1 (SECURITY) - alarm toggle switch. When this toggle switch is set to the “ON” position, the device is armed. The device is armed after ~ 10 seconds. from the moment the toggle switch SA1 is installed in the “ON” position from the “OFF” position. After arming, the alarm is triggered ~ 10 seconds from the moment any limit switch S1...SA24 is closed.
• SA2 - mute switch. This toggle switch operates only in door status monitoring mode. Toggle switch SA1 must be set to the "OFF" position. When you set the toggle switch SA2 to the "ON" position, when you open any door, the piezoelectric emitter BA1 will immediately output sound signal, lasting ~ 2 sec. If this toggle switch is in the “OFF” position, then when any door is opened, only the corresponding indicator will flash periodically, the piezoelectric emitter BA1 will be turned off.
• HL1 - security mode activation indicator. If the device is in the "security" mode, this indicator is on; if in the "door status control" mode, this indicator is off.

The alarm is triggered - this means: relay K1 is constantly on. Pins 5 and 6, as well as 2 and 3 of this relay are closed. Piezoelectric emitter BA1 - turns on and off with a period of ~ 1 second. To turn off the alarm, toggle switch SA1 must be set to the “OFF” position.

Let's look at the main functional units schematic diagram devices. The basis of the device is the DD1 microcontroller, the operating frequency of which is set by a generator with an external resonator ZQ1 at 10 MHz.

Rice. 3. Schematic diagram of a security device on a microcontroller.

Connected to the PD port of microcontroller DD1 are switches SA1, SA2 with a piezoelectric emitter BA1, indicator HL1, and a key on transistors VT1, VT2 for controlling relay K1. Limit switches S1...S24 and indicators HL2...HL25 are connected to ports PB, RA, PC of microcontroller DD1.

Power to these indicators is supplied through a switch on the VT3 transistor, which is controlled from pin 21 of the DD1 microcontroller. Resistors R10...R17, R20...R27, R28...R35 are current limiting for indicators HL2...HL25. Resistor R8 is current limiting for the HL1 indicator.

Relay K1 is controlled accordingly from pin 14 of microcontroller DD1. The supply voltage +12 V and +5V is supplied to the device from connector XI. Capacitor C5 filters ripples in the +5 V power circuit. Blocking capacitors C4 are located along the power supply circuit of the microcontroller DD1.

In the operating algorithm of the device, two operating modes can be distinguished: door status monitoring mode and security mode. Let's consider the algorithm of operation of the device in the door status monitoring mode. Keep all doors of the protected facility closed. Toggle switch SA1 is in the "OFF" position.

Toggle switch SA2 is in the "ON" position. After power is supplied to the device, during initialization, logs are written to all bits of the PB, RA, PC ports of the DD1 microcontroller. 1. The switches on transistors VT1...VT2 are closed, the indicator -HL1 is off.

Indicators HL2...HL25 are extinguished. Limit switches S1...S24 are open. A periodic signal (square wave) with a period of about 1 s is generated from pin 21 of microcontroller DD1. If you open door No. 1, limit switch S5 will turn on.

The HL2 indicator will flash periodically with a period of ~ 1 second. The piezoelectric emitter BA1 will produce a sound signal lasting ~ 3 seconds.

If you open door No. 2, limit switch S6 turns on. The HL2 indicator will flash periodically with a period of ~ 1 second. The piezoelectric emitter BA1 will produce a sound signal lasting ~ 2 seconds, etc. If you set the toggle switch SA2 in the “ON” position, then when any limit switch is closed (when any door is opened), the corresponding indicator will only blink.

Let's consider the operation of the device in security mode. Keep all doors of the protected facility closed. Toggle switch SA1 is set to "OFF".

The device goes into security mode ~10 seconds after setting the SA1 toggle switch to the “ON” position. During this time, it is necessary to close all doors and leave the protected facility. It is clear if the perimeter of the protected object is large enough and in 10 seconds. It is impossible to close all doors, then all doors must be closed before arming the object.

If in the security mode any of the limit switches S1...S24 is turned on (any door is open), then a logic level signal of 0 will be present at the corresponding output of the ports PB, PA, PC of the microcontroller DD1. then after ~ 10 sec. The sound alarm will turn on (piezoelectric emitter BA1). In this case, at pin 14, microcontroller DD1 will set the level to log.0 (relay K1 will turn on).

If a “friend” penetrates the protected object, then he needs to set the SA1 toggle switch to the “OFF” position within ~ 10 seconds, otherwise the alarm will go off. It is clear that access to switch SA1 should be limited.

If a “stranger” enters a protected object (through an open door), then he needs ~10 seconds. Find the SA1 switch and set it to the "OFF" position. The alarm will also turn on if any of the limit switches S1...S24 turns on for a short time (for example, close and immediately close the door). Relay contacts K1 can be used to close control circuits or power various actuators, for example, for a door locking mechanism or to turn on a siren (howler).

The developed program in assembler takes up only about 0.4 KB of program memory of the DD1 microcontroller. Unused hardware (lines PD6, PD7) and software (about 7.6 KB) resources of the DD1 microcontroller can be used for additional options.

For example, you can install a couple of buttons and add the function of arming and disarming the device via an access code or control some other actuators. Having understood the program, you can replace the device parameters set by software:

• blinking period of the HL1 indicator;
• duration of the sound signal from the piezoelectric emitter BA1 in the door status monitoring mode;
• the time for arming the device, as well as the delay time for turning on the alarm.

The device uses resistors S2-ZZN-0.125; any others with the same dissipation power and an error of 5% will do. Capacitor C5 type K50-35. Capacitor C1...C4 type K10-17a. Capacitor C4 is installed between the +5V circuit and the common conductor of the microcontroller DD1. Toggle switches SA1...SA2 type MTD1.

Relay K1, type RES48B, version RS4.590.202-01. These relays, with an operating voltage of 12 V (or with some other operating voltage), can be selected for each specific case, taking into account the switched current and voltage of the connected actuator.

You can choose absolutely any limit switches for each specific case. This could be a button of the PKN124 type, or, for example, a waterproof track switch of the VPK2111 type. Piezoelectric emitter BA1-НРМ14АХ.

Transistor VT1 - KT829A. Transistors VT2, VT3 -KT3107E. Indicator HL1 - AL307AM, red. The HL1 indicator can be replaced with any other one, preferably with a maximum forward current of up to 20 mA.

Let's consider the operation of a combination lock (hereinafter referred to as the lock) according to Figure 3. The algorithm of its operation is quite simple: in write mode, a code is entered into the EEPROM of the microcontroller, which consists of 4 decimal digits and is typed on a 7-button keyboard. Next, to check, the recorded code is read in read mode. In operating mode, the lock waits for a code to be entered.

The microcontroller writes the entered code into RAM and compares it byte by byte with the code written in EEPROM. If the codes match, the microcontroller sends a signal for five seconds to turn on the lock opening mechanism.

In addition, the procedure for dialing a code can be open (the dialed code is displayed on the display, each pressed button is assigned a number on the display) and closed (when dialing a code, identical, predetermined symbols are displayed on the display, each pressed button is assigned a specific symbol, for example).

There is a separate switch in the lock for this purpose. To activate the 4-digit code displayed on the display in recording mode and in operating mode, just press any button on the keyboard.

The device interface includes a scale, character-synthesizing indicator HG1, an indication unit (display) of digital seven-segment indicators HG2...HG4, switch SA1, and a keyboard (buttons S1...S8).

Buttons S1...S7 are designated by numbers from "1" to "7". These buttons set the input code. Button S8 (P) sets, in a cycle, one of three operating modes: “mode No. 1”, “mode No. 2”, “mode No. 3”. After mode No. 3, mode No. 1 is activated.

Element No. 1 of the HG1 indicator is turned on when working in mode No. 1", element No. 2 of the HG1 indicator is turned on when working in mode No. 2, and element No. 3 is turned on, respectively, when working in mode No. 3. On a 5-digit display (dual digital indicators indicator HG2, HG3 displays the entered code.Indicator HG4 displays the symbols “3” (when the lock is closed) and “0” (when the lock is open).

Switch SA1 sets the code display mode on the device display. If this switch is in position "1", then the code specified from the keyboard is displayed on the device display. If in position “2” (hidden mode), then when typing a code, the symbols are displayed in each digit on the device display

In mode No. 1 (operating mode), the lock is ready to enter a code to open the lock (if, of course, the code was previously written into the EEPROM). Before dialing the code, code 0000 is displayed on the display. Element No. 1 of the HG1 indicator is turned on (the other elements of the HG1 indicator are turned off).

The HG4 indicator displays the symbol "3" (closed). Using buttons S1...S7, a 4-digit code is dialed. The dialed code is indicated on the display. After pressing any of the S1...S7 buttons, the microcontroller writes the received 4-bit code into RAM and begins checking the code written in RAM and the code written in EEPROM. The codes are compared byte by byte.

If the comparison was successful, the microcontroller sends a signal to the lock opening actuator. Element No. 4 of the HG1 indicator turns on for five seconds, the HG4 indicator displays the symbol “O” (open) and the log is set. 0 on pin 21.

After five seconds, element No. 4 of the HG1 indicator turns off and a log is set at pin 21. 1. The display shows code 0000 again. The HG4 indicator again displays the symbol “3” (closed).

In mode No. 2 (recording mode), recording is carried out secret code in EEPROM. The display shows code 0000. Element No. 2 of the HG1 indicator is turned on. The HG4 indicator displays the symbol "3" (closed). Use the SI...S7 buttons to dial the code. The dialed code is indicated on the display.

The microcontroller writes the 4-digit code displayed on the display to the EEPROM after pressing any of the buttons 51...57. After writing the code, the display shows code 0000 again.

In mode No. 3 (recorded code verification mode), the recorded secret code in the EEPROM is checked. Element No. 3 of the HG1 indicator is turned on. The HG4 indicator displays the symbol "3" (closed). The recorded code in EEPROM is indicated on the display.

It is clear that access to the S8 button and SA1 switch should be limited. Structurally, this is not so difficult to do.

Let's consider the main functional components of the device (Fig. 3). The basis of the device is the DD1 microcontroller, the operating frequency of which is set by a generator with an external resonator ZQ1 at 11.0592 MHz. The PD port of microcontroller DD1 controls the dynamic indication.

Dynamic indication is assembled on transistors VT1...VT5, dual, digital, seven-segment indicators HG2, HG3 and single digital indicator HG4. Resistors R7...R14 are current limiting for indicator segments HG2...HG4. The codes for turning on the above indicators when the dynamic indication is functioning are sent to the PC port of the DD1 microcontroller.

For the keyboard to function, pin 19 (PD5) of the DD1 microcontroller is used. The elements of the HG1 scale indicator are connected to the pins of the PB port of the DD1 microcontroller. Resistors R2...R5 are current limiting for indicator elements HG1.

Immediately after power is applied, a system hardware reset signal for microcontroller DD1 is generated at pin 9 of the DD1 microcontroller through an RC circuit (resistor R1, capacitor C3). The display shows code 0000. Element No. 1 of the HG1 indicator is turned on. The HG4 indicator displays the symbol "3" (closed).

The +5V supply voltage is supplied to the device from connector XI. Capacitor C5 filters ripples in the +5 V power circuit. Blocking capacitor C4 is located along the DD1 power supply circuit.

Very briefly about the program. The program uses two interrupts: Reset and the TO timer interrupt, the handler of which begins with the TIM0 label. When you switch to the Reset label, the stack, timer, ports, as well as flags and variables used in the program are initialized.

The TO timer generates overflow interrupts (TOIE0 bit is set in the TIMSK register). The timer clock pre-division factor is set to 64 (the number 3 is written in the TCCR0 register).

In the main program, elements of the HG1 indicator are included. The included elements of this indicator, as mentioned above, determine the current operating mode of the lock. In the TO timer interrupt handler, the following is carried out: the procedure for polling buttons S1...S8, the functioning of dynamic indication, writing a secret code to EEPROM, reading a secret code from EEPROM, converting a binary number into a code for displaying information on seven-segment device indicators, as well as a time interval duration of five seconds required to turn on the solenoid actuator.

A display buffer for dynamic display is organized in the microcontroller RAM from address $61 to address $70. Below is the detailed distribution of address space in the microcontroller RAM.

• $60 is the start address of the microcontroller RAM.
• $61...$64 - addresses where the specified code for opening the lock and the symbol “3” are stored. These addresses are displayed in mode No. 1 (buffer No. 1).
• $66...$69 - addresses where the code read from EEPROM and the symbol “3” are stored. These addresses are displayed in mode No. 3 (buffer No. 2).
• $6С...$70 - addresses where hidden typing symbols and the symbol "3" are stored. These addresses are displayed in mode No. 1 (buffer No. 3).

The flags involved in the program are located in registers R19 (flo) and R25 (flo1).

The developed assembler program occupies about 1.2 KB of program memory. Having understood the program, with minor modifications to the circuit diagram, using the free hardware and software resources of the DD1 microcontroller, you can, for example, increase the number of digits in the display and the number of buttons or add a sound alarm.

Resistors of the C2-ZZN type are used; any others with the same dissipation power and an error of 5% are suitable. Capacitors C1...C4, type - K10-17a, C5 - K50-35a. connector XI type WF-4. Capacitor C4 is installed between the +5V circuit and the common conductor of the microcontroller DD2. To test the prototype, an SA1 switch of the VDMZ-8 type was used.

For installation in a block housing, you can use, for example, a switch of the MTZ type. The display has a highlighted digit indicating the symbols “3” and “O” (indicator HG4) against the background of the other digits of the interface. Therefore, for this category, a seven-segment green HDSP-F501 indicator and green DA56-11GWA indicators HG2, HG3 were selected.

The lock and security device do not require any configuration or adjustment. When installed correctly, they begin to work immediately.

Source code and firmware of programs - Download (8 KB).

Shishkin S.V. RK-07-16.

Literature:

1. A. V. Belov We create devices on microcontrollers.
2. S. V. Shishkin. Combination lock based on a microcontroller. R-10-2011.

I work as an electrician in the Far North. In winter, we always had a problem: the lock at the entrance to the electrical shop freezes. And then the magazine “Radio” No. 5 for 2008 caught my eye. An article by E. Pereverzev “Digital Code Lock” was published there.

I decided and did it. Redrawn a signet from a magazine. I soldered the circuit.
I uploaded the firmware and the circuit worked immediately, although this is my first circuit on a microcontroller.

About my build

Version of the signet from the article by E. Pereverzev

The circuit itself, the “Opening” and “Closing” buttons, were placed in the power supply box under the vacuum switch control unit.

The power supply was used from an old scanner.
The solenoid was used from an old electrical laboratory, one drawback is that the solenoid consumes 1.5 A.

I took the keyboard from an old phone.

--
Thank you for your attention!
Igor Kotov, editor-in-chief of Datagor magazine

Original article from Radio:
▼ 🕗 12/20/11 ⚖️ 512.66 Kb ⇣ 111 Hello, reader! My name is Igor, I'm 45, I'm a Siberian and an avid amateur electronics engineer. I came up with, created and have been maintaining this wonderful site since 2006.
For more than 10 years, our magazine has existed only at my expense.

Good! The freebie is over. If you want files and useful articles, help me!

It was in the evening when an persistent, oversized woman appeared on the threshold of the office, offering to buy dishes from a famous brand. The very next day I received from my boss (aka) the task of protecting his creative nature from attacks sales representatives. This is how the idea of ​​creating a project codenamed Hungry_Wall came about. Of course, now there are many services involved in controlling access to premises. But it’s much more interesting to make an electronic lock with your own hands, especially for me, a novice programmer and electronics engineer.

As they say, the main thing is to correctly draw up the technical specifications, i.e. what we want to get as a result.

1. Create a key recognition system.
2. Compare the key with the database, and if the code of the presented key matches one of those recorded in the database, open the lock.
3. Take readings from the magnetic sensor to identify the door's condition, and if the door is open, close the lock.
4. Use a timer after which the lock closes if we change our minds about entering/exiting. This is designed to prevent “enemies” from getting into the secret lair by taking advantage of our change of mood.
5. Ensure the door opens using a button located inside the room.
6. Recording a new key in the database after presenting the master key and, naturally, recording the master himself.
7. Removing a key from the database (feature).
8. Display system for greater attractiveness.

Half the work is done, all that remains is to implement the plan in hardware and software. To do this you need:

1. Electric lock
2. Proxy (em-Marin) card reader "CP-Z" from IronLogic
   
3. Keys or cards for recording in the database
4. Button
5. Power supply 12 V
6. Body (so that everything is neat and beautiful)
7. Electronics – microcontroller ATmega 8, “cribX28”, stabilizer KR1158EN5V, transistor IRLU 024 N, 6 KLEM 2 connectors, 1 WF 3 connector (COM-port), capacitor, LEDs and resistors to taste.

The board layout is shown in Diagram 1.

The board's internals are shown in Figure 1.

To solve the assigned problems, all used devices are divided into logical blocks presented in Diagram 2.

The lock block includes an electric lock itself, a timer TimeOpen, which allows you to set the maximum time the lock is open, and a magnetic sensor that indicates the opening and closing of the door. The input of the lock block is the command to open the lock (Open), coming from the oarlock and button blocks. The oarlock block consists of a reading device, a database, and a TimeMaster timer, which sets the maximum time for submitting a new key for writing to the database. Entrance to the block is carried out by presenting a key or a master. The button block consists of a button that can take 2 states (pressed/not pressed).

To read contactless cards, the “CP-Z Proxy Card Reader (em-Marin)” from IronLogic is used; its peculiarity is that it emulates an iButton (1-wire) if you bring a proxy card to it.. this allows you to simplify programming the lock. However, it should Please note that this version of the reader has its own underwater rake.

The operating principle is extremely simple. When you present the key, its code is read and compared with the base. If the key is found in the database, the lock receives the Open command. Here it is necessary to take into account the peculiarity of the lock: opening must be done with clicks (open-close-open). This provides protection against jamming of the lock. When the master is presented, the logic of the program changes. Its presence does not in any way affect the “mood” of the castle. He is seen as a kind of Turkish sultan, ready to register (write to EEPROM) his next wife (key). Those. when the key is presented (if it has not been previously recorded), its code is written to the EEPROM. Here it is necessary to take into account that the memory of the mikruha is non-rubber, and, for example, for ATmega 8 it is 512 bytes, which allows you to record a maximum of 255 keys (if you use 2 bytes to store 1 key, as in our case). The very first key presented is recorded as the master. Pressing the button also sends the Open command to the lock. The display system makes our project more colorful and informative. If the red diode is on, the passage is blocked; if it is green, you can go! When the master is brought up, both LEDs light up.

It is important to note that the lock opens when a logical unit (i.e. voltage) is applied to it, and is in a closed state if voltage is not applied. This allows you to block the passage if you forget to pay utilities and your electricity is turned off.

The appearance of the entire device is shown in Figure 2. Everything is quite neat and beautiful.

You can download the sources

The code call circuit is implemented on the ATtiny2313 microcontroller. The combination lock circuit consists of an AVR microcontroller and a transistor key that controls the relay.

To record the code, close the “sw” toggle switch, thereby switching the lock to code recording mode. Enter the dimension of the code combination using buttons from 1 to 7 (buttons 8, 9 and 0 are not used in the dimension set), enter any code combination equal to the code dimension.

The email will work. the lock magnet, opening it, thereby signaling that the code combination has been recorded in the “EEPROM” memory.
Work mode. We turn off the “sw” toggle switch and put the lock into the mode of checking the recorded code combination. We repeat the sequence for the recording mode, enter the size, enter the recorded code.

Schematic diagram of a combination lock on the AVR microcontroller:

The code dialing always starts with book. 1 _ 7 (dimension). When dialing a code combination, the code can be entered not only one digit at a time, but also, for example, by pressing the button. 7, without releasing, press the button. 8 then press the button. 6 and release one button in any sequence, as a result a five-digit code combination will be dialed.

If, after entering the correct combination, the lock does not open, you need to press the button several times. 8 - 9 or 0, maximum 7 times, or press these buttons at the same time twice and repeat the code. This may indirectly mean that an attempt was made to open the lock.

When flashing the microcontroller firmware, the fuse bits must be set as follows:

The assembled combination lock looks like this:

This project will excellent option for beginners to repeat, it uses a 1602 LCD display, a 4x4 keyboard of buttons and of course the controller itself. In addition, a relay, a button and power connectors, PLS pins, a couple of transistors and little things were used. By the way, the brightness of the display in the project will be adjusted using the PWM method.

This device can be used to protect almost any object, the user must enter the correct password to gain access. The board has already been designed in a convenient way, and all that remains is to make a beautiful case for it. The password is entered using the 4x4 matrix built into the keyboard. The main LCD display module is used to display messages to the user and current information. As soon as the correct password is entered, the relay will operate. This will also be indicated by an LED installed next to the relay. To turn off the relay, you need to press the corresponding button on the keyboard.

After entering the four-digit password, you must press the "OK" button (S8). At any time, you can press the Cancel button (S12) to clear the code (for example, when entering any incorrect numbers).
The lock code can be easily changed by entering a special password “0000”, as soon as you enter this password, the device will switch to password change mode. Here you need to enter the old password to get permission and then enter the new password, it's very simple.

The LCD backlight turns off automatically after the system has been in standby mode for a few seconds. The backlight dims very smoothly, just like in mobile phones. The display can be replaced with any similar one, with a similar controller or even a different resolution, the main thing I advise you to pay attention to is the pinout; in some models the display pinout may differ. The program for the controller is written in C++, the source code, as well as the firmware for the controller, are included. The microcontroller can be used with any index; the letter L means reduced power consumption.

File printed circuit board for the manufacture of is located below in the archive, the printed circuit board can be noticeably reduced if you use smaller buttons, or if you move the keyboard to a separate board. The number keys can be taken from an old computer or laptop keyboard.

Fuses:
HIGH=D9
LOW=E1

You can download the PCB file, source and firmware below

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