In order to obtain a sound signal of high power (10 – 20W) from the simple Assembly of a sound generator, does not require complex amplifiers WOOFER.
The generator on the popular chip KP1006BU1 (DA1) is enabled by almost classical scheme and in the description is not needed. The output frequency is approximately 1000 Hz. It can be considerably corrected by changing the values of the elements C2 and R2. The output frequency in this circuit is calculated by the formula:
F(kHz) = 1,44/(R1 +2xR2)xC2, where the resistance of the resistors R1, R2 in ohms, and the capacitance of the capacitor C1 is in microfarads.
Devices helpers
“RAZLAGALSA” BATTERY
On the recommendation of the manufacturer to eliminate the memory effect of Nickel-cadmium batteries (NiCd) should clear their element to 0.4 V. For the implementation of the above requirements and automate the process of disconnecting the battery reaches level 0.4 V the authors propose a simple device.
To reduce the disconnection threshold of the discharge transistor /T2 is selected with a high rate of current transfer. The load (in addition to the resistor R2) and at the same time an indicator is incandescent НL with a voltage of 1 V at a current of 75 mA. In the absence of a low-voltage light bulbs a consumer may be led АЛ307Б.
MAGNETIC PROBE WITH ALARM
Of the readers who didn’t lose metal parts or tools? Sometimes it happens at the most inopportune time and threatens to permanently stop work. Lost somewhere in the grass screwdriver that fell behind the Cabinet chisel or a failure in a pier of pliers is able to ruffle anyone. In such cases a simple device – a magnetic probe with light and sound alarm. Using this simple device, you can easily find the loss in hard to reach places and the fact findings you will be notified outbreak warning led and buzzer. The principle of operation of the probe is quite simple – on a long rod fixed two magnet “sticking” to the metal object which closes the circuit and lights the warning led. Thus, you can know when the probe with discovery, you can extract the “light”.
REED SECURITY — SIMPLY AND EFFICIENTLY
Security systems are a rapidly developing area of modern electronics. Published a huge number of various schemes and designs that can make anyone a couple of times was holding the soldering iron. For example, “electronic security guards” can warn of an intruder enters the premises or to signal the presence of the recorder for unauthorized sound recordings.
SIGNALLER ICING
The formation of ice on the surface of the blades of the rotor (screw) microgenerator-ROV, wind turbines, anemometers, propeller vanes, fans, degrades performance and may lead to dangerous modes of operation – imbalance, vibration, destruction of bearings, the possibility of destruction of the structural elements is relieved by ice. To prevent such operation it is necessary to detect and eliminate incipient icing.
ECONOMICAL LIGHTING
In large apartments and private homes in the evening and at night it is difficult to follow the dark corridors or staircases to the touch to find the button and turn the lighting.
There’s another alternative — buy a standalone lamps soft light — can be installed in any convenient place at the discretion of the owner.
SENSITIVE METAL DETECTOR
I have designed the metal detector works on the principle of beating is generated due to the difference of the oscillation model and tunable oscillators (5-10-th harmonic, selects the nearest frequency). This allows to increase the sensitivity of the instrument to the point that it becomes possible to detect, say, a five-kopeck coin in the soil at 10 cm, and a steel manhole or pipe — to 65-cm depth. Performed on the available element base, a metal detector does not require careful tuning and maintenance. Power supply — galvanic battery “Crown”.
THE SOUND CONFIRMS THE COMMAND
Simple circuits sound LEDs turn on electronic devices
In Amateur practice, it is frequently necessary to announce the inclusion of any homemade or industrially produced household electronic appliance, equipment or device — which is unusual, pleasant to the ear (if picked up a soft tone audible signal). This is especially true when the appliances operated with a remote control — an acknowledgement signal confirms that the received command. For example, when the operation control of air conditioning — when it is turned on or the mode is changed as a response to user, sound short and melodious sound signal duration of 1 — 2 seconds.
BUZZER
Buzzer on digital circuits switching on/off of electronic devices with power supply of 12 V.
In the car a lot of devices that are included in the operation key or switch. To control the inclusion of a device only by clicking a mechanical switch (which when the machine can not hear) or visual position of a key (which is not easy in motion).
AUTOGRANT IN THE HOUSE
The use of automotive capacitive sensor for home security.
Automotive sensors swing (vibration), RF and capacitor, responsive to the approach of people to the car or movement in the cabin, successfully adapted by hams for specific tasks in the home.
