Keeping cats out of your yard or garden can be a frustrating task. Store-bought cat repellers and deterrents can be expensive and often ineffective. Luckily, with a few basic electronic components from your local hardware store, you can build your own simple but powerful cat repelling device.

In this guide, I will walk you through the full process of constructing a DIY electronic cat repeller using common supplies and basic soldering skills. You will learn:

With just a small investment of time and money, you can humanely and effectively train neighborhood cats to avoid your property.

How Electronic Cat Repellers Work

Before building your device, it helps to understand the science behind why it deters cats.

The repeller uses a sensor to detect when a cat enters the protected area. This sensor triggers a high-voltage pulse generator circuit, which charges a storage capacitor.

When the capacitor reaches sufficient voltage, it discharges through the air, creating a sudden, harmless shock. This triggers the cat's sensitive nervous system and startles it, teaching it to avoid that area in the future.

The pulse is just strong enough to scare, not harm, the cat. The repetition reinforces the lesson that your yard is not a comfortable place for felines.

Purchasing Components

You can find all the electronic components needed at most hardware stores and electronics retailers. The main items you will need are:

Motion Sensor

This acts as the trigger for the entire repeller. A passive infrared (PIR) sensor detects the movement of warm bodies (like cats) across its field of view.

You want one with a wide angle and adjustable sensitivity. You can often salvage these from old security systems or devices.

High Voltage Module

This electronics module produces the rapid high voltage pulses that startle the cat. Look for modules rated for 90V or more output, with adjustable pulse rate and charge time settings.


The capacitor stores the charge from the high voltage module before discharging it through the air. Choose a capacitor with high capacitance, such as 470μF or 1000μF, and voltage rating above 100V.

Battery Pack

A pack of rechargeable AA or AAA batteries will power the device. A pack with at least 2500mAh capacity is recommended for long run times.

Wire, Solder, Housing

Get basic hookup wire, solder, and heat shrink tubing to connect the components. A weatherproof case houses and protects the finished device.

Assembling the Cat Repeller Circuit

With all the components purchased, you can now build the cat repeller circuit:

Step 1: Mount Components

Start by mounting the PIR sensor, high voltage module, and capacitor snugly within the protective case, leaving room for the batteries.

Use hot glue or mounting tape to firmly fix them in place.

Step 2: Solder Sensor Wires

Solder two wires to the PIR sensor output pins - one positive, one ground. This will carry the trigger signal once motion is detected.

Wrap connections in heat shrink or electrical tape.

Step 3: Connect Voltage Module

Solder wires from the positive and ground rails of the high voltage module to the capacitor terminals. One wire goes to positive, the other to negative.

This charges up the capacitor each pulse cycle.

Step 4: Connect Sensor to Module

Next, solder the PIR sensor wires to the voltage module's trigger input pins. This sends the motion signal to initiate pulses.

Use heat shrink tubing to insulate the joints.

Step 5: Install Batteries

Install the battery pack and connect the positive and ground terminals to the matching terminals on the high voltage module.

This powers the entire repeller.

Step 6: Adjust Settings

Finally, tweak the PIR sensitivity and high voltage pulse rate/charge time controls.

Start at maximum sensitivity and rapid pulse rate, then adjust as needed.

Tips for Placement and Use

Follow these tips when siting and activating your DIY cat repeller:

And that's it! Your homemade cat repeller is ready to safely and humanely train roaming cats to avoid your yard or garden. Just flip the switch on to activate it whenever needed.

With a simple homemade circuit, you can take control and rid your property of unwanted feline visitors. Test it, adjust the sensitivity as needed, and enjoy a cat-free space!