High-loudness alarm generator/electronic sound-imitation mouse repellent/voice recording and playback circuit design

High-volume alarm generator

The circuit of this alarm sound generator is simple, the working performance is stable and reliable, the working voltage is 6V-12V, and it is suitable for use as a siren on cars and motorcycles.

1. Circuit Working Principle

The circuit principle is shown in Figure 27.

This circuit is mainly composed of the sound IC KD-9561 and the switch IC TWH8778. When working, the KD-9561 outputs the alarm signal, which is processed and amplified by the TWH8778 high-current switch IC, and then drives the speaker to emit a loud alarm sound.

2. Selection of components

IC uses KD-9561 sound IC, or KD-9562 sound IC, and connects as required to make it send out warning sound alarm signal. IC2 uses TWH8778 switch circuit. When the power supply voltage is 12V, the speaker BL should be 89, 3W or above speaker or special horn speaker. The resistance value of current limiting resistor R1 is 3000~5109. D2 uses 3V voltage regulator tube. D1 is circuit protection diode, which can be 1N4001.

3. Production and debugging methods

After the circuit is installed, as long as the line is correct, it can be used normally without debugging.

Electronic sound-imitation mouse repellent

Cats are the natural enemies of mice, and using electronic devices to simulate cat sounds to drive away mice is an effective method. Because it is an electronic device, the cat's meow can be loud or soft, fast or slow, and the interval can be long or short. The circuit structure is simple and the cost is low, which is suitable for electronic enthusiasts to make at home.

1. Circuit Working Principle

The circuit working principle is shown in Figure 28.

It consists of a time control circuit, a meowing sound generating circuit, a power amplifier circuit, etc. The time control circuit is composed of a time base circuit IC1 NE555 and its peripheral resistors and capacitors, diodes, etc. It is a pulse oscillator with adjustable duty cycle, and its duty cycle is controlled by R2 and R3. The meowing sound generating circuit is a CMOS integrated circuit IC2 KD-5605, which uses storage technology to solidify the meowing sound inside the circuit. The power amplifier uses the inexpensive and good general low-power audio amplifier integrated circuit IC3 LM386, which is characterized by very few peripheral components, wide voltage range, low distortion, and simple assembly.

When the power switch S is turned on, IC1 is powered on and pulses are continuously outputted at the output terminal ③ of IC1. When there are pulses, the relay J is excited and attracted, and its normally open contact J1 is connected, so that the subsequent circuit obtains power and works, and a cat meowing sound is generated. Every time IC2 is triggered, a cat meowing sound is output, and after being amplified by IC3, it drives the speaker BL to emit a loud and realistic sound.

The sound scares the mice away, thus achieving the purpose of driving them away.

2. Selection of components

IC1 uses 555 time base integrated circuit; IC2 uses KD-5605 sound integrated circuit; IC3 uses LM368. Relay uses JRX-13F small relay, speaker BL should be 89,3W or above or special horn speaker, other components have no special requirements.

3. Production and debugging methods

After the circuit is installed, as long as the line is correct, it can be used normally without debugging.

Voice recording and playback circuit composed of HY560

This circuit is a simple recording circuit. It is small in size, power-saving, and does not require tape.

1. Circuit Working Principle

The circuit principle is shown in Figure 29.

This circuit realizes the circuit function by applying a fully electronic digital recording integrated circuit HY560. The interior of HY560 contains: microphone amplifier circuit, automatic gain control circuit, analog/digital conversion circuit, digital/analog conversion circuit, static memory, logic control circuit, audio amplifier and other units.

When in use, press SB1 (recording button), the sound signal will be received by microphone B1 and converted into an electrical signal, which will be converted into a digital signal and stored in the static memory after passing through the microphone amplification circuit. When the button SB2 (playing button) is pressed, the stored digital recording signal is taken out from the static memory, and after passing through the digital/analog conversion circuit, the digital signal is converted into an analog signal (electrical signal), which will drive the speaker after passing through the audio amplification circuit to produce sound.

2. Component Selection

There are no special requirements for the components of this circuit, and they can be selected according to the parameters given in the circuit diagram.

3. Production and debugging methods

It can be used after assembly without debugging.