Amateur radio circuits and homemade products: how to make a simple device with your own hands, toys for the house and car

Those who are engaged in radio electronics at home are usually very curious. Amateur radio schemes and homemade products will help you find a new direction in creativity. Perhaps someone will find an original solution to this or that problem. Some homemade products use ready-made devices, connecting them in various ways. For others, you need to completely create the circuit yourself and make the necessary adjustments.

Electronic toy

One of the simplest homemade products. More suitable for those who are just starting to tinker. If you have an old but working cellular push-button telephone with a button to turn on the player, you can make, for example, a doorbell to your room from it. The advantages of such a call:

• you can change the melody;
• adjust the ringer volume until it is turned off (and this may be necessary);
• the call will work even if there is no electricity in the network;
• everyone who can use a soldering iron and screwdrivers at least a little can collect such a 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 folded back. When disassembling, you will need to remember what goes for what, so that later you can collect everything.

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

Homemade products for cars

Modern cars are equipped with everything you need. However, there are times when homemade devices are simply needed. 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.

Battery charger

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

• powerful transformer;
• four diodes;
• four radiators for diodes;
• electrical insulating plate;
• power cord.

A transformer from a tube TV is ideal. Therefore, those who are addicted to homemade electronics never throw away electrical appliances, hoping that they will be needed someday. Unfortunately, there are two types of transformers used: with one and with two coils. Anyone will go to charge a 6 volt battery, and only two for 12 volts.

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 high current is used. The transformer can be altered by removing unnecessary secondary windings, or left as it is. In this case, the primary and secondary windings are connected in series. Each primary is designed for a voltage of 127 V, therefore, combining them, they get 220 V. The secondary ones are connected in series to obtain an output of 12.6 V.

Diodes must withstand a current of at least 10 A. Each diode requires a radiator with an area 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 a 10 A fuse in the secondary circuit. The device does not tolerate short circuits, therefore polarity must not be confused when connecting the battery.

Simple heaters

In the cold season, it may be necessary to warm up the engine. If the car is parked where there is an electric current, this problem can be solved by using a heat gun. To make it you will need:

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

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

Nichrome wire is also picked up by the fan. The more powerful the latter, the larger diameter nichrome can be used. The wire is twisted into a spiral and placed inside the pipe. For fastening, bolts are used that are inserted into pre-drilled holes in the pipe. The length of the spiral and their number are chosen empirically. It is desirable that the spiral does not get red-hot when the fan is running.

The choice of fan will determine what voltage needs to be applied 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 via a cord with a plug, but it itself must have its own switch. It can be either just a toggle switch or an automatic machine. The second option is more preferable, it allows you to protect the general network. For this, the tripping current of the machine must be less than the operating current of the room machine. The switch is also needed to quickly turn off the heater in case of malfunctions, for example, if the fan does not work. This heater has its drawbacks:

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

Some problems can be solved by using another homemade product. Instead of an asbestos pipe, you can use a coffee can. To prevent the spiral from closing 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.

Time relay for home

Homemade products bring not only satisfaction, but also benefit to those who are engaged in them. With their help, you can save energy, for example, by turning off electrical appliances that you forgot to turn off. A time relay can be used for this purpose.

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

• high capacity electrolytic capacitor;
• pnp type transistor;
• electromagnetic relay;
• diode;
• variable resistor;
• fixed resistors;
• constant current 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 work freely without sticking. A transistor is selected according to the selected relay, 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 with a minus supply. This is necessary to discharge the capacitor. The resistor acts as a current limiter.

The capacitor itself is connected to the positive rail of the power supply through a variable resistor with high 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, which turns on in the opposite direction. This scheme 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 a certain voltage value, 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 switch the switch.