If the motors are noisy, then it usually means they're drawing too much power, and turning the screw on the drivers should help that - but not if it makes them too weak to hold the weight.

I think the main source of the noise is microstepping - if you've ever used the adafruit shield with microstepping you'll have found the squealing that makes even worse... Not much consolation I know. The speed drop is down to the microstepping, indeed. You will be 4x slower I think, because of the step interpolation. The adafruit shield does actually do an interleaved step style, so with a 200 step motors, you used to tell the machine that it had 400 steps. 200 were "real" steps, and 200 were a kind of half-step.

With microstepping drivers, you tell the machine your true motor steps (200), and a multiplier. To fix the slowness, just increase the speed. I usually run at 2000 steps per sec without any problems. There's a hard limit of around 4000 steps per second, so you might find that it doesn't get any faster past a certain speed near there.

The external power jumper shouldn't make any difference. It is an irritating curiosity that the stepper drivers will not work at all with less than 8v, so 9 is not unusual. As long as your motors are not getting overheated, the voltage can be as high as you want, because you tune the power with the adjustment screw.

That said, if you've got a whining out of them when you do a lock, then there's some vibration, some oscillation, and that's a great way to build up some heat quickly. It's also quite unusual. Do the motors whine if you remove the weight from them entirely?

sn

It isn't luck that made the servo stay on when the motor power times out, it's by design, because you don't want the machine drawing a big stripe through your finished drawing. There's a risk, when you cut the power that the gondola wobbles so much that it draws - even though it's "lifted".

What I normally do is add a deliberate "pen lift" and a "draw to point" to move the pen to a point of natural equilibrium as the very last thing in a queue, so when the motor cuts out, there isn't a big sudden spring back, and the gondola is already at a relaxed position.

Changing almost all of the settings like the timeouts is a matter of recompiling the source and uploading. IT's not hard, you've just got to get the arduino libraries installed. The main polargraph zip bundle has all the libraries in it, they just need dropping into your sketchbook/libraries folder. It's a little idiosyncratic because it should be the particular versions of the libraries in the bundle, and it needs to be Arduino version 1.0.5, rather than the newest one.

sn