Making a self-defense device requires careful consideration of safety and legality. Most countries and regions have strict laws regarding the use of self-defense devices. Here are some ways to improve your ability to protect yourself, but be sure to follow local laws and regulations and make sure the measures you take are safe. 1. **Use common objects**: - **Pen**: A hard pen can be used to poke an attacker in sensitive areas, such as the eyes or throat. - **Key**: Thread a key between your fingers to increase the impact of the blow and can also be used to scratch the attacker. 2. **Homemade alarm**: - Use items you carry with you, such as mobile phone apps or small batteries, to make a simple sound device. For example, you can use a small speaker and a switch that makes a sharp sound when pressed to scare off an attacker and attract others' attention. 3. **Use backpacks and packages**: - If you carry a backpack, it can be used as a shield. In an emergency, the edge of the bag can be used to block the attacker's attack. 4. **Learn simple self-defense techniques**: - Find a local self-defense class or video to learn some basic self-defense techniques, such as how to break free from a grasp and how to use sensitive parts of the body. 5. **Use the environment**: - When in danger, you can use the surrounding environment, such as looking for obstacles that can block attackers, or looking for a safe exit. Please be reminded that the most important thing is to try to avoid confrontation in dangerous situations, seek a safe exit or call for help. When facing a direct threat, protecting yourself and ensuring safety is the most important thing.