Multifunctional code lock. Encyclopedia of radio electronics and electrical engineering

Encyclopedia of radio electronics and electrical engineering / Security devices and object signaling

 Comments on the article

Sometimes, to restrict access to outsiders, it is convenient to have a push-button combination lock. A code lock with a numeric code consisting of 5 characters (out of 11 possible) is easy to perform on just one programmable microcircuit from the RF series. A feature of this circuit (Fig. 2.18) is the use of feedback circuits (diodes VD2 ... VD5) from the output of the microcircuit to its input, which allows, with appropriate programming of the ROM, to obtain a trigger effect (remembering the combination with the correct dialing number).

In the initial state, outputs 1...4 have a log. "1", and on the other outputs the log. "0". The microcircuit is programmed in accordance with table 2.1 (addresses not shown are programmed similarly to the first line of the table).

Fig. 2.18. Wiring diagram (click to enlarge)

The connection of the binary code with the accepted 16-digit designation system is shown in Table 2.2.

The program of the microcircuit (see the line with the address 7FO in Table 2.1) is compiled so that when you sequentially press the buttons connected to inputs 1 ... 4 (pins 8...5), - on the corresponding outputs (pins 9, 11,13) appears log. "0", which is transmitted to the input through the diodes VD2 ... VD5. This fixes the zero state of the corresponding input signal after the button is released.

In order to receive a control signal to turn on the electromagnet, you must press the buttons of the five-digit code in the specified sequence - otherwise you will need to repeat the dialing from the beginning. Pressing any erroneous digit resets all chip outputs to their original state.

Table 2.1

0

1

2

3

4

5

6

7

8

9

A

В

С

D

E

F

000

OF

OF

OF

OF

OF

OF

OF

OF

OF

OF

OF

OF

OF

OF

OF

OF

3FO

OF

OF

OF

OF

OF

OF

OF

OF

OF

OF

OF

OF

OF

OF

OF

8F

400

OF

OF

OF

OF

OF

OF

OF

OF

OF

OF

OF

OF

OF

OF

OF

OF

5FO

OF

41

OF

OF

OF

OF

OF

OF

48

OF

OF

OF

OF

OF

OF

OF

600

OF

OF

OF

OF

OF

OF

OF

OF

OF

OF

OF

OF

OF

OF

OF

OF

6FO

OF

41

OF

OF

OF

OF

OF

OF

48

OF

OF

OF

OF

OF

OF

OF

700

OF

OF

OF

OF

OF

OF

OF

OF

OF

OF

OF

OF

OF

OF

OF

OF

710

OF

OF

OF

OF

OF

OF

OF

OF

OF

OF

OF

OF

OF

OF

OF

OF

720

OF

OF

OF

OF

OF

OF

OF

OF

OF

OF

OF

OF

OF

OF

OF

OF

730

OF

OF

OF

OF

OF

OF

OF

OF

OF

OF

OF

OF

OF

OF

OF

OF

740

OF

OF

OF

OF

OF

OF

OF

OF

OF

OF

OF

OF

OF

OF

OF

OF

750

OF

OF

OF

OF

OF

OF

OF

OF

OF

OF

OF

OF

OF

OF

OF

OF

760

OF

OF

OF

OF

OF

OF

OF

OF

OF

OF

OF

OF

OF

OF

OF

OF

770

10

41

OF

OF

OF

OF

OF

OF

48

OF

OF

OF

OF

OF

OF

OF

780

OF

OF

OF

OF

OF

OF

OF

OF

OF

OF

OF

OF

OF

OF

OF

OF

790

OF

OF

OF

OF

OF

OF

OF

OF

OF

OF

OF

OF

OF

OF

OF

OF

7AO

OF

OF

OF

OF

OF

OF

OF

OF

OF

OF

OF

OF

OF

OF

OF

OF

7BO

20

41

OF

OF

OF

OF

OF

OF

48

OF

OF

OF

OF

OF

OF

OF

7SO

OF

OF

OF

OF

OF

OF

OF

OF

OF

OF

OF

OF

OF

OF

OF

OF

7DO

OF

41

OF

OF

OF

OF

OF

OF

48

OF

OF

OF

OF

OF

OF

OF

7EO

OF

41

OF

OF

OF

OF

OF

OF

48

OF

OF

OF

OF

OF

OF

OF

7FO

00

01

OF

OF

OF

05

OF

07

08

OF

OF

OF

OS

OF

OE

OF

Table 2.2.

0000	0
0001	1
0010	2
0011	3
0100	4
0101	5
0110	6
0111	7
1000	8
1001	9
1010	А
1011	В
1100	С
1101	D
1110	E
1111	F

The indicator of the correct code set is the glow of the HL1 LED. The electromagnet is turned on by the transistor VT2. Pressing the button turns on the call and also resets the previously dialed code (transfers the D1 chip to its original state).

The use of a programmable chip makes it easy to get several additional useful functions. For example, when trying to find a code, an alarm signal (log 1) will appear on the output D16 / 1, which will lead to the operation of relay K1. Contacts K1 1 are included in the security alarm loop circuit. An attempt to select a code is considered if the first three digits are entered correctly, and in the fourth - an error.

Fig. 2.19 ROM emulator

Switch SA1 makes it possible to quickly change the code without rearranging the sequence of connecting buttons to the inputs of the microcircuit. The dialing sequence for the switch position SA1 "CODE 1" is 1-2-3-4-8, and for the position "CODE 2" 4-2-3-1-7. At the same time, buttons with any numbers can be connected to the microcircuit inputs - only the sequence of their pressing relative to the microcircuit pins is important.

The above scheme, despite its simplicity, has great potential for modification for a specific task. For example, the dialed code may consist of two-digit digits - in this case, it will be necessary to correct the programming table without changing the scheme. For this reason, it is better to install the microcircuit on a contact socket.

The topology of the printed circuit board was not developed and the installation is easy to perform on a universal prototyping board. To exclude pickups on wires connecting with buttons, the device is placed near the keypad (30-50 cm). In the presence of interference or when the circuit is operating in conditions of a high level of interference, 1 μF capacitors connected to a common wire can be installed at the inputs of the D0,1 chip.

The circuit is not critical to the types of resistors and capacitors used. Resistors R5 R16 can have a rating of 1 ... 8,2 kOhm. Capacitors C1 ... C2 of type K50-35 for 25 V. D1 chip is replaced by 573RF2 or an imported analogue 2716. Other types of programmable chip can be used, for example, KR556RT6, KR556RT7, but in this case it may be necessary to make changes to the connection diagram. For the convenience of connecting the keypad, an X1 connector of the MPN-14-1 type is used.

The device consumes in standby current no more than 45 mA, which is not essential for stationary power supply. If autonomous power is required, then you can use the 537RU10 or 537RU8 chip (Fig. 2.19). It is used as a ROM emulator for which it is programmed according to the table below with the selected programming voltage of 5 V. And so that the results of the program transfer are not lost when the power is turned off, the microcircuit is transferred to the contact block of the lock circuit with a backup power element (battery or accumulator).

The checksum of the programmed microcircuit is 7ADAH (the KROT/RF programmer was used).

Publication: cxem.net

See other articles Section Security devices and object signaling.

Read and write useful comments on this article.

<< Back

Latest news of science and technology, new electronics:

Artificial leather for touch emulation 15.04.2024

In a modern technology world where distance is becoming increasingly commonplace, maintaining connection and a sense of closeness is important. Recent developments in artificial skin by German scientists from Saarland University represent a new era in virtual interactions. German researchers from Saarland University have developed ultra-thin films that can transmit the sensation of touch over a distance. This cutting-edge technology provides new opportunities for virtual communication, especially for those who find themselves far from their loved ones. The ultra-thin films developed by the researchers, just 50 micrometers thick, can be integrated into textiles and worn like a second skin. These films act as sensors that recognize tactile signals from mom or dad, and as actuators that transmit these movements to the baby. Parents' touch to the fabric activates sensors that react to pressure and deform the ultra-thin film. This ... >>

Petgugu Global cat litter 15.04.2024

Taking care of pets can often be a challenge, especially when it comes to keeping your home clean. A new interesting solution from the Petgugu Global startup has been presented, which will make life easier for cat owners and help them keep their home perfectly clean and tidy. Startup Petgugu Global has unveiled a unique cat toilet that can automatically flush feces, keeping your home clean and fresh. This innovative device is equipped with various smart sensors that monitor your pet's toilet activity and activate to automatically clean after use. The device connects to the sewer system and ensures efficient waste removal without the need for intervention from the owner. Additionally, the toilet has a large flushable storage capacity, making it ideal for multi-cat households. The Petgugu cat litter bowl is designed for use with water-soluble litters and offers a range of additional ... >>

The attractiveness of caring men 14.04.2024

The stereotype that women prefer "bad boys" has long been widespread. However, recent research conducted by British scientists from Monash University offers a new perspective on this issue. They looked at how women responded to men's emotional responsibility and willingness to help others. The study's findings could change our understanding of what makes men attractive to women. A study conducted by scientists from Monash University leads to new findings about men's attractiveness to women. In the experiment, women were shown photographs of men with brief stories about their behavior in various situations, including their reaction to an encounter with a homeless person. Some of the men ignored the homeless man, while others helped him, such as buying him food. A study found that men who showed empathy and kindness were more attractive to women compared to men who showed empathy and kindness. ... >>

Random news from the Archive Swallow surgeon 17.07.2005 In the Italian medical center of St. Anne in the city of Pontedera, a prototype of a surgical robot measuring 2,5 by 1 centimeter has been created. The patient swallows this capsule, the built-in television camera transmits by radio an image of the stomach and intestines. Under the control of a doctor, the robot can perform microsurgical operations. The robot moves on six thin legs, unable to damage the mucous membrane of the digestive tract. Experimental checks are ahead, first on animals.

Other interesting news:

▪ Mussels helped create a super-strong polymer

▪ The right of artificial intelligence to the content it creates

▪ Glasses with massage

▪ Far vision through phone

▪ Smartphone Fly IQ442 Quad

News feed of science and technology, new electronics

Interesting materials of the Free Technical Library:

▪ site section Computer devices. Article selection

▪ article by Friedrich Engels. Famous aphorisms

▪ article Where and when was the lottery invented? Detailed answer

▪ article Video engineer of the department of creative programs. Job description

▪ article Amateur transmitting LW antennas. Encyclopedia of radio electronics and electrical engineering

▪ article Pendulum and the globe. physical experiment

Leave your comment on this article:

All languages ​​of this page

Arabic	Hebrew	Polish
Bengali	Hindi	Portuguese
Chinese	Italian	Spanish
English	Japanese	Turkish
French	Korean	Ukrainian
German	Malay	Vietnamese

Home page | Library | Articles | Website map | Site Reviews

www.diagram.com.ua
2000-2024