>   OK, firstly your webpage omits the ground connection to the printer
> port connector.  I think you should have shown that clearly as some
> people will otherwise complain of very peculiar behaviour.


Well, you're right on the whole thing : I made this for simple testings.
The only advantage of this design is the fact that you don't need to
open your computer, nor add a new card. But the biggest problem, as you
mentionned, is the risk for your lpt port.

Anyway, thanks for the comments. May I add them to the web page?

Phil

>
>   You mention obtaining 5V to operate the servos from the PC, and note
> the risk involved.  The risk may be minimised by using a device called
> a "fuse" appropriately.
>
>   The most convenient source for this 5V is the joystick connector where
> this is on a separate sound card - at worst you will torch the sound
> card.
>
>   You can use the keyboard socket with a "piggyback" connector but not
> all motherboards have polyswitches (or fuses) fitted and I for one am
> getting sick of repairing burn holes in motherboards.  (Recall my post
> on the damage caused by the excremental USB adaptor?)

>   Finally, and along the same lines, I do recommend the use of a printer
> adaptor card for experimentation, best one of the old ones using 74LS
> chips as they are actually repairable, modifiable (to bi-directional
> use) and adaptable to non-standard printer addresses.