Worldwide Campaign to stop the Abuse and Torture of Mind Control/DEWs
Found an instructional to make an emp device. Doesn't seem like it would be too powerful but it's worth a try. The link: https://www.wikihow.com/Make-an-Electromagnetic-Pulse.
Always check your local laws before testing an EMP device. In some parts of the world these are illegal. Be sure you're not breaking the law. The instructions are pretty straight forward. Using a disposable camera, wire and a steel rod is pretty much all you need.