Ultrasonic mouse repeller

The ultrasonic mouse repeller introduced in this example can generate 18-30kHz sweep frequency ultrasonic waves to drive away mice and various pests. The ultrasonic mouse repeller circuit consists of an astable multivibrator, an emitter follower converter, a voltage controlled oscillator (YC0), a drive amplifier circuit and an ultra-loud piezoelectric ceramic speaker HA, as shown in the figure.

The astable multivibrator is composed of a time base integrated circuit IC1, resistors R1 to R3, capacitor C1, etc.

The emitter follower converter consists of transistor V and its bias components.

The voltage controlled oscillator (VCO) consists of a phase-locked loop integrated circuit IC2 and peripheral resistors and capacitors.

The driving amplifier circuit adopts TWH68 special amplifier module (containing power amplifier circuit and ferrite step-up transformer, etc.).

After the power is turned on, the astable multivibrator oscillates and outputs an 11Hz oscillation signal from pin 7 of IC1. This signal is converted into a sawtooth wave by V and input from pin 9 of IC2. After being controlled and processed by IC2, a sweep frequency signal with a frequency of 18 to 30kHz is output from pin 4 of IC2. After being amplified and boosted by TWH68, this signal drives the super-loud piezoelectric ceramic speaker HA to emit an ultrasonic beam of more than 100dB, which can drive mice and pests within a certain range.

By changing the resistance values ​​of resistors R6 and R7 and the capacitance of capacitor C3, the frequency of the voltage controlled oscillator (VOC) can be changed.

Component Selection

R1~R7 are made of 1/4W carbon film resistors or metal film resistors.

C1 uses polyester capacitor or monolithic capacitor; C2 uses aluminum electrolytic capacitor with a withstand voltage of 10V; C3 and C4 both use high-frequency ceramic capacitors.

VD uses 1N4001 or 1N4007 silicon rectifier diode.

IC1 uses NE555 or μA555 time base integrated circuit; IC2 uses CD4046 phase-locked loop integrated circuit.

HA uses the TWH15 model cylindrical super-loud piezoelectric ceramic speaker.