u/landomakesstuff

I'm fairly comfortable with basic electronics projects, but I've never done anything with arduino before. I have a project where I need to make or find a proximity sensor of sorts. Here's roughly what I need.

I need to be able to trigger a sound, vibration, or both on object A when it gets close (approximately 0-6 feet) to object B. Both objects will move dynamically in three dimensions, so transmitter(s) and receiver(s) would need to be omnidirectional. The lighter and smaller the better. Power would need to be provided by batteries.

I'm hoping someone can help with a good place for me to start on this project, or if anyone knows of an existing product that does this.