Electronic combination lock. The simplest combination lock

The lock is designed to accept a specific four-digit number from the panel. If desired, the number of characters can be increased, but as practice shows, four digits are usually always enough.

The circuit is very simple and, if assembled correctly, does not require adjustment.

Combination lock diagram

As you can see, everything is extremely simple: Buttons SB1... SB4, working to close, are used to dial the set code, and buttons SB5... SB8, working to open, are used to restore the device to its original state, for example, in the event of an erroneous code dialing or its selection.

The lock is activated only when all thyristors VS1...VS4 are opened simultaneously. This can be achieved by successively pressing the buttons SB4, SB3, SB2 and SB1. If you press these buttons in a different sequence, not all thyristors will be open and, therefore, it will not be possible to open the door.

The exception is the case when all four buttons SB1... SB4 are pressed simultaneously. If you press any of the buttons SB5...SB8, the power supply circuit of the electromagnet YA1 is interrupted and the device is returned to its original state. The same will happen when you press all code buttons SB1...SB8. Button SB9 is used to reset the lock after opening the door. The lock is powered from an AC voltage of 220 V through transformer T1 and full-wave rectifier VD2. To power the lock, any power supply with an output voltage of 12≈60 V can be used, depending on the type of electromagnet used.

In this article we will talk about how to assemble a simple electronic combination lock. The scope of application of a combination lock is quite wide; it can be a garage door or a door to a storage room or house. The simplicity of the device allows you to assemble a combination lock, the diagram of which will be given below, even for novice radio amateurs. The parts used are quite common and inexpensive. It will take a little time to assemble the castle.

Each of us keeps some secrets from others. And there is no need to talk about how to reliably hide a valuable item from strangers. I remember when I was a boy, probably like any other boy, I was delirious about treasures and treasures. He took various trinkets, hid them or buried them, then, having drawn a map, solemnly handed it to his friends and they went on a search. Searching, of course, is always more interesting.

But those days are gone, but the need to securely lock the doors remains. For example, for a garage door I made it according to a simple scheme electronic combination lock. The device is powered by a 12 V battery connected to a charger, which ensures constant operation of the combination lock. Now, to open the garage, I dial the required code combination and... bam - the electronic drive is activated and the lock is open.

Well, let's take a look at combination lock diagram, as you can see, it is not particularly difficult; even a novice radio amateur can handle it.

Code lock diagram, or rather a job description. When supply voltage is applied through resistor R1, capacitor C1 is charged, due to which a high-level signal is briefly supplied to the inputs R of elements DD1 and DD2 and sets them to their initial zero state. When the combination lock button SB1 is pressed, a single signal arrives at the C input of the trigger DD1.1, and since the trigger D input is connected to the positive power pole, it (the trigger) goes into a high level state. If you now press the SB2 button, the DD1.2 trigger will also take on a high level state due to the fact that its D input is connected to output 1 of the DD1.1 trigger, and as stated above it is in the single state.

Further, according to the same scheme, if you now press the SB3, SB4 buttons in a row, the DD2.2 trigger will switch to a high level state and transmit it through output 13 to the base of the transistor VT1, passing through the resistor R6. Transistor VT1 will open and itself will open transistor VT2, which in turn will supply current to relay K1. The relay will operate and turn on the electronic actuator of the combination lock.

To disable the mechanism and restore the combination lock to its original state, you will need to briefly press one button from the SB5 - SB9 group. The following will happen, at the R inputs of all flip-flops, see the diagram, voltage will arrive, it is at a high level, and the flip-flops will switch to the zero state. Naturally, the transistors will close as a result, the relay will de-energize and turn off the actuator.

Please note that if, while dialing a code combination, you accidentally or intentionally press any of the buttons SB5 – SB9, the triggers will be reset and the lock will not open. If SB1 – SB4 are not dialed sequentially, the trigger order will be disrupted, and electronic combination lock won't work either.

Details in combination lock diagram those shown in the figure apply, the following replacements in the electronic part are possible. It is permissible to use microcircuits DD1 and DD2 similar to those from the K176 series, but the supply voltage should be no more than 9 V. Any KT315 will be suitable as a transistor VT1, regardless of its letter index. VT2 is completely dependent on relay K1; its collector current must ensure that the relay operates. The type of relay depends on the operating current of the electronic lock actuator. A keyboard with buttons from an old electronic calculator can be adapted to serve as a code combination dialer. Diode VD1 can be replaced with any low-power diode from the KD521 series or an imported analogue.4.25 (8 Votes)

If you want to install a combination lock on your door yourself, it is important to understand its structure. Depending on which model is used, its connection diagram and operating principle may differ. It is important to distinguish between these features, so this issue should be considered in more detail.

Combination locks are either electronic or mechanical

Types of castles

Each entrance door must be equipped with a lock. With a properly selected locking mechanism, home safety requirements will be met. Important criteria when choosing a device are:

degree of burglary resistance;
type of mechanism and lock scheme;
reliability;
privacy level.

Today, the range of products is so huge that you can find a good lock in any price category. Complex mechanisms deserve special attention. Some people do not find a better solution for their home than to make a combination lock at the entrance.

Mechanical. A standard mechanism based on the use of physical force to activate the locking bolts.
Electronic and magnetic. Powered by mains or battery. Operation requires a radio signal or a magnetic key.
Combined. They can work as electromagnetic models, and in the event of a lack of power, they switch to the mode of a regular lock with a key.
Mortise. They are installed on the door leaf from the outside of the door and have a visible end plate.
Nested. They are mounted at the door manufacturing stage directly inside the door leaf.

Types of door combination locks depending on the principle of operation

Based on the type of locking device, combination locks are classified in the same way as regular locks.

Features of mechanical devices

Previously, mechanical combination locks were used almost everywhere. They were actively installed on the entrance door of apartment buildings. Also, the scope of their application extended to the entrance area to utility and industrial premises. The principle of operation of the mechanics is based on the introduction of a code combination of several numbers, which set the crossbars in motion and unlocked the door when the necessary buttons were held.

The design of a modern mechanical combination lock is somewhat complicated, since older models turned out to be not very reliable due to the ease of selecting a combination based on pressed-in operating buttons. Today, their scheme is more often based on the sequential introduction of numbers, but the mechanism itself has remained approximately the same.

The advantage of mechanical models is that their connection diagram is extremely simple. They do not require connection to batteries, and therefore it is enough just to embed the product into the canvas and attach the mating part to the box.

Reprogramming a mechanical lock with your own hands also does not pose any particular difficulties. To do this, you need to do the following: disassemble the case and change the access code to a new combination, connecting the buttons with the crossbars.

The advantage of a mechanical combination lock is its ease of connection.

Electromagnetic models

Of course, purchasing a mechanical lock is a good budget option, however, electromagnetic models are more reliable and efficient; they are installed on the front door in apartments, private houses, offices, etc. Such locks have the main difference - they operate on electricity. Energy consumption is small, and therefore you don’t have to worry about extra kilowatts on the meter. In addition, you can use rechargeable batteries so as not to lay a cable to the nearest network.

Electronic. The basic model is an electronic lock that you can program yourself. It can work on different principles. In some products, the combination reception scheme is based on its manual input on the keyboard. Other locks operate by receiving a radio signal, which sends a special key programmed to store the required code. In order for the system to work, it is necessary to provide the lock with power. For convenience, some models are equipped with a display. Buttons can be either regular push buttons or touch buttons, as in more expensive and modern products.
Magnetic. They also require power from batteries or mains, but the principle of operation of the magnetic lock is based on a slightly different approach. The main element is the magnetic key, which is the carrier of the code. It can be in the form of a tablet, key fob or card. In order to open the door using a magnetic lock, you need to attach the key to the receiving plate. After processing the signal, the mechanism is activated and the door opens. The device of a magnetic door lock is clearly demonstrated by the intercom.

Electromagnetic door locks are considered the most reliable for security

A magnetic and electromagnetic lock are essentially the same device. The main condition is the use of a magnetized key to enter the code and unlock the mechanism. In exclusively electronic models, the circuit is based on the delivery of an electrical impulse.

Installation Rules

The diagram for installing a combination lock on a door with your own hands for mechanical models is quite simple. The idea is to attach a digital panel with a secret mechanism to the canvas, and insert a counter plate into the canvas. The simplest models contain crossbars that can be moved manually from the inside using a special lever or button.

Installing a mechanical combination lock is quite simple and does not require special skills

But how to install an electromagnetic lock on a door with your own hands? Here you need to have basic skills in working with power-powered devices. Also, for a specific model of a magnetic or electronic product, instructions must be attached with a step-by-step description of the technology for connecting the elements of the unit. The ideal option is when the connection diagram is displayed not only in text form, but also schematically.

The technology for installing an electric lock with your own hands is as follows:

Determine the position of the lock panel on the door.
Mark the exact location where the panel will be inserted.
Drill holes in the canvas according to the marks.
Cut a hole of appropriate size to accommodate the lock block and locking mechanism.
Next you need to connect the code panel to the lock drive.
For an electric lock, you need to make access to the power supply.
Then you need to program the lock by setting an access code on the device and check that the mechanism is working correctly.

Installing a combination electric lock on your front door will allow you to increase reliability and security. If you do everything correctly, you will not regret the decision you made and will prevent damage to the device during long-term use.

The circuit of a simple electronic combination lock. The circuit is not complicated, you only need to flash the PIC microcontroller. For this circuit you need PIC 12F675 (629) - it won’t work.

The diagram itself is very simple and contains a minimum of details.
Lock diagram:

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Keyboard layout:

The principle of operation is very simple: all buttons are connected through a chain of series-connected resistors. And each button has its own resistance (if button No. 1-1k, then button No. 2-2k, and so on). All these values are written into the microcontroller when programmed, after which it responds only to them.

Programming the code is very simple: press the CODE button and hold until the LED lights up, then enter the code on the keyboard. All the new code is programmed (for those who don’t understand, watch the video of the operation at the bottom of the article)

The actuator (M) can be anything, in my case it is a low-power electric motor that will rotate the gearbox: so I connected it to the same power source as the circuit itself. If you have a powerful actuator: then it should be connect from an additional power source.

I found only a matrix keyboard, here it is in the photo

The problem was that. its connection looks like this:

I had to redo it, cut the tracks and soldered in the resistors as in the diagram, this is what happened:

I did not connect one row of buttons (these are the letters A, B, C, D)
Only the letter (D) is connected as a power button (that is, the circuit only works if you hold down the button (D)) This reduces the probability of selecting the code to zero.
And the combination lock itself does not consume any current in standby mode.

I want to put this lock in the locker at work, which I often break into, and I don’t want to take out a bunch of keys every time. Since the standard lock will remain in place, I made a power supply from batteries (so that there would be no wires to the box), well, once every few months you can open the door with the keys and change the batteries.

First assembly of the circuit on the circuit board (to check its functionality)

Everything worked great. Next, I selected a suitable case, etched the board and connected everything. Due to the small number of parts, the board turned out to be quite compact and fit into a small case.

Practical combination locks are in greatest demand today. After the first steel door was invented, installed at the entrance of the house, many began to think about how to protect their home from uninvited guests. Locks are structures for protecting premises that have been manufactured for a very long time. There are various types, configurations, operating features and similar differences, but the essence of the mechanism remains completely unchanged, since the design is designed to block access to the room. Despite the fact that there are many modern technologies, installations such as a combination mechanical lock, the production of which began in the last century, continue to be popular. Initially, they were installed on safes, and over time they were also used in installing doors in ordinary apartments, garages, entrances and private houses.

Combination lock device and DIY installation

The design of combination locks is that they do not have a keyhole, due to which they become more reliable, wear-resistant and durable. The likelihood of hacking is significantly reduced. By installing a specific coding of the cylinders and rollers that make up the lock, you can customize the lock yourself, and installation can be carried out on doors made of various materials, for example: metal, plastic and wood. It is advisable that the door thickness be at least 3 cm, which will also complicate the burglary process for intruders.

You can select and install a combination lock yourself if you carefully read the instructions

The diagram for installing a lock on the front door with your own hands is very simple, since for this you need:

Select a door locking mechanism relative to the width and thickness of the structure;
Make a marking of the future location of the product;
Use a drill to drill holes in the door to install the lock body;
Install the code panel;
Assemble the locking mechanism;
Carry out installation and fixation of prefabricated parts of the mechanism;

Finally, you need to set up the code combination and check the functionality of the product.

How to make a combination lock: choosing a variety

To install a push-button door lock, you will first need to select its type. They are: overhead and mortise. To install a surface-type lock, simply install it on the surface of the door, and the bar with the bolt located in it on the jamb of the door frame. Installation will not require more than 15 minutes. Installing a mortise combination lock can cause a lot of trouble and this is where special attention and a competent approach are required.

Making a combination lock is not difficult, the main thing is to approach this process competently

As a rule, each magnetic door lock has instructions from the manufacturer, which must be followed as clearly as possible:

A lock template is created, which is done by hand. Some manufacturers include it in the kit, and this greatly simplifies the installation process. Using chalk or a pencil, you need to apply markings to the door leaf. Thus, the location of the structure will be marked on the door on both sides.
To make a niche on the door leaf for installing a lock, you can use a chisel or a special attachment for a drill.
Next, holes are drilled to install the bolts.
Where the crossbar of the lock structure is located, you need to make a recess, and the dimensions must completely correspond to the front plate.
After completing such work, the combination lock is placed in its rightful place and securely bolted.
The face plate is being installed.
It is necessary to make markings on the door jamb for mounting the locking strip, into which the bolt will be placed. To carry out this process, it is enough to lubricate one of the crossbars with chalk, due to which a mark will be made on the jamb.
A recess is made in the jamb for the plank, and you also need to mark the holes to install it. The installation process fully corresponds to the installation of the front strip.
Finally, you need to secure the counter or locking part of the lock.

Judging by the steps described above, we can conclude that installing a mortise combination lock is similar to installing other types of locks in the same way.

Combination lock repair

To make repairs on a structure such as a digital combination lock, it will not require too much effort, since the main repair work consists of recoding the structure. In addition, preventive recoding is periodically required to increase the safety of the product.

In order to repair the combination lock, it will need to be properly disassembled.

To change the code on the lock, partial disassembly of the structure is required to gain access to the buttons from the inside, for which you need to unscrew the cover with the buttons.

Next, you need to pay attention to the plates located inside, when pressed, the locking mechanism is activated, and each of them has a specially made cut. Visually separate the working and unused plates. To replace the code, turn the required plates in the opposite direction or, in other words, make other buttons active.

DIY invisibility lock

An electronic invisible lock is an additional device that can be used to increase the security of an apartment, house or any other premises. From the outside, the electric lock is completely invisible, but inside it is a reliable installation that can prevent intruders from entering. To make such an electromagnetic lock with your own hands, you can use the most ordinary car door actuator from the central locking, and it is controlled or, in other words, blocked by the most ordinary alarm system.

An invisible combination lock is practical and convenient.

The essence of such an invisible thing is to block one keyhole bolt in the position when it is pushed forward:

Due to the fact that the car anti-theft alarm device has enough wires, and a long type, it is possible to carry out competent and easy installation.
It is necessary to select a place for subsequent installation of the actuator, since the pin that will be extended must fit exactly into the bolt when it is extended.
Next, you need to make precise markings on the top strip of the door frame, and it is drilled. Then a mark will be made on the crossbar, along which an additional through hole will be drilled.
When the bolt is drilled into the hole, a countersink is made so that the actuator pin fits there as accurately as possible.
Using the strip that comes with the kit, you need to secure the actuator to the door frame.
Next, a guide from 1 pin and a limit switch are installed on the door frame so that it is triggered to open the door.
Installation of the alarm unit, as well as all related elements located in a decorative metal box, is required. The box is installed on the wall surface next to the door on the inside of the room.
The box closes tightly.
An LED indicator or, in other words, an alarm system is connected to the doorbell button.
The structure is ready for use.

If a power connection is required, this can be done using a stabilized unit, which has an output voltage of 12 V and a current of at least 1 A. To increase the autonomy of the device relative to the network voltage, you can use a battery from a car to power such a lock, which will be located in pantry or on the balcony.

Types of combination mechanical locks (video)

It is not difficult to make such a structure, but you need to follow the recommendations and sequence of actions. It is very important that all wires connected to the battery and the alarm itself are in good working order and carefully insulated, which will prevent the formation of sparks and interruptions in the operation of the system.

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