Re: [CAD_CAM_EDM_DRO] mouse as a dro?(stupid idea?)

At 01:55 AM 7/12/00 -0000, you wrote:

>Hi ALL!
> I've dowloaded a dro program,and It's reading the mouse position(x
>and y)its' a serial mouse,and with a resolution of 0.0108" according
>to the dro program,Now, if one gets a mouse with a better ressolution
>(if there is one)would be just a matter of taking it apart and
>install it to the machine right?(don't laugh)

I've done some experimenting with a mouse and have mostly given up on
the idea, at least for higher resolutions (eg .001" and higher). What I
found was, as you increase the resolution (via mechanical advantage)
you will likewise be sending much more data from the mouse to the serial
port. Since the baud rate for a mouse is only 1200 baud, you end up with
a time delay between actual stage movement and the computer's ability to
read out the data. It's not to bad at lower speeds but a fast move will
fill the buffer up very quickly. With a servo type system the motor will
run past the desired position and then due to the time lag, correct
the position with a reverse move. This creates a severe 'jittering'
movement as you try to stop the motors at a specific location. This of
course can be corrected by ramping the motor speed and special software
but you'll never be as fast as the electronics in a 'real' DRO system.

For a machine with lower resolution, slow speeds and a fast computer
it could be made to work, however if you can't write your own software
to read multiple mice, you're limited to 2 axis...




Later -

O-Tay (tm)
-----------------------------------------------------------------
Mark A. Taylor (U$UA 15484)
http://www.esper.com/taylorma (Check out the new Garage Sale Area)