Hm...how to better explain. There are a number of applications that use the scroll wheel on a mouse for various things. For instance, in Eagle, the scroll wheel adjusts the zoom level of the current view. What I want to build is a device that lets me adjust that using a knob for instance. The application and computer will think it's just another mouse sending the data. I guess what I'm making is a mouse that has no position sensors, just a scroll. The computer end is handled by Windows and the application. I don't have to change a thing there. I just need to make the device that looks like a mouse to the computer. It won't replace the mouse, just act in concert with it. Is that a bit clearer? Josh -- A common mistake that people make when trying to design something completely foolproof is to underestimate the ingenuity of complete fools. -Douglas Adams On 4/13/05, Jan-Erik Soderholm wrote: > I don't think that your application will ever see the data coming > from the mouse. Windows will catch all mouse data and > act on it as needed. The application currently in "focus" will > then get some Windows message from the kernel to "do" > something just as if you had done something with a real mouse. > > Is that what you want ? > It's not clear if your application expects to get the "raw" > mouse data and act on it as it likes, or if this new device > will replace the standard mouse ? -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist