Turning on household electrical appliances on a mobile phone. Do-it-yourself smart GSM socket Do-it-yourself gsm relay

One of the elements of smart home” is a “smart socket”. It is much easier to buy a GSM socket, but it is quite possible to make it yourself. She supports digital standard mobile GSM communications and can be used to turn on and off the alarm in a house or apartment. Because on this moment such devices are widely represented on the market (recently there have been quite a lot of cheap Chinese crafts), then it is not a problem to purchase it at an adequate price. But some prefer the independent production of such outlets.

Short description

"Smart socket" can be used to implement the following functions:

1. Remote control of household appliances: kettle, stove, boiler, etc.
2. In business premises, you can remotely connect computer equipment.
3. GSM-socket allows you to implement the inclusion and deactivation of the automatic irrigation system in personal plots.
4. When connected to such a device, air conditioners and heating devices, it is possible to adjust the microclimate of the room.
5. This socket is well suited for burglar alarm systems.
6. If necessary, you can urgently turn off the power supply in the room.

It is important to note the disadvantages that an SMS socket has. These include:

• the need for a power supply that will smooth out voltage fluctuations in the network (they can disable the GSM switch),
• a sufficiently large power consumption for one device (the communication module "pulls" a lot of electricity),
• the complexity of manufacturing and the high cost of components.

At the same time, a remote-controlled socket can automatically turn on or off from sufficiently large distances using mobile communications(for example, a call or an SMS message).

The GSM socket itself with a temperature sensor looks like an ordinary adapter that plugs into a regular socket. Appliances connected to it turn on after a call or SMS notification, in addition, a smart socket almost always has manual control (as a backup). At the same time, such sockets are designed for loads up to 5 kW, which limits their use. The cost of factory products at the moment reaches 3 thousand rubles (the minimum cost is 900 rubles), while the cost of components for self-manufacturing about 2-2.5 thousand.

A bit of physics: a description of the process

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At the moment, modern telephones use tone dialing. Such signals are called DTMF signals. Their sound depends on the combination of frequencies, and the frequencies are selected in such a way that harmonics are not formed. Therefore, to decode the frequency, it is required to install a decoder (it must be purchased for self-manufacturing of the switch). Accordingly, if, after connecting on the phone, you start pressing the number buttons, then the subscriber who is being called will hear their tones.

On the principle of decoding the tone, a similar socket is created. Keystrokes control turning such devices on and off.

The simplest design

Here is an instruction on how to make a device for decoding a tone that can control a primitive relay. It is the relay that will turn the contacts on and off, and the signals to it will come from the decoder.

Primitive controlled outlet requires, at a minimum, the purchase of a polarized relay.

Now we turn to the description of the scheme. The main device is the mentioned polarized relay. It has 2 coils connected so that when one of them is connected to the network, the armature is attracted to one of the relay cores and does not open the contact even after the power supply is cut off. In order for the contact to move to its original position, an impulse (voltage supply) is needed to the second coil. In this case, the pulse must be of a given amplitude and duration.

To power such a device from the network, it is necessary to solder a diode rectifier. It usually incorporates a 24 V capacitor. Such a circuit seriously violates safety regulations, but its careful use for loads of no more than 3 kW will not lead to serious accidents.

Either an old mobile phone or a special receiver with a decoder should be used as a receiving module. It's easier to buy a primitive mobile phone with a vibrating alert. An optocoupler relay is connected to the vibrating alert; when connecting, check the polarity of the voltage at the vibrating alert outputs; this is important, since the relay has “+” and “-” output contacts. Vibration significantly simplifies the operation of the scheme.

When the vibration mode is triggered, a transistor opens in the optocoupler, which charges the capacitor from the outlet through one of the relay windings, and an open transistor (all this happens in the relay circuit). Then the armature switches and turns on one of the coils of the polarized relay, which closes one of the contacts (to turn on the mains voltage or turn it off).

The polarizing relay is a starter. Further, after the discharge of the capacitor (when the vibration is stopped), the capacitor is discharged, which transfers the armature of the optocoupler relay to its original position. With repeated vibration and repeated operation of the optocoupler relay, the armature of the polarized relay will switch to another coil and the circuit will be disconnected. In this case, there is no need to once again set up a mobile phone, just a call to the number is enough.

The disadvantage of such a scheme will be the activation of the relay when sending SMS spam.

Hello, friends! I want to tell you how you can use an old mobile phone to create something useful. Namely, it will be the simplest GSM alarm system, with which you can remotely control various objects, such as a summer house or an apartment.

What do we need

• any mobile phone with a keypad;
• soldering iron;
• two screws;
• unused bank plastic card;
• clothespin;
• two neodymium magnets in the form of tablets with a diameter of about 10 mm;
• a rectangular plate made of plastic or plywood measuring approximately 50x100 mm.

Getting Started

Conclusion

We now have a lot of cell phones in our hands, each of which can be turned into a GSM alarm system

they either have a completely dead battery, or a broken case, or the buttons do not work well, and they are simply obsolete models, but reliable and completely working.

The idea of ​​using a telephone as part of an alarm system is not new. Back in the days of wired telephones, there were schemes that allowed dialing to a pre-programmed number. With the advent cellular communication and phones that allow dialing without additional circuit solutions, it became possible to create simple and effective enough for use in everyday life and unlicensed projects.

The advantages are clear:

• mobility;
• possibility of use on objects without mains power supply;
• it is easy to change the numbers to which dialing is made;
• it is easy to replace the operator (by changing the SIM card);
• when using the tariff without a subscription. fees and with free dialing to the numbers of your operator, the operation is as cheap as possible.

But do not forget about the nuances of cellular communication:

• cellular communication is not ideally operable (professional work of the operator, communication is not provided at all points in space, and the phone is no no yes and glitches);
• intruders can easily block the operation of the phone by interfering or shielding the protected object.

Nevertheless, GSM and GPRS alarms have better signal coding and are less energy-consuming than radio security systems, and you don’t even need to install an antenna on the site.

Okay, enough preludes, let's move on to "our sheep."

The idea was born a long time ago when I learned to use the button speed dial. At first, everything seemed simple - I assembled the simplest delay circuit, which will be controlled by the security loop sensors and full speed ahead, control the quick dial. I rummaged through the Internet, did not find anything worthwhile, except for the same proposals, the same smart people as me, and began to move the topic.

I assembled a time relay from field effect transistor and a capacitor and stepped on the first rake: such simple circuit poorly controlled by sensors (there is a short response time and contact bounce).

The second rake appeared in the process of working out: any information on the phone screen could completely block the dialer (moreover different brands phones behaved differently). And finally, when the cold came, the third rake appeared: the phone (in the garage) began to fail.

Another rake appeared when searching for keys with which to “press” the phone buttons (galvanic connection of the control circuit with the phone circuit is unacceptable, otherwise the buttons, although they are controlled, completely change their meanings).

And one more rake - to work in the buffer with (which would be both economical and maintain the battery in a state of slight undercharging).

Taking into account the above, the concept of implementation loomed, moreover, any feature phone, including sliders and clamshells. First, the telephone must be controlled by means of a circuit that generates time delays. Secondly, keys with galvanic isolation are needed (special microcircuits such as 564KT3, optocouplers, or banal electromagnetic relays). Thirdly, temperature control of the phone is required. And fourthly, for all this disgrace, you need a reliable and economical power supply.

The time delay forming circuit is needed so that when the sensor is triggered, there is time to dial and listen to the object, which is about 30 seconds.

During these 30 seconds, three more delays occur:

1. the red “Reset” button turns off for half a second to reset any information on the screen;
2. pause for one or two seconds (the phone bugs out without a pause);
3. and finally, a 4-second turn off of the quick dial button.

To implement such an algorithm, I used four waiting multivibrators. There are a lot of options for their implementation, but at my disposal was the well-proven K561LA7 microcircuit. Based on two microcircuits, I implemented four waiting multivibrators. The phone buttons were controlled by a 564KT3 microcircuit (optocouplers are excellent, the switching of phone buttons occurs with a key resistance of up to 200 Ohms, best result with solid state relays (eg AQY 212).

Since the alarm was oriented for, the sensors were used for short circuit. And the circuit was rolled back in the same way with short circuit sensors. Although it is more correct to make an alarm with sensors for opening, then the circuit is more noise-resistant, and security ones, as a rule, open.

The main part of his research was carried out in the conditions of the stand, in winter. I checked how various phones work in frosty conditions and found that all phones do not tolerate cold well. The assembled phone, also in a case and in a pocket, is efficient in good frosts on the street. In my case, all the phones were disassembled, with the battery soldered with wires.

First of all, as a rule, even at zero temperature, the part of the phone circuit responsible for pressing the buttons starts to fail, it may not turn on or dial something else. At low negative temperatures, the radio module fails, the phone seems to work, but it may not see incoming call, or fail to transmit. Cured by packing the carcass of the phone in foam. Even with it taken out, it retained its performance at 27 degrees below zero (we did not fall below).

With the power supply still has not found the best option. I tend to think that the controller should manage it. The fact is that I initially develop a system with a primary source of 12 volts (for example, an old car battery). All converters and stabilizers DC-DC 12 to 5 volts have a certain efficiency, and linear stabilizers completely dissipate power in vain. (This does not apply when you have a 220 volt network at your disposal and losses can be neglected.)

To better understand the problem, we must remember the features of lithium batteries. It would seem, what is easier to take and connect the phone with the battery inserted to charge? It is possible, - the security function will be preserved, at the end of the charge, the phone will write “charge is over” and will wait for the next discharge. But in my developments, I use, to listen to an object when triggered, the answer is by pressing "any" button, carried out by the voltage of the vibrating alert through an optocoupler.

When charging is connected, the vibration mode on most phones is turned off. Yes, and phones often do not have native batteries, but there are batteries from broken ones, and they have to be soldered on wires.

When you try to connect a five-volt power supply to a lithium cell in a buffer, in the hope that the battery protection circuit will turn it off when it reaches the charge, we step on a RAKE. On such a big rake, because after the battery is disconnected by the protection circuit, the phone continues to work from the power supply, and its current is not enough to maintain the operation of the radio module and the phone simply turns off when trying to go on air, goes out. Secondly - lithium batteries, being constantly under 100% charge, begin to slowly but surely die. It is optimal to keep them in a state of 70 percent of a full charge. This is quite easy to achieve, it is necessary that the power supply be adjusted to a voltage of 4.2 - 4.25 volts and at the same time there is no charge current.

In this case, the adjustment should be carried out in several stages, as the battery is charged and the entire load, of course, should be turned off, and the battery at the beginning of the charge should have no more than 50% charge.

As the battery charges, the voltage on the battery increases and the current decreases.

To limit the charge current (and in order to prevent destructive consequences during a short circuit in the electric circuit), I introduced two 28V 2.8W incandescent lamps in parallel into the 12V supply circuit. In this case, the current even short circuit. slightly exceeds 200mA.

Now a few words about which power supply to choose.

When the whole circuit is operating in a steady state, when the battery is charged to nominal, the current consumption from a 12 volt source is about 15mA, even turning on the phone in the dialer mode does not increase the current much and for a short time.

These 15 mA are laid out like this: 5mA is the current consumed by the microcircuit; 5mA - average phone current; and another 5mA is the current consumed by the pulse converter (even in idle mode). By the way, in x.x. the linear stabilizer (for example, on the LM217) consumes practically nothing, but under the maximum current it heats up like a stove.

And now, my patient reader, let me remind you what I said at the beginning, and I said that my first experiments were with a time relay on a field switch and this circuit was the most economical, which I tried to achieve (to give credit, she worked out I have had it for half a year and without a single glitch (although in the conditions of the stand I managed to turn it off).

In the photo, checking the circuit for stand, Samsung phone, later replaced by NOKIA in foam and six months in the garage for sea trials. This set has now been disassembled. Although the idea to assemble a time delay circuit on transistors exists.

But this option is not universal and requires dancing with a tambourine for each phone. And now I can replace the phone with any of my schemes without any problems - complete unification. The 42A / H battery, which the starter did not turn on the car, lasts for almost two months (it is easy to calculate: 15mA * 24 hours * 50 days = 18000ma / h, i.e. 18 A / H such, approximately charge, this battery takes).

Now I am collecting my projects, in the direction of GSM signaling, based on the ATtiny13 pic-controller, this is a small, cheap microcircuit with a supply voltage of 2.7 - 5 volts, which allows it to be powered from the phone's battery. With a minimal body kit, even an external generator is not needed, however, the built-in generator does not allow to reduce clock frequency which would further reduce power consumption. I use AQY212 solid state relays as keys (you can use any, I bought 100 pieces from AliExpress for 900 rubles with delivery). With power supplies did not come to the optimal solution. I put a signalization on the car with a power supply for two ROLLs, one is a current stabilizer, the second is a voltage stabilizer. In the latest designs I use pulse converters. In order not to collect, I for 150 rubles. I buy a USB charger from the cigarette lighter, remove the board from it, remove the connector and unnecessary radio components from the board, solder a 5kΩ multi-turn potentiometer to adjust the output voltage, and solder a 28V 2.8W lamp in front of the converter two pieces in parallel.

I put all this disgrace in a foam box, temperature control is carried out by the power supply. At currents up to 200mA, overheating does not occur.

In one of the first blocks, the charge current of a discharged battery rose to 300 mA, there the heating was good, after that I had to come to grips with the power supplies.

This device is now guarding my and neighbor's garage (two loops with dialing to two numbers).

These were theoretical calculations with practical examples, and now there is little that a radio amateur can repeat, who knows how to hold a soldering iron and distinguishes a resistor from a capacitor, in otherwise reading all of the above makes no sense.

This is a mosfet-based fast call button wiring diagram. The scheme is quite working, collected

and checked.

I take mosfets from the boards of dead computers. They look like in the photo below, a chip with eight legs, of which four are soldered in a bunch, three in a bunch and one separately.

Why they are good: they are controlled by a small potential, respectively, the control circuit is economical, they work very stably and in a wide range of denominations of the applied radio elements, decoupling from the power supply from the phone buttons is provided by a large resistance in the control electrode circuit.

This scheme will work if the number is not redialed when the phone screen is turned off, otherwise it is necessary to block the dialing by powering it from the backlight of the screen. (MOTOROLLA 114 did not require blocking, NOKIA requires blocking. It is carried out by shorting to minus, the point between the 6.2 kΩ resistor and the sensor, powered by the screen backlight with the same mosfet)

In this circuit, it is necessary to use sensors "for short circuit".

There may be a short time spent by the sensor in the triggered state, from this speed dial will not happen and the number will hang on the screen, further speed dialing will be possible after resetting with the “C” button. Nokia dialing is not reset! At the same time, the SMS center must be disabled so that SMS messages do not come to the phone.

Now you understand why I went in the direction of schemes that work according to a given program!

Here is a scheme that works according to a given algorithm:

The circuit is assembled on two K561LA7 microcircuits. Ex. "C" - pressing the "reset" button, ex. "B" - pressing the quick dial button, it must be done through optocouplers, or, like mine, with a 564KT3 microcircuit. You can power the circuit directly from a 12-volt battery, or a 6-15 volt power supply.

The most flexible, in terms of the algorithm of operation, is the circuit assembled on a pic controller. There are a lot of implementation options, depending on what we want to get in the end. The number of radio elements is minimal, which allows you to make a small fee. Power supply from 2.7 volts to 5 volts, respectively, we power it from the phone’s battery (you can even not use a 12-volt battery if the capacity of the lithium cell is enough for continuous operation).

But the implementation of the circuit on the controller may not be possible for all radio amateurs. You need to flash the microcircuit, you need a programmer, you need firmware. At the moment, I have written four firmware, three are uploaded to microcircuits and work.

Here is a variant of one circuit diagrams:

... I put an ellipsis, because I consider the article unfinished, the experiments continue. Recently, the circuits on the controller have occasionally given false alarms, presumably due to the high sensitivity of the loop circuit. It is necessary either to add a key element at the input of the microcircuit, or to correct the firmware.
And I’ll also try, at my leisure, on mosfets to assemble a circuit that works according to a given algorithm. I feel it will be the most economical and noise-immune scheme.

See also:

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In this article, we will tell you how you can turn on household electrical appliances using a mobile phone.

Mobile phones are improving all the time, and not only the design is changing. Phones of old models, having lost demand, gather dust among household items, or in best case sold for a nominal price. But at cell phone weight hidden opportunities! In addition to the fact that your cell phone can be used by law enforcement agencies to spy on you, there are more "pleasant" opportunities for you. It will be about using a mobile phone to perform tasks that are not characteristic of it.

Without major modifications, any mobile phone can be used as a device that phone call turns on or off another device. This device can be any household appliance - a kettle, an iron, a heater, electric lighting lamps, or even an electric heater in the steam room of your country sauna.

Imagine that you are at home in the morning, and you just need to turn on the heater at work, because the public utilities do not heat your office well. Having previously remembered the kind word of the public utilities and calling your “assistant”, you appear at work in a couple of hours, while you are pleasantly pleased with a warm room.

The principle of operation is as follows: Inside any mobile (cellular) phone there is a small micromotor, on the shaft of which an eccentric is fixed. This micromotor is responsible for the “vibration” mode of the phone. During a call, this motor receives constant pressure, it turns a metal eccentric, and since the engine is fixed on the phone, the whole device vibrates. In order for you to understand how this motor looks like, I give a photo of two motors from different phones against the background of a matchbox. It is necessary to turn off this motor, and bring the wires going to it out through an additional connector, or simply directly - with wires. These wires must be connected to the power control circuit shown below.

The scheme is simple, and no additional settings does not require, with proper assembly, it starts working immediately.

The whole circuit is powered through a limiting capacitor C2, a rectifier VD4-VD7, a limiting resistor R7. To smooth out pulsations mains voltage designed electrolytic capacitor C1. To limit the secondary voltage in amplitude and, as a result, to protect against breakdown of the optocoupler D1, the transistor VT1 and the capacitor C1 by a voltage that can exceed the maximum allowable value Uke, a zener diode VD3 is used. It limits the power supply to the circuit at the voltage level of its stabilization.

When a vibrating call appears on the phone, optocoupler D1, transistor VT1 and thyristor VS1 open. An open thyristor turns on relay P1. At the end of the call, the thyristor remains open, therefore the relay P1 remains on. The circuit is returned to its original (disabled) state by pressing the S1 button. The thyristor current is interrupted and it turns off. To control the operation of the device, there is a VD2 LED that indicates that the relay is on.

The diagram shown works on turning on load but a phone call, but if the wire going to the load socket is switched from pin 3 to pin 2 of the contact group of relay P1.2, then the circuit will work on shutdown phone call loads.

To reduce the size, the power supply of the circuit is transformerless. The capacitance of the capacitor C2 is calculated depending on the relay used (its internal resistance). In this case, the executive relay is a 12-volt automotive relay, with internal resistance 80 ohm. If another relay is used, then the value of C2 can be calculated in accordance with the methodology described in the article "Transformerless power supply". Since the circuit is transformerless, for safety reasons, optocoupler D1 is used to galvanically isolate the circuits of the telephone and the executive part of the circuit.

About the details: As an optocoupler D1, you can use any, I have indicated the most common, and sold in almost any radio store - PC120. When connecting the device to the terminals going to the phone's vibrating motor, the polarity must be observed. Transistor VT1 any silicon n-p-n type. Thyristor - also any small-sized, both domestic and foreign in the TO-220 case, for example, the BTA12-400 triac. The zener diode must be installed on a small aluminum radiator with an area of ​​\u200b\u200babout 16 cm 2. Rectifier diodes VD4 - VD7 any silicon for a reverse voltage of at least 400 volts. Capacitor C2 - paper, non-polar, for a voltage of at least 400 volts. For convenience, the device can be mounted in a network extension housing by making a special fastener for a cell phone on it. One of the extension sockets can be used to connect charger phone, and the other - to connect the load. Printed circuit board was not developed, the device was assembled on a mounting panel.

A prerequisite for non-standard use of a mobile phone: when registering a SIM card, turn off all additional services cellular communication, context, receiving and sending SMS-messages, which in a huge number "scam" on our phones without our desire. In addition, it is necessary to turn off the dynamic heads that emit the sounds of the call and the voice of the subscriber. Considering that in your modifications, you are going to use old phone, then with its non-standard use, it is necessary to take care of its operation for a long time. Indeed, on older phones, as a rule, for a reason a large number charge-discharge cycles, the battery is very weak, and it usually makes no sense to buy a new battery. Modifying the phone, it is necessary to provide for its external power supply. This can be done through a standard phone connector, or without a connector, by making small holes in the phone case and applying power directly to the terminals going to the battery. The main thing is not to overdo it with the charge current. Otherwise, the battery may explode.

This scheme can also be used as a device that turns on or off another actuating device by the alarm clock, which is in any (and in this case, in your old) cell phone. Imagine that you are in bed in the morning, and you just need to turn on the electric kettle at exactly six o'clock in the morning without getting out of bed. Instead of you, the above diagram will turn on the electric kettle on an alarm clock. To do this, in addition to the above settings, do the following: turn off the vibration mode for incoming calls and SMS messages, turn on the vibration mode for the alarm clock, set the alarm time.

And the main requirement for an electric kettle is that it should not have touch, but keyboard control, have a shutdown function when water boils, and of course, it must be in good working order.

At present, many devices controlled by software are already being produced industrially. GSM standard(Global System for Mobile Communication), - the digital standard for mobile communications or the now familiar mobile phone. These are various control cabinets for industrial equipment, or even just individual sockets, as shown in Figure 1.

The design looks like a regular adapter that plugs into a wall outlet. The load can be turned on by calling or sending sms via mobile phone. Manual control is also possible using two buttons located on the front panel. The power switched by such sockets, depending on the model, is in the range of 1 - 5 kW, which allows you to turn on almost any load.

Multi-channel sockets are also produced, like a computer “bast shoes”, which allow you to independently control the operation of several loads. Such devices are one of, and therefore, their price is quite high: if you search on the Internet, then prices range from 1000 to 3500 or more rubles.

Picture 1. Remote module sms management

For example, a socket with a remote control via sms (can be controlled by 5 users) with a built-in temperature sensor. With the help of a sensor, the socket can automatically turn off and turn off household appliances in accordance with the ambient temperature:

Figure 2. Socket outlet with remote control sms

Even more expensive than individual sockets are industrial modules. As an example, Figure 2 shows an offer from an online store for the sale of a DTMF control module.

Figure 3

It was from this drawing that the abbreviation DTMF, which is still incomprehensible, appeared on the surface. Let's see what it is below.

DTMF signals

In old phones, dialing was done by rotating the disk: the dialer spring was wound up with a finger for the required number of digits, the disk was spinning back, closing the contact, and clicks were heard in the handset. Such a set was called impulse. Pulse dialing was also used in modern push-button telephones.

Currently, the so-called tone dialing is used. Try to dial a number on a landline phone - sounds of different tonalities are heard in the handset. It listens to DTMF signals, - Dual-Tone Multi-Frequency, - two-tone multi-frequency signal. Figure 4 shows a table that forms the numbers and some characters transmitted when dialing a number.

Figure 4

For example, the number "1" corresponds to a combination of frequencies 697 and 1209 Hz, and the number "9" corresponds to 852 and 1477 Hz. Frequencies are chosen in such a way that when transmitted together, they do not form harmonics. To decrypt tonal bursts, there are specialized microcircuits - decoders, for example IL9270N, HM9270, MT8870. They are just different companies. They may even differ in the number of pins, or, as now in a foreign manner, pins (from the English pin), but they perform the same functions.

In addition to these specialized decoders, DTMF signals can be decoded on digital computers using the Herzel algorithm. Naturally, these signals can also be decoded using microcontrollers or, as they are sometimes called, embedded computers.

Except set phone number DTMF technology is widely used in "smart home" systems, alarm and burglar alarms. DTMF tags are also used in commercial broadcasting.

The DTMF system was developed back in 1961, but reached Russia only in the nineties of the last century. Initially, tone dialing was provided as payable service, and even then not everywhere, since tone dialing is possible only on modern digital telephone exchanges. In general, antediluvian relay stations are still in operation in many places, which allow you to use only pulse dialing.

And now, try to do this experiment: call on a cell phone, well, at least to your work colleague, because you are in the same room all day. After he “picks up the phone”, press any numbers on your phone: DTMF signals in the form of short musical sounds will be heard in the speaker of his phone. (According to the laws of physics, sounds that have a certain frequency are called musical). For example, the noise on the street cannot be considered a musical sound.

The same sounds are also present in the speaker of the telephone headset: the matter is small - just plug the DTMF decoder into the headset jack and here you are, the finished control device. In some cases, the number of managed loads is just one, and it is required to turn it on or off at any time.

Homemade remote devicestelephone control

A few words about the operation of the scheme. The basis of the device is a polarized relay. As can be seen from the diagram, it has two coils connected in such a way that when voltage is applied to one coil, the relay armature is attracted to one core, and remains in this position even if there is no longer voltage on the coil - there is a magnet inside the relay.

In order to snap the armature into the opposite position, it is required to apply voltage, at least a pulse of sufficient duration and amplitude, to another coil. The armature will remain in the attracted state, even when the supply voltage is removed. Isn't it very reminiscent?

The device is powered from the mains, through a half-wave rectifier D1, R1, R2, C1. Capacitor C1 produces a voltage of about 24V. Of course, this is done in violation of all safety rules, but the author assures that if you don’t get too impudent and don’t go where you don’t need to, then ... Well, in general, everything will work out!

The phone must have a vibrating alert: it is to its contacts that the optocoupler relay IC1 will be connected, in the diagram it is the resistor R4 and the output of the optocoupler 1. The polarity of the connection is indicated in the figure. When connected to the phone, the polarity of the voltage on the vibrating alert should be checked using a multimeter or an LED with a resistor.

When the vibration is triggered, the output transistor opens inside the optocoupler (pins 5 and 6). Capacitor C4 is charged from the power supply through the right winding of the relay and the open transistor of the optocoupler. The armature of the relay switches to the left coil, and with contact K1.2 it turns on, and with contact K1.1 it prepares the left coil for the next switching.

Capacitor C4 is discharged through resistor R3 for about five minutes, during which time the status of the device will not be changed from the phone. With all the obvious simplicity, the device has one significant drawback: the ability to get an exotic polarized relay, and even the right passport, is now practically zero. Even the author of the scheme himself writes about this in his description.

Another simple control device is shown in Figure 5.

Figure 5.

Made on a specialized chip - signal decoder DTMFMT8870. Purpose this device in the author's performance remote start and restart your computer. The device works as follows. After you have called this number, dial 1 or 2 after picking up the handset, which corresponds to turning on the computer "POWER" or rebooting "RESET".

The circuit is powered directly from the cell phone, the output transistors of the optocouplers are connected in parallel with the corresponding computer buttons. PC817 optocouplers are widely used in switching power supplies, from computers to mobile phone chargers.

The device is connected to the headset jack, to the speaker outputs, on which, as described above, DTMF signals appear. The main problem with this scheme, when repeated, is that the phone, when a headset is connected, must auto-pick up the handset. But not all phones have this option.

Figure 6.

The circuit is implemented in hardware, i.e. does not contain microcontrollers requiring software, all the logic of work is achieved due to the circuit itself.

The phone call is picked up by the microphone, amplified to right level amplifier, as a result of which the relay is activated, the contacts of which are connected to the "Answer" button (hook up). After this relay trips, a time delay of about 7 seconds starts. If during this time you have time to press the necessary keys, then the DTMF signal will be sent to the DA1 decoder, the output signals of which through the DD3 decoder through the relay can connect - disconnect up to 12 loads.

After 7 seconds, the “Hang up” relay will work (its contacts are connected to the “hang up” button), for subsequent control, one more call will be required. Thus, it turns out that the phone will simply be wrapped with wires: wires from the relay to the buttons, and even the DTMF signal output from the headset jack.

A simpler scheme, meaning by the number of parts, is shown in Figure 7.

Figure 7. Scheme of the load control device by phone (click on the picture to enlarge)

This is where a phone with auto-hookup is used with a headset connected, so you don’t need to solder to the buttons, you just need to connect the headset jack. This scheme provides control of 8 loads, control commands are shown in the diagram description.

But these schemes are not at all those that were called the most complex and serious at the beginning of the article. There are those who use an embedded SIM300D GSM module instead of an old cell phone. Its price is 4200 rubles, although it has already been discontinued. It is in this module that the SIM card is inserted.

Learn more about how to assemble and program the device yourself remote control in the author's development, read here:

Step-by-step instructions on how to independently assemble and configure a load control device on a mobile phone -