How do you make an ultrasonic mouse repeller? - briefly
Assemble a 20–30 kHz piezoelectric transducer driven by a stable oscillator circuit powered by a 9 V battery, and place it in a plastic housing with a speaker grille to direct the sound outward. Adjust the frequency with a variable capacitor until the emitted ultrasound deters rodents without audible noise.
How do you make an ultrasonic mouse repeller? - in detail
To construct a functional ultrasonic rodent deterrent, follow these exact steps.
Materials
- Piezoelectric ultrasonic transducer (20 kHz–50 kHz, 5 V‑12 V rating)
- Microcontroller board (e.g., Arduino Nano) or dedicated oscillator circuit
- MOSFET driver (IRLZ44N or similar) for power switching
- 12 V DC power supply, regulated to match transducer specifications
- Capacitors (100 µF electrolytic, 0.1 µF ceramic) for smoothing
- Resistors (220 Ω for gate control, 10 kΩ pull‑down)
- Heat‑sink for MOSFET (optional)
- Plastic or metal enclosure with acoustic window (thin silicone membrane)
- Wiring, soldering tools, heat‑shrink tubing
Circuit design
- Connect the microcontroller’s PWM output to the MOSFET gate through the 220 Ω resistor.
- Attach the MOSFET source to ground; the drain connects to the transducer’s negative lead.
- Feed the transducer’s positive lead directly from the regulated 12 V line.
- Place the 100 µF electrolytic capacitor across the power rails to absorb current spikes.
- Add a 0.1 µF ceramic capacitor in parallel with the transducer to stabilize high‑frequency operation.
- Include a 10 kΩ resistor between MOSFET gate and ground to ensure a defined off‑state.
Software configuration
- Set PWM frequency to 30 kHz (within the ultrasonic range).
- Use a 50 % duty cycle to maximize acoustic output while limiting heating.
- Implement a timer to cycle the emitter on for 30 seconds, off for 30 seconds, reducing habituation.
- Provide a manual override switch for continuous operation if required.
Mechanical assembly
- Mount the transducer on the interior side of the enclosure, aligning it with the acoustic window.
- Secure the MOSFET and driver circuit on a small PCB, attaching heat‑sink if the device runs continuously.
- Drill ventilation holes to dissipate heat, ensuring they do not compromise ultrasonic emission.
- Seal all cable entries with silicone to maintain moisture resistance.
Testing and calibration
- Power the unit and measure output frequency with a calibrated ultrasonic meter; adjust PWM if drift occurs.
- Verify voltage across the transducer remains within the rated range under load.
- Place a small animal‑safe test subject (e.g., lab mouse) in a controlled enclosure; observe avoidance behavior when the device is active.
- Record ambient noise levels to confirm no audible sound leaks; adjust enclosure thickness if necessary.
Safety considerations
- Keep the device away from human ears and pets; ultrasonic exposure above 100 kHz can cause discomfort.
- Use insulated wiring and proper grounding to avoid electrical hazards.
- Do not operate the unit in sealed spaces where pressure buildup could damage the transducer.
By adhering to this component list, schematic, firmware, and assembly protocol, a reliable ultrasonic mouse deterrent can be produced for residential or commercial use.