Is there a way to make a “ball” (or an object with curved surface) touch sensitive? I want the ball to do something when someone touches it with their hand.

So, currently I got an object out of plastic, i.e. the surface is smooth. The object is hollow. Inside of that object there is an arduino uno with LED and a speaker.

Whenever someone touches it and as long as a person touches, I want the arduino to make a sound or blink with the LED. That object should be also freely moveable, i.e. not tied to something. Its also very light; like a small ball that can fit into your hand.

I want the whole object to be touch sensitive. I want the ball to register whether someone is currently touching the ball or not (I.e. it should also recognize when a person is not touching the ball anymore). Is there a way to accomplish it without buying multiple expensive touch sensors?

At first I was wrapping aluminium foil around the object and put voltage on it so it becomes a capacitor. The downside is that it is not reliable, i.e. sometimes it recognizes the touch sometimes it doesnt. I suspect the aluminium foil area is too big to recognize the touch reliably.

The solution doesn’t have to involve with arduino uno. I could use any arduino as long as it does the job of creating a touch sensitive (curved) surface.

The reason why I want the curved is because I want people to be able to comfortable hold it in their hands. A curved surface is suitable the best for this, I think