Node of a light imitator of a security alarm
Recently, it often becomes necessary to simulate the presence and active state of electronic signaling devices. First of all, this is done for prevention purposes. And secondly, so that the potential anti-social element of society does not encroach on the property belonging to the rightful owner. Unfortunately, the psychology of the antisocial element is such that it is almost impossible to convince or force him to change his criminal lifestyle, especially if he is over 18 years old, especially if he has experience of successful thefts. Law-abiding citizens can only jealously guard their property.
For this, a simple device containing a minimum of parts is proposed. This is a light simulator of an alarm activation - an LED that flashes at regular intervals, indicating that the alarm is on. The device works in the same way as a car light alarm in the form of a red LED. Such an LED is installed under the windshield of the car from the side of the passenger compartment and flashes when the "security" mode is turned on. A similar light effect is observed in various blocks of apartment alarms, such as "Comet", "Center", "Spectrum", etc. In Fig. 4.6 presents a simple electrical simulator of a security alarm, which almost everyone can repeat.
Oxide Preferably with a minimum leakage current, for example from the K52-x series.
fixed resistors. Any of the MLT series.
The turn-on delay time of the transistor can be increased by proportionally increasing the resistor R\ and the capacitance of the oxide capacitor C\. However, you should not increase the capacity of the indicated elements to infinity, since 20% of the elements indicated on the case are already allocated to the natural deviation and capacity. In addition, this should not be done due to the effect of ambient temperature on resistors and capacitor capacitance. For large values of the capacitance of the oxide capacitor C\ and the resistor R\, each time the turn-on delay of the transistor, and hence the HL1 LED, will fluctuate significantly.
HL. Can be replaced by L36B, L56B, L36BSRD, L-297F (head diameter 3mm), L-517hD-F, L-816BRSC-B, L-769BGR, L56DGD, TLBR-5410 and similar.
Due to the use of a field-effect transistor in the circuit, the node practically does not consume current in the time delay mode, and when the LED is activated, the current consumption is almost equal to the current consumption of the blinking LED, i.e., does not exceed 10 mA. This allows you to use almost any DC voltage source as a power source for this node, including the simplest transformerless one with ballast capacitors at the input. The node is not critical to the supply voltage, which makes it almost universal - it is operable at a constant supply voltage in the range of 3 ... 15 V. When the supply voltage increases above 12 V, the limiting resistor R 2 should be multiplied.
Instead of the HL1 LED and a limiting resistor R 2 connected in series (or in parallel) with it, you can turn on a sound piezoelectric capsule, for example KPI-4332-12. It has a built-in 34 with interruption, and when the simulator is activated, the sound will be intermittent and strong enough to be heard in neighboring rooms and outside the front door.
This delay node can be widely used in amateur radio designs.
Flashing LEDs are used in various signal circuits, billboards and signs, electronic toys. The scope of their application is quite wide. A simple LED flasher can also be used to create a car alarm. I must say that the built-in microcircuit (CHIP) makes this semiconductor device blink. The main advantages of ready-made MSDs are: compactness and a variety of colors that allow you to colorfully design electronic devices, for example, an advertising board in order to attract the attention of buyers.
But you can make a blinking LED yourself. Using simple schemes, this is easy to do. How to make a flasher with little skills in working with semiconductor elements is described in this article.
Flashers on transistors
The simplest option is an LED flasher on a single transistor. It can be seen from the diagram that the base of the transistor is hanging in the air. Such a non-standard inclusion allows it to work like a dinistor.
When the threshold value is reached, a breakdown of the structure occurs, the transistor opens and the capacitor discharges to the LED. Such a simple flasher on a transistor can be used in everyday life, for example, in a small Christmas tree garland. For its manufacture, quite affordable and inexpensive radioelements will be needed. A hand-made LED flasher will add a little charm to the fluffy New Year's beauty.
You can assemble a similar device already on two transistors, taking parts from any radio equipment that has served its time. The scheme of the flasher is shown in the figure.
For assembly you will need:
- resistor R = 6.8–15 kOhm - 2 pieces;
- resistor R = 470–680 Ohm - 2 pieces;
- n-p-n-type transistor KT315 B - 2 pieces;
- capacitor C \u003d 47-100 uF - 2 pieces;
- low power LED or LED strip.
Operating voltage range 3-12 volts. Any power supply with these parameters will do. The blinking effect in this circuit is achieved by alternately charging and discharging the capacitors, which entails the opening of transistors, as a result of which current appears and disappears in the LED circuit.
Blinking LEDs can be obtained by connecting the leads to several multi-colored elements. The built-in generator produces pulses for each color in turn. The frequency of the blinking pulse depends on the set program. You can please a child with such cheerful blinking if you install the device in a children's toy, for example, a car.
A good option is to take a three-color flashing LED that has four outputs (one common anode or cathode and three color control outputs).
Another simple option, for the assembly of which you will need CR2032 batteries and a resistor with a resistance of 150 to 240 ohms. A flashing LED will turn out if you connect all the elements in series in one circuit, observing the polarity.
If you manage to assemble funny lights according to the simplest scheme, you can move on to a more complex design.
This LED flasher circuit works as follows: when voltage is applied to R1 and capacitor C1 is charged, the voltage rises on it. After it reaches 12 V, the p-n junction of the transistor breaks down, which increases the conductivity and causes the LED to glow. When the voltage drops, the transistor closes, and the process starts again. All blocks operate at approximately the same frequency, if you do not take into account a small error. A circuit for a five-block LED flasher can be assembled on a breadboard.
Many of us leave our country house unattended for the winter, hoping for strong doors and maybe. And where to go? Electricity is turned off for the winter, and an autonomous security system that can work all winter and even have a decent range, or at least a howler, costs more than the contents of the house. It’s also good if the cottage is located in the coverage area of \u200b\u200bthe mobile operator, but if not? We rake out everything more or less valuable from the house, and lock it up until spring.
However, if strong doors and shutters are equipped with a security system simulator, then the chances of keeping your good can be increased decently. Before getting into the house, any robber studies the strength of doors and windows. In the window, he notices glimpses of the security system (like the one that flashes in the interior of an armed car). His actions? Break? What if it's a burglar alarm and it goes off? Run. And if he does not scream, but turns on a quiet alarm? Maybe a fake? And if not?
In any case, if you install such a dummy, it will not be worse for anyone, especially since its cost is the price of two AA batteries, an LED and an old broken Chinese alarm clock, which costs no more than a dollar new. Work - for two tyks with a soldering iron, without exaggeration. This system is completely autonomous and last season I personally worked around the clock from October to the end of April on one set of batteries for Ukrainian hryvnia apiece. So, if you decide, then you will need:
- 2 finger batteries, and not a super-duper energizer - the current consumption of the device is scanty.
- Indicator LED of any color, but red is worse. Anyone will do, preferably with a lower current consumption, and you can pick it out from anywhere - from an old drive to a receiver, TV or tape recorder - wherever they put them. You can pick out a soft Chinese toy that sparkles in the eyes and croaks "I love you." It will cost with one eye - safety is more expensive.
- I think everyone has a broken disposable Chinese watch. If not, they have a red price in the store - 25 rubles. In principle, any Chinese cheap clock (wall, table) that clicks on the whole house (noiseless with a smooth run will not work) and runs on a single AA battery will do.
We ruthlessly unravel the clock and get to their electronics:
In the figure, the numbers indicate:
- 1, 2 - pins for connecting a stepper motor (looks like a coil).
- 3 - output of the alarm clock
- 4 - power output "-"
- 5 - power output "+"
- 6.7 - conclusions of the sound signal of the alarm clock
We are only interested in three conclusions - 1, 4, 5. We take a soldering iron in our hands and assemble the following circuit, adding one more battery and an LED to the finished one. We remove the tweeter, leaving conclusions 3, 6, 7 free:
There is no power switch - it is not needed. The only thing is that for the second battery you will have to make some kind of cassette - I took it from the second watch. Soldered, plugged in the batteries and you're done. Our LED will start flashing at a frequency of 0.5 Hz. Scary? That's it. And there is no current consumption. The watch mechanism “eats” you know how much, and at the expense of a stepper motor, but we threw it away. It turns out - less self-discharge of batteries. The LED is bigger, but only in moments of short flashes. It remains to push the whole thing into some faceless state-owned box with a hole for the LED, and fix the box itself from the inside of the house so that it can be seen from the window. The power of the output key of the microcircuit is quite enough to power the LED - for the experiment, I had 5 such designs blinking for two weeks. I used LEDs AL307.
P.S. In this (2013-2014) winter, I tried to put an LED from the mouse (optical) manipulator. The current consumption is much less, the brightness is higher. After the New Year went to the country — while flashing. (I turned it on at the beginning of September from two Chinese blue batteries for 70 Ukrainian kopecks. I’ll unsubscribe in the spring.
P.P.S. Batteries worked until the end of May - one leaked, the frequency of flashes decreased by about a third. Replaced. Total - 9 months of continuous work.
Good car alarms like Convoy, Sheriff, Alligator, etc. cost a lot of money. But, having made a simple device (see diagrams), based on a multivibrator, you can easily imitate it and thereby reduce the likelihood of car theft by about 40-50%, or even more. After all, it is easier and safer for car thieves to “open” a car without signs of an alarm, and, unfortunately, there are enough of them.
Usually, on cars with an activated (switched on) alarm, a red, blue or green LED in the cabin flashes. It is usually installed somewhere on the front pillar of the passenger compartment. You can make such a device according to the following scheme.
Details in the simulator are not scarce, transistors can be used KT315, or KT815, KT972, electrolytic capacitors 50-100 uF 16 V, an AL307 LED and several resistors of 10 and 0.5 kOhm. Such radio components can be easily found in old TVs, printers and other devices.
By changing the capacitance of the capacitors, you can change the pause or the glow time of the LED (one is responsible for the pause, the second for the glow). The LEDs in this circuit light up smoothly and also smoothly go out. In my opinion, it is better to leave the glow time and pause symmetrical, i.e. put both capacitors at 100 uF.
The circuit starts working when powered from 3 volts, but it is better to power it from 9-12 V, then the LEDs will glow at maximum and the simulator will be more noticeable.
You can power it from the on-board battery or "Krona" 9 V, in the worst case, 2 batteries for 1.5 V. But! It is necessary to energize secretly, i.e. hide the wiring and the board and bring out only the LED, and not from the cigarette lighter, like some. Otherwise, the thief will immediately understand that this is a fake.
There are other options for blinkers, for example, based on an asymmetric multivibrator. The circuit is built on transistors of different conductivity. Unlike the previous version, this circuit is powered by one or 2 AA batteries, i.e. 1.5 -3 V and lasts for about six months. But, if desired, the device can be powered through a voltage divider and from an on-board 12 V battery.
It works a little differently than the previous circuit, the LED lights up with a flash and quickly goes out. As for me, the first option is more to my liking.
If the device is assembled according to the diagram, without errors, it works immediately and does not require any adjustment, except that you can adjust the blinking frequency if you wish. Transistors in this circuit are silicon, KT315 and KT361 with any letter values. The adjustment (generator frequency) can be changed within fairly large limits using R1 and C1.
But, when assembling, it must be taken into account that the capacitor C1 in this circuit must be of the KM type, that is, not electrolytic, not polar. The LED can be put in any color, but usually it is red or blue.
The circuit itself is economical and continues to work when the voltage drops to 1 volt. Such a simulator, due to its high efficiency, is often still used by radio amateurs and not only to "protect" apartments, country houses, garages, etc. For this purpose, there are more reliable options, such as GSM alarms, in more detail.
There are other schemes of simulators, they all work about the same, but the ones given here are tested and work 100%.
The alarm simulator circuits above are the so-called "passive" protection against theft or theft. Although these schemes are simple, it’s worth it to tinker and make a device, especially if your car is new and attractive, but you don’t want to spend money on a real alarm, or you don’t have the time or desire.
Each of the motorists must have thought about the question - how to make sure that my car is never stolen! Well, the question is right and good, but if there is no way to set an alarm yet, the car is on credit, the salary does not indulge. How to scare off impudent thieves. The answer is simple build and install simple engine fault simulators or alarm simulators yourself.
Anti-theft simulator for VAZ-2109 Contains only three parts: a toggle switch (an ordinary two-position microswitch, the common output of which is soldered to ground); resistor with a resistance of 3 kOhm with a power of 2 W (with a margin); any red LED.
The LED externally does not differ in any way from the LED used in alarms, and starts blinking when voltage is applied (no more than 9 V). When connecting the LED, the polarity must be observed (a plus is the output thickened at the base).
This circuit is designed to be powered by one AA battery, i.e. from 1.5 Volts.
This scheme works as follows. When the power is turned on, the capacitor C2 begins to charge through the resistors R3 and R5 to the value of the supply voltage.
At the end of the capacitor charge, on the basis of the KT3107 transistor there will be a negative potential. During the charge of the capacitor C1, both transistors will open. When the transistor KT3102 is opened, the capacitor C2 will start to discharge and during this time the LED will light up. At the end of the discharge of C2, the LED goes out, both transistors close and the cycle begins again.
The values of the radio components indicated in the diagram set the LED blinking frequency to about 1.5 Hz, which is about 15 flashes in 10 seconds. By changing the capacitance of the capacitor C2, you can change the frequency. The circuit is able to work with a decrease in power up to 1 volt, so you can use batteries that have already worked. On one alkaline AA battery, the alarm simulator circuit can work for about six months. The scheme is borrowed from June 1998.
The circuit is very simple and does not require scarce components. It is easy to assemble even for a beginner radio amateur. You can take any relay that switches to a response voltage of 12 volts.
The switching time of the light emitting components can be adjusted by capacitors C1 and C2 and resistors R2 and R4. Resistor R3 - general regulator "Frequency". The generator itself is made on transistors T1 and T2. On the third, a key circuit is implemented to turn on the relay. On the elements R6 and R7 and C3, C4, a spark-extinguishing chain is made to prevent burning of the relay contacts.
The circuit uses sound signals, and lamps. Only audio or light signals can be used. You can connect it to the foglight circuit through the switch, there are many options, decide for yourself.
Car thieves are becoming extremely resourceful in finding and damaging anti-theft devices. What if the engine starts and stops intermittently? If the car is equipped with equipment that simulates an engine malfunction, a potential thief will most likely not suspect the operation of an anti-theft device and will look for a new victim.
The device provides a normal start of the engine, and after 12 seconds it opens the ignition coil circuit, as a result of which the engine stalls. After 4 seconds, the circuit closes again, allowing the kidnapper to restart the engine. The cycle repeats, and after another 12 seconds the engine stalls and does not start. By this time, the kidnapper may have driven a short distance from the parking lot.
The thief can move off in a car equipped with this circuit, but he will soon give up his intentions after repeatedly stopping the engine. The timer IC periodically cuts off voltage from the ignition coil, simulating an engine failure. The anti-theft device circuit uses 555 timer ICs and low-current C/MOS ICs.
Leaving the car, the driver activates the device with a disguised switch Si. Non-smoking drivers can well disguise the Si switch in a lighter, the wire of which is disconnected from the battery and connected to the circuit at point A. For additional protection, the ignition switch can be connected in series with the Si switch. After the circuit is set to work by switch Si, when the ignition is turned on, trigger 1 is started, assembled on two NAND gates, as a result, 0.5 Hz pulses from the output of the timer 555 go to the shift register CD 4015. It contains two four-bit registers, which in this case are connected in series.
