There are 2 ways, the first is mechanical, there are examples over the internet about a device built by Sandy Kidd, but the informations are incomplete, now in the past i have built such kind of devices , and i have identified the missing part. A more modern version is to take some kind of metallic fluid and apply a current orthogonal to a magnetic field , E and B crossing ( Lorentz force , Magnetohydrodynamic effect), the fluid will start to rotate and at the same time will travel in a corkscrew (sp??) fashion, this is the missing point in the Sandy Kidd version, you need two kind of rotations combined , to exploit the graviton ‘spraying’. The second is pure solid state it combines electric field and magnetic field pulsed at 90 degrees phase and crossed, basically you get an electronic version of a mechanical device. For years i have dreamt to build such device, but i am a little bit scared of high voltages , which, to get a visibile effect need to be in the range of several kilovolts, if someone is well versed into high voltage we could start to think about a real device.