Below are simple light and sound circuits, mainly assembled on the basis of multivibrators, for beginner radio amateurs. In all circuits, the simplest element base is used, complex adjustment is not required, and elements can be replaced with similar ones within a wide range.

Electronic duck

A toy duck can be equipped with a simple two-transistor "quack" simulator circuit. The circuit is a classic two-transistor multivibrator with an acoustic capsule in one arm, and two LEDs that can be inserted into the eyes of the toy serve as the load of the other. Both of these loads work alternately - either a sound is heard, or LEDs flash - the eyes of a duck. A reed switch can be used as a power switch SA1 (can be taken from sensors SMK-1, SMK-3, etc. used in systems burglar alarm like door sensors). When a magnet is brought to the reed switch, its contacts are closed and the circuit starts to work. This can happen when the toy is tilted to a hidden magnet or a kind of “magic wand” with a magnet is brought up.

Transistors in the circuit can be any p-n-p type, low or medium power, for example MP39 - MP42 (old type), KT 209, KT502, KT814, with a gain of more than 50. You can also use transistors n-p-n structures, for example KT315, KT 342, KT503, but then you need to change the polarity of the power supply, turn on the LEDs and the polar capacitor C1. As an acoustic emitter BF1, you can use a capsule type TM-2 or a small-sized speaker. Establishing the circuit is reduced to the selection of the resistor R1 to obtain a characteristic quacking sound.

The sound of a bouncing metal ball

The circuit quite accurately imitates such a sound, as the capacitor C1 discharges, the volume of the “beats” decreases, and the pauses between them decrease. At the end, a characteristic metallic rattle will be heard, after which the sound will stop.

Transistors can be replaced with similar ones, as in the previous circuit.
The total duration of the sound depends on the capacitance C1, and C2 determines the duration of the pauses between the “beats”. Sometimes, for a more believable sound, it is useful to choose a transistor VT1, since the operation of the simulator depends on its initial collector current and gain (h21e).

Engine Sound Simulator

They can, for example, sound a radio-controlled or other model of a mobile device.

Transistor and speaker replacement options - as in the previous circuits. Transformer T1 is the output from any small-sized radio receiver (a speaker is also connected through it in the receivers).

There are many schemes for imitating the sounds of birdsong, animal voices, the whistle of a locomotive, etc. The circuit proposed below is assembled on just one digital microcircuit K176LA7 (K561 LA7, 564LA7) and allows you to simulate many different sounds depending on the value of the resistance connected to the input contacts X1.

It should be noted that the microcircuit here works “without power”, that is, no voltage is applied to its positive output (leg 14). Although, in fact, the microcircuit is still powered, but this happens only when the resistance-sensor is connected to the X1 contacts. Each of the eight inputs of the microcircuit is connected to the internal power bus through diodes that protect against static electricity or incorrect connection. Through these internal diodes, the microcircuit is powered due to the presence of positive feedback on power supply through the input resistor-sensor.

The circuit consists of two multivibrators. The first one (on the elements DD1.1, DD1.2) immediately starts generating rectangular pulses with a frequency of 1 ... 3 Hz, and the second one (DD1.3, DD1.4) starts working when the logic level " 1". It generates tone pulses with a frequency of 200 ... 2000 Hz. From the output of the second multivibrator, pulses are fed to a power amplifier (transistor VT1) and a modulated sound is heard from the dynamic head.

If you now connect a variable resistor with a resistance of up to 100 kOhm to the input jacks X1, then there is a feedback on the power supply and this transforms the monotonous intermittent sound. By moving the slider of this resistor and changing the resistance, you can achieve a sound reminiscent of the trill of a nightingale, the chirping of a sparrow, the quacking of a duck, the croaking of a frog, etc.

Details
The transistor can be replaced with KT3107L, KT361G, but in this case, you need to put R4 with a resistance of 3.3 kOhm, otherwise the sound volume will decrease. Capacitors and resistors - of any type with ratings close to those indicated on the diagram. It must be borne in mind that the above-mentioned protective diodes are absent in the K176 series microcircuits of early releases and such instances will not work in this circuit! It is easy to check the presence of internal diodes - just measure the resistance between pin 14 of the microcircuit (“+” power supply) and its input terminals (or at least one of the inputs) with a tester. As with testing diodes, resistance should be low in one direction and high in the other.

The power switch in this circuit can be omitted, since in rest mode the device consumes less than 1 μA current, which is much less than even the self-discharge current of any battery!

Adjustment
A correctly assembled simulator does not require any adjustment. To change the tone of the sound, you can select a capacitor C2 from 300 to 3000 pF and resistors R2, R3 from 50 to 470 kOhm.

flasher

The flashing frequency of the lamp can be adjusted by selecting the elements R1, R2, C1. The lamp can be from a flashlight or a car 12 V. Depending on this, you need to choose the supply voltage of the circuit (from 6 to 12 V) and the power of the switching transistor VT3.

Transistors VT1, VT2 - any low-power corresponding structures (KT312, KT315, KT342, KT 503 (n-p-n) and KT361, KT645, KT502 (p-n-p), and VT3 - medium or high power (KT814, KT816, KT818).

A simple device for listening to the sound of TV programs on headphones. It does not require any power and allows you to move freely within the room.

Coil L1 is a "loop" of 5 ... 6 turns of wire PEV (PEL) -0.3 ... 0.5 mm, laid along the perimeter of the room. It is connected in parallel with the TV speaker through the SA1 switch as shown in the figure. For normal operation of the device, the output power of the TV sound channel must be within 2 ... 4 W, and the loop resistance must be 4 ... 8 Ohms. The wire can be laid under the plinth or in the cable duct, while it must be placed as far as possible no closer than 50 cm from the wires of the 220 V network to reduce AC voltage interference.

Coil L2 is wound on a frame made of thick cardboard or plastic in the form of a ring with a diameter of 15 ... 18 cm, which serves as a headband. It contains 500 ... 800 turns of PEV (PEL) wire 0.1 ... 0.15 mm fixed with glue or electrical tape. A miniature volume control R and an earphone (high-resistance, for example, TON-2) are connected in series to the coil terminals.

Automatic light switch

This one differs from many schemes of similar automata by its extreme simplicity and reliability, and in detailed description does not need. It allows you to turn on the lighting or some electrical appliance for a specified short time, and then automatically turns it off.

To turn on the load, it is enough to briefly press the switch SA1 without fixing. In this case, the capacitor has time to charge and opens the transistor, which controls the switching on of the relay. The turn-on time is determined by the capacitance of the capacitor C and with the nominal value indicated on the diagram (4700 mF) is about 4 minutes. An increase in the on-time is achieved by connecting additional capacitors in parallel with C.

The transistor can be any n-p-n type of medium power or even low power, such as KT315. It depends on the operating current of the relay used, which can also be any other for an actuation voltage of 6-12 V and capable of switching the load of the power you need. You can also use p-n-p type transistors, but you will need to change the polarity of the supply voltage and turn on the capacitor C. Resistor R also affects the response time to a small extent and can be 15 ... 47 kOhm, depending on the type of transistor.

List of radio elements

One of the common hobbies of amateurs and professionals in the field of electronics is the design and manufacture of various homemade products for the home. Electronic homemade products do not require large material and financial costs and can be performed at home, since work with electronics is, for the most part, “clean”. The only exception is the manufacture of various body parts and other mechanical components.

Useful electronic homemade can be used in all areas of life, from the kitchen to the garage, where many are engaged in the improvement and repair of car electronic devices.

DIY in the kitchen

Homemade kitchen electronics can be an addition to existing accessories and accessories. Industrial and home-made electric barbecue grills are very popular among residents of apartments.

Another common example of do-it-yourself home-made kitchen products by a home electrician is timers and automatic switching on of lighting above work surfaces, electric ignition of gas burners.

Important! Changing the design of some household appliances, especially gas appliances, can cause "misunderstanding and rejection" of regulatory organizations. In addition, it requires great care and attention.

Electronics in the car

Home-made devices for a car are most widely used among owners of domestic brands of transport, which differ the minimum amount additional features. The following schemes are in great demand:

• Sound signaling devices of turns and inclusion of a manual brake;
• Operating mode indicator battery and a generator.

More experienced radio amateurs are engaged in equipping their car with parking sensors, electronic power windows, automatic sensors illumination to control the low beam headlights.

Homemade for beginners

Most beginner radio amateurs are engaged in the manufacture of structures that do not require high qualifications. Simple proven designs can serve long time and not only for the sake of benefit, but also as a reminder of the technical "growing up" from a novice radio amateur to a professional.

For inexperienced amateurs, many manufacturers produce ready-made construction kits that contain printed circuit board and a set of elements. Such kits allow you to develop such skills:

• Reading circuit and wiring diagrams;
• Correct soldering;
• Adjustment and adjustment according to the finished method.

Very common among sets. Digital Watch various options performance and degree of difficulty.

As a field of application of knowledge and experience, radio amateurs can design electronic toys using simpler circuits or reworking industrial designs to their wishes and capabilities.

Interesting ideas for crafts can be seen in the examples of making radio-electronic crafts from worn out parts of computer technology.

home workshop

For independent design of radio electronic devices, a certain minimum of tools, fixtures and measuring instruments is required:

• soldering iron;
• Side cutters;
• Tweezers;
• Screwdriver Set;
• pliers;
• Multifunction tester (avometer).

On a note. When planning to do electronics with your own hands, you should not take on immediately complex structures and purchase expensive tools.

Most radio amateurs started their journey with the use of the simplest soldering iron 220V 25-40W, and from the measuring instruments in the home laboratory, the most massive Soviet tester Ts-20 was used. All this is enough for practicing with electricity, acquiring the necessary skills and experience.

It makes no sense for a novice radio amateur to buy an expensive soldering station if there is no necessary experience with a conventional soldering iron. Moreover, the possibility of using the station will not appear soon, but only after the lapse of sometimes quite a long time.

There is also no need for professional measuring equipment. The only serious device that even a novice amateur may need is an oscilloscope. For those already versed in electronics, the oscilloscope is one of the most sought-after measurement tools.

Inexpensive Chinese-made digital instruments can be successfully used as an avometer. With rich functionality, they have high measurement accuracy, ease of use and, importantly, have a built-in module for measuring transistor parameters.

Speaking about the home workshop at homemade, one cannot fail to mention the materials used for soldering. It's solder and flux. The most common solder is the POS-60 alloy, which has a low melting point and provides high soldering reliability. Most of the solders used for soldering various devices are analogues of the mentioned alloy and can be successfully replaced with it.

Ordinary rosin is used as a flux for soldering, but for ease of use it is better to use its solution in ethyl alcohol. Rosin-based fluxes do not require removal from installation after operation, since they are chemically neutral under most operating conditions, and a thin film of rosin formed after evaporation of the solvent (alcohol) exhibits good protective properties.

Important! When soldering electronic components, under no circumstances should active fluxes be used. This is especially true of soldering acid (zinc chloride solution), since even under normal conditions such a flux has a destructive effect on thin copper printed conductors.

For tinning highly oxidized leads, it is better to use an active acid-free flux LTI-120, which does not require rinsing.

It is very convenient to work using solder, which includes flux. The solder is made in the form of a thin tube, inside of which there is rosin.

Good for mounting elements breadboards from double-sided foil fiberglass, which are produced in a wide range.

Security measures

Doing electricity is associated with a risk to health and even life, especially if do-it-yourself electronics are designed with mains power. Homemade electrical devices should not use transformerless power from the household network alternating current. IN last resort, setting similar devices should be produced by connecting them to the network through an isolating transformer with a transformation ratio, equal to one. The voltage at its output will correspond to the mains voltage, but at the same time, reliable galvanic isolation will be provided.

Those who are engaged in radio electronics at home are usually very inquisitive. Amateur radio circuits and homemade products will help you find a new direction in creativity. Perhaps someone will find original solution one problem or another. Some homemade products are already used finished devices connecting them in different ways. For others, you need to completely create the circuit yourself and make the necessary adjustments.

One of the most simple homemade. More suitable for those who are just starting to tinker. If you have an old but working cell phone with a button to turn on the player, you can use it, for example, to make a doorbell to your room. Benefits of this call:

First you need to make sure that the selected phone is capable of producing a sufficiently loud melody, after which it must be completely disassembled. Basically, the parts are fastened with screws or brackets, which are carefully bent. When disassembling, you will need to remember what goes for what, so that later you can reassemble everything.

The player's power button is soldered on the board, and two short wires are soldered instead. These wires are then glued to the board so as not to tear off the solder. The phone is going. It remains to connect the phone to the call button through a two-wire wire.

Homemade for cars

Modern cars are equipped with everything you need. However, there are times when it is simply necessary homemade devices. For example, something broke, given to a friend, and the like. Then the ability to create electronics with your own hands at home will be very useful.

The first thing you can intervene in without fear of damaging the car is the battery. If at the right time charging for the battery was not at hand, you can quickly assemble it yourself. This will require:

The transformer from the tube TV is ideal. Therefore, those who are fond of homemade electronics never throw away electrical appliances in the hope that they will someday be needed. Unfortunately, two types of transformers were used: with one and with two coils. To charge the battery at 6 volts, anyone will go, and for 12 volts, only with two.

The wrapping paper of such a transformer shows the winding leads, the voltage for each winding, and the operating current. To power the filaments of electronic lamps, a voltage of 6.3 V with a large current is used. The transformer can be redone by removing unnecessary secondary windings, or left as is. In this case, the primary and secondary windings are connected in series. Each primary is designed for a voltage of 127 V, therefore, by combining them, they get 220 V. The secondary ones are connected in series to get 12.6 V at the output.

Diodes must be capable of withstanding at least 10 A. Each diode requires a heat sink of at least 25 square centimeters. They are connected to a diode bridge. Any electrical insulating plate is suitable for fastening. A 0.5 A fuse is included in the primary circuit, and 10 A in the secondary circuit. The device does not tolerate a short circuit, therefore, when connecting the battery, the polarity must not be confused.

Simple heaters

In the cold season, it may be necessary to warm up the engine. If the car is parked where it is electricity, this problem can be solved with a heat gun. For its manufacture you will need:

• asbestos pipe;
• nichrome wire;
• fan;
• switch.

The diameter of the asbestos pipe is selected according to the size of the fan to be used. The performance of the heater will depend on its power. Pipe length is everyone's preference. You can assemble a heating element and a fan in it, you can only have a heater. When choosing the latter option, you will have to think about how to let the air flow to the heating element. This can be done, for example, by placing all components in a sealed enclosure.

Nichrome wire is also selected by the fan. The more powerful the latter, the larger diameter you can use nichrome. The wire is twisted into a spiral and placed inside the pipe. Bolts are used for fastening, which are inserted into the drilled holes in the pipe. The length of the spiral and their number are chosen empirically. It is desirable that the coil does not heat up red-hot when the fan is running.

The choice of fan will determine how much voltage you need to apply to the heater. When using a 220 V electric fan, you will not need to use an additional power source.

The entire heater is connected to the network through a cord with a plug, but it must have its own switch. It can be either just a toggle switch or an automatic one. The second option is more preferable, it allows you to protect the overall network. To do this, the tripping current of the machine must be less than the tripping current of the room machine. A switch is also needed to quickly turn off the heater in case of malfunctions, for example, if the fan does not work. Such a heater has its drawbacks:

• harm to the body from asbestos pipes;
• noise from a running fan;
• the smell of dust falling on a heated coil;
• fire hazard.

Some problems can be solved by applying another homemade product. Instead of an asbestos pipe, you can use a coffee can. So that the spiral does not close on the jar, it is attached to a textolite frame, which is fixed with glue. A cooler is used as a fan. To power it, you will need to assemble another electronic device - a small rectifier.

Homemade products bring to the one who deals with them not only satisfaction, but also benefit. With their help, you can save electricity, for example, by turning off electrical appliances that you forgot to turn off. For this purpose, you can use a time relay.

The easiest way to create a timing element is to use the charge or discharge time of a capacitor through a resistor. Such a chain is included in the base of the transistor. The diagram will require the following details:

• high capacity electrolytic capacitor;
• transistor pnp type;
• electromagnetic relay;
• diode;
• variable resistor;
• fixed resistors;
• DC source.

First you need to determine what current will be switched through the relay. If the load is very powerful, you will need a magnetic starter to connect it. The starter coil can be connected via a relay. It is important that the relay contacts can operate freely without sticking. According to the selected relay, a transistor is selected, it is determined with what current and voltage it can work. You can focus on KT973A.

The base of the transistor is connected through a limiting resistor to a capacitor, which, in turn, is connected through a bipolar switch. The free contact of the switch is connected through a resistor to the minus power supply. This is necessary to discharge the capacitor. The resistor acts as a current limiter.

The capacitor itself is connected to the positive bus of the power supply through a variable resistor with a large resistance. By selecting the capacitance of the capacitor and the resistance of the resistor, you can change the delay time interval. The relay coil is shunted by a diode that turns on in the opposite direction. This circuit uses KD 105 B. It closes the circuit when the relay is de-energized, protecting the transistor from breakdown.

The scheme works as follows. In the initial state, the base of the transistor is disconnected from the capacitor, and the transistor is closed. When the switch is turned on, the base is connected to the discharged capacitor, the transistor opens and supplies voltage to the relay. The relay operates, closes its contacts and supplies voltage to the load.

The capacitor begins to charge through a resistor connected to the positive terminal of the power supply. As the capacitor charges, the base voltage begins to rise. At certain value voltage, the transistor closes, de-energizing the relay. The relay disconnects the load. To make the circuit work again, you need to discharge the capacitor, for this the switch is switched.

So. Life has turned out so that I have a house in the village with gas heating. You can't live there permanently. The house is used as a summer cottage. A couple of winters stupidly left the boiler on with minimum temperature coolant.
But there are two downsides.
1. Gas bills are astronomical.
2. If there is a need to come to the house in the middle of winter, the temperature in the house is around 12 degrees.
Therefore, something had to be invented.
I'll clarify right away. The presence of a WI-FI access point in the relay coverage area is mandatory. But, I think, if you get confused, you can put a connected mobile phone next to the sensor and give out a signal from the phone.

Do-it-yourself motion sensor connection 4 pins diagram

Do-it-yourself motion sensor connection diagram

It happens that you need to install lighting in the country, or in the house, which will be triggered when moving or a person or someone else.

The motion sensor, which was ordered by me from Aliexpress, works well with this function. The link to which will be below. By connecting light through the motion sensor, when a person passes through his field of vision, the light turns on, burns for 1 minute. and turns off again.

In this article I tell you how to connect such a sensor if it does not have 3 contacts, but 4 like this one.

Do-it-yourself power supply from an energy-saving light bulb

When to get 12 volts for led strip , or for some other purpose, there is an option to make such a power supply with your own hands.

DIY fan speed controller

This regulator allows smooth adjustment variable resistor fan speed.

Speed ​​controller circuit floor fan came out simple. To fit into the case from an old Nokia phone charger. There also climbed the terminals from a conventional electrical outlet.

The installation is quite tight, but this was due to the size of the case.

DIY lighting for plants

DIY lighting for plants

There is a problem with the lack of lighting. plants, flowers or seedlings, and there is a need for artificial light for them, and this is the light we can provide DIY LEDs.

DIY brightness control

DIY brightness control

It all started with the fact that after I installed halogen lamps at home for lighting. When turned on, they often burned out. Sometimes even 1 bulb a day. Therefore, I decided to make a smooth turn-on of lighting based on a dimmer with my own hands, and I am attaching a dimmer circuit.

Do-it-yourself refrigerator thermostat

Do-it-yourself refrigerator thermostat

It all started with the fact that after returning from work and opening the refrigerator found it warm. Turning the thermostat knob did not help - the cold did not appear. Therefore, I decided not to buy a new unit, which is also rare, but to make an electronic thermostat on the ATtiny85 myself. With the original thermostat, the difference is that the temperature sensor is on the shelf, and not hidden in the wall. In addition, 2 LEDs appeared - they signal that the unit is on or the temperature is above the upper threshold.

DIY soil moisture sensor

DIY soil moisture sensor

This device can be used for automatic watering in greenhouses, flower greenhouses, flower beds and indoor plants. Below is a diagram by which you can make the simplest sensor (detector) of soil moisture (or dryness) with your own hands. When the soil dries out, voltage is applied, with a current of up to 90mA, which is quite enough, turn on the relay.

Also suitable for automatic start drip irrigation to avoid excess moisture.

Fluorescent lamp power circuit

Power supply circuit for a fluorescent lamp.

Often, when energy-saving lamps fail, the power circuit burns out in it, and not the lamp itself. As is known, LDS with burned-out filaments, it is necessary to feed the mains with rectified current using a starterless starting device. In this case, the filaments of the lamp are shunted with a jumper and to which a high voltage is applied to turn on the lamp. There is an instantaneous cold ignition of the lamp, a sharp increase in voltage on it, when starting without preheating the electrodes. In this article, we will look at do-it-yourself LDS lamp start.

USB keyboard for tablet

USB keyboard for tablet

Somehow, suddenly, he took something and decided to buy a new keyboard for his PC. The desire for novelty is unstoppable. Changed the background color from white to black, and the color of the letters from red - black to white. A week later, the desire for novelty naturally went away like water in the sand ( old friend better than the new two) and the new thing was sent to the closet for storage - until better times. And now they came for her, did not even imagine that it would happen so quickly. And therefore the name would be even better suited not which is, but how to connect usb keyboard to tablet

Schemes of homemade measuring instruments

The circuit of the device, developed on the basis of a classic multivibrator, but instead of load resistors, transistors with the opposite main conductivity are included in the collector circuits of the multivibrator.

It's good if your lab has an oscilloscope. Well, if it is not there and it is not possible to buy it for one reason or another, do not worry. In most cases, it can be successfully replaced by a logic probe, which allows you to control the logical levels of signals at the inputs and outputs of digital integrated circuits, determine the presence of pulses in the controlled circuit and reflect the information received in visual (light-color or digital) or audio (tonal signals of various frequencies). ) forms. When setting up and repairing structures based on digital integrated circuits, it is far from always so necessary to know the characteristics of the pulses or the exact values ​​of the voltage levels. Therefore, logic probes make it easy to set up, even if you have an oscilloscope.

A huge selection of different pulse generator circuits is presented. Some of them form a single pulse at the output, the duration of which does not depend on the duration of the triggering (input) pulse. Such generators are used for a wide variety of purposes: simulating the input signals of digital devices, when checking the performance of digital integrated circuits, the need to supply a certain number of pulses to a device with visual control of processes, etc. Others generate sawtooth and rectangular pulses of various frequencies, duty cycles and amplitude

The repair of various components and devices of low-frequency radio-electronic equipment and technology can be greatly simplified if you use a function generator as an assistant, which makes it possible to investigate the amplitude-frequency characteristics of any low-frequency device, transients and nonlinear characteristics of any analog devices, and also has the ability to generate rectangular pulses. form and simplify the process of setting up digital circuits.

When setting up digital devices, one more device is definitely needed - a pulse generator. An industrial generator is a rather expensive device and is rarely on sale, but its analogue, although not so accurate and stable, can be assembled from available radio elements at home

However, the creation of a sound generator that produces a sinusoidal signal is not an easy and rather painstaking task, especially in terms of adjustment. The fact is that any generator contains at least two elements: an amplifier and a frequency-dependent circuit that determines the frequency of oscillations. It is usually connected between the output and input of the amplifier, creating a positive feedback(POS). In the case of an RF generator, everything is simple - a single-transistor amplifier and an oscillatory circuit that determines the frequency are enough. For the audio frequency range, it is difficult to wind the coil, and its quality factor turns out to be low. Therefore, in the audio frequency range, RC elements are used - resistors and capacitors. They filter the fundamental harmonic of the oscillations rather poorly, and therefore the sinusoidal signal turns out to be distorted, for example, limited in peaks. To eliminate distortion, amplitude stabilization circuits are used to maintain a low level of the generated signal when distortion is still invisible. It is the creation of a good stabilizing circuit that does not distort the sinusoidal signal that causes the main difficulties.

Often, having assembled the structure, the radio amateur sees that the device is not working. After all, a person does not have sense organs that allow him to see an electric current, an electromagnetic field, or processes occurring in electronic circuits. Radio measuring instruments help to do this - the eyes and ears of a radio amateur.

Therefore, some means of testing and checking telephones and loudspeakers, audio frequency amplifiers, various sound recording and sound reproducing devices are needed. Such a tool is amateur radio circuits for audio frequency signal generators, or, more simply, a sound generator. Traditionally, it produces a continuous sinusoidal signal, the frequency and amplitude of which can be changed. This allows you to check all ULF stages, find faults, determine the gain, take amplitude-frequency characteristics (AFC) and much more.

A simple amateur radio home-made prefix is ​​considered that turns your multimeter into a universal device for checking zener diodes and dinistors. PCB drawings available