Erratic mouse

Hi Cedrus-gurus,

We’re using ePrime, and we just recently upgraded our response devices from theirs to yours. We’re really happy with the change, but recently something odd started happening: when the Lumina controller is plugged into the laptop, the mouse cursor jumps erratically around the screen, occasionally selecting things as it goes. It’s not that it amplifies your mouse movements, it’s that the mouse just takes off on its own even when the user stops touching the laptop.

It’s a problem that has developed over time, happening with increasing frequency, and it is specific to the Lumina controller – when we plug in (and use) the ePrime response pads, the mouse is fine. When we plug in the Lumina controller, the weirdness begins. It’s also not confined to ePrime – that is, ePrime doesn’t have to be running for the mouse to go haywire. So, it seems to be a Windows thing… (another reason to avoid Windows…).

Have you come across anything like this before?

Thanks in advance!


This is a known issue. From this Lumina support note:

In some instances, it is possible that E-Prime will not “see” the Lumina controller after you turn on your computer. Another symptom might be that the mouse cursor will start moving erratically.

The solution is to unplug the serial cable from the Lumina controller before turning the computer on, and then plug it back after the computer has completed its startup. The reason is this: the Lumina controller works by emulating the PST Serial Response Box Model 200A, which in turn works by sending a constant stream of bytes to the computer all the time. When starting up your computer, Windows tries to be smart and checks all the computer ports (serial, parallel, USB). When it sees this constant stream of data coming, it thinks that the computer has a mouse connected and it reserves it for its own use. Unplugging the serial cable during startup gets around this.