Among the many toys with electronics capable of simulating the sounds of animals, is very amusing. For example, a toy cow, imitating mooing, or a pig, saying, "let's Go home, and then I'm hungry already!" I the first mentioned industrial products, decorated in a presentable form miniature soft toys (manufacture of our neighbors from China), e the device emits a sound "Moo-OO-OO" that can be used for various fun devices, adapting a toy, for example, for unusual signal in car.
As a sound signaling device, such a device can be applied practically everywhere in everyday life - from the motion detector of opening the refrigerator door and opener interior (entrance) doors in the apartment until the alarm or phone call lighting - all of the desire and the creative ability of radio Amateurs.
Use unusual sound of the toy can even be in the car, but in as the principal, as in the rules of the road have this through strict regulations. However, as an additional signal - can just don't turn on it passing inspection.
To adapt the device to their goals and objectives, you will need to disassemble it and add a simple (one transistor) circuit power amplifier with connected to the output of a dynamic head power 1 - 5 watts. In photo 2 the external views of electronic components of a Chinese device.
Parallel miniature sound emitter (with dynamic type the coil resistance 250 Ohms, without marking) connected in parallel to a pair of LEDs "eat" a useful power of the already low-power amplifier. As a rule, the indicator light, in addition to sound, in life is not needed, therefore, the conductors connecting both unsolder the LEDs from the circuit Board.
Electrical diagram of an additional amplifier
But the original sound earpiece also not able to generate more power to for example, to sound even room a small area.
Need to increase the power output of the device. In our case, to coordinate output circuit "toys" that have high internal resistance with the low-impedance load (which acts as a dynamic head of BA1 with coil impedance 4 - 16 Ohms), you need to apply a current amplifier on transistor VT1. This transistor can be bipolar (silicon, the structure of n-p-n), and the field. In this case, the resistance of the resistor R1 in the second the case can be higher (up to 1 M) due to the small input currents and a large the input impedance of the FET. Consider an electrical circuit additional amplifier shown in the figure. Indicated on the layout resistance (limiting resistor R1) will allow the device to work without overload. So, as the amplifier power industrial generator sounds "Moo-OO-OO-oooo" applied field-effect transistor and the circuit shown in figure. Since the inclusion of this sound effect will not last for long in time, the VT1 transistor on the heatsink is not installed.
Contact Uвх connect to the Board at the points "regular" dynamic connection the sound of the cap. The + terminal of the cap is connected to the resistor R1, and the total wire - to the General wire of the circuit.
Food Chinese toys made from two series-connected elements such as SC-21, and the working voltage in the sum is 3 V. In practice checked that the electronic "stuffing" toys and extra power can to feed an external stabilized voltage 3 to 8 V. the Upper limit of this the range is final, upon further increasing the voltage generator sounds "Moo-OO-OO" bathed in the micro teardrop may withdraw from system. As a key element in such a power source can use a popular stabilizer CRENA or CREW. If you increase the voltage of the output power also increases.
As transistor VT1 can be applied IRF511, or domestic IRF720 analog - KB.
Is defined in the diagram of the dynamic head of BA1 fit any small-sized with impedance 4-16 Ohms and power up to 5 watts, for example: 0.5 GDS-2, 4ГLW-1, 2GD-36.
The power amplifier is proposed in this paper can be applied in other toys, to hear unusual sound effects. When power is device three times "says" Moo-OO-OO-OO", and then pauses. Following the inclusion of is carried out by closing the contact pads on the "regular" Board toys (see photo 2).
Electronic stuffed toys from China
To adapt the device to a power amplifier in consumer products is required carefully solder the wires to the pad on which end install the switch or the power switch (button) with normally closed contacts. The conductors can be made of flexible copper stranded wires MGTF-0.6 or similar. The length of the wires (to avoid false positives from the crosstalk voltage) should not exceed 0.5 m.
Give an example of application of the device for the sound of the door opening.
For example, a reed switch for opening installed on the door jamb, and the magnet is "implanted" in the door opposite the reed switch. Then when the door is closed the contacts of the reed switch open and the generator "mu-u-u" is silent. When the door is opened, the magnet stops to influence the reed switch whose contacts in the normal state is closed the device srabatyvaet and delivers the sound "Moo-OO-OO" (or another, if you apply another sound toy). Further, even if the door is open for a long time, the generator is silent (it is a peculiarity of toys); new sound will appear at the next the contact closure (or opening a door after it was closed).
Author: A. Kashkarov, St. Petersburg