Using Vex with Dimension Engineering controllers

Don’t drop out

I’m just offering ideas, which is a great way to learn…he mentioned a motor controller and I know others have used that one.

Looks like a nice controller for $32. As far as I can tell it would do the job for you, you would use it in place of the dimension engineering unit. It can use the two analog inputs for limit switches.

Can you tell us a bit more about what you are building?

Don’t laugh…

I looked through the blog a little.
The plastic ball bearings didn’t seem much quieter than the metal ones.
Some mech noise from a robot is part of “the experience”.

What part of R2D2 is the linear slider we are talking about used for?
The projector lens extension, or a claw arm?

I don’t know anything about netbook application programming to USB interfaced devices.
If you are comfortable with programming the USB interface to the pololu thingy,
it seems like a great high-level interface.
Since it takes analog feedback as well, I think you could connect an analog potentiometer to a gear to the rack on the slider. That probably allows you to ask the pololu “where is the rack now?” if you want. It may even allow servo-like feedback control, so you can extend the rack to any nearly-exact position between the limit switches.
Pseudo code for digital limit switches:
cmd: extend forever
action: extend until limit switch
cmd: retract forever
action: retract until limit switch

Pseudo code for analog feedback:
cmd: set to position X1
action: extend or retract to get to position X1, as long as it doesnt hit limit switch
cmd: set to position X2
action: extend or retract to get to position X2, as long as it doesnt hit limit switch

I want to use the linear lift inside the dome to raise the periscope and the life form scanner