The most common cause of inaccurate or even zero swing results is lighting. OptiShot is basically a set of infrared emitters and detectors. If there are any other sources of infrared light in the room, then the detectors will have a hard time reading its emitter's infrared pulses. Examples of things that give off too much infrared are the Sun, incandescent light bulbs, halogen light bulbs, and even space heaters. Fluorescent and LED bulbs are the best provided they are not "daylight" or "natural light" or "full spectrum." I should point out that OptiShot will not work in dim light or darkness either.
Next we should look at the club heads themselves. Generally speaking the simple, clean, and reflective design of irons is better at reflecting OptiShot's infrared pulses back into it's detectors than the more complex undersides of some drivers on the market. Matte finish, gun metal, angular bevels, and cutouts do anything but reflect light cleanly down, rather, these surfaces scatter and diffuse the light.
If your lighting is properly set up and you are still having an issue try running OptiShot with the Swing Pad connected and turn off or at least dim all the lights in the room and observe the infrared sensors. With the exception of the Green/Red status light, every second bulb should be steadily glowing faintly red. If some are out that should be lit then the Swing Pad should be replaced. In this case please submit a support request by clicking the link at the top of the page.
To possibly continue using difficult to read drivers try teeing up lower. Another work around others have found is to remove the rubber gripper from the underside of OptiShot and place it on top of the turf just in front of and in the direction of flight, the tee hole in the turf and tee off from there.