Auto tracking camera/tripod?

Hello,

I would like to have a camera for riding that films itself and also zooms.

So far I have found Pivo, but unfortunately it is not suitable if there are several horses to see.

Then I know Pixio, which would be very good, but unfortunately it's much too expensive.

Is there any other camera that films you and uses a wristband/remote control to keep the focus on you, like Pixio?

Thanks,

Lg